Category Archives: Telescopes

Using ALMA astronomers have revealed an extremely distant galaxy that looks surprisingly like our Milky Way. The galaxy, SPT0418-47, is gravitationally lensed by a nearby galaxy, appearing in the sky as a near-perfect ring of light. (ALMA (ESO/NAOJ/NRAO), Rizzo et al.)

Distant ‘Milky Way Look-Alike’ Challenges Theories of Galaxy Formation

Using the phenomenon of gravitational lensing astronomers have examined an extremely distant galaxy that shares many features with the Milky Way. The discovery of a calm galaxy so early in the Universe’s history calls into question our theories of how galaxies form. 

Using ALMA astronomers have revealed an extremely distant galaxy that looks surprisingly like our Milky Way. The galaxy, SPT0418-47, is gravitationally lensed by a nearby galaxy, appearing in the sky as a near-perfect ring of light. (ALMA (ESO/NAOJ/NRAO), Rizzo et al.)
Astronomers using ALMA, in which the ESO is a partner, have revealed an extremely distant galaxy that looks surprisingly like our Milky Way. The galaxy, SPT0418-47, is gravitationally lensed by a nearby galaxy, appearing in the sky as a near-perfect ring of light.
(ALMA (ESO/NAOJ/NRAO), Rizzo et al.)

Astronomers have discovered that a distant young galaxy that existed in the very early universe shares some surprising similarities with our galaxy. The fact that the young galaxy named SPT-S J041839–4751.9 or SPT0418–47 for short — located 12 billion light-years from Earth — resembles the Milky Way and the galaxies that surround it presents something of a problem. Galaxies that existed 1.4 billion years after the Big Bang, weren’t supposed to be so calm, unchaotic, and well-formed.

Thus the discovery of this throws many of our theories of galactic evolution into question. In fact, this finding fits into a series of recent discoveries that suggest galaxies began forming much earlier in the Universe’s history than previously believed. 

The research team reconstructed the distant galaxy’s true shape, shown here, and the motion of its gas from the ALMA data using a new computer modelling technique. 
(ALMA (ESO/NAOJ/NRAO), Rizzo et al.)

“This result represents a breakthrough in the field of galaxy formation, showing that the structures that we observe in nearby spiral galaxies and in our Milky Way were already in place 12 billion years ago,” says Francesca Rizzo, a PhD student from the Max Planck Institute for Astrophysics in Germany, and the lead author of a paper detailing the findings published today in the journal Nature

Whilst the observation of this distant galaxy would not have been possible without the impressive technology of the ESO’s Atacama Large Millimeter/submillimeter Array (ALMA) located in the Chilean Andes, it also hinged on the invention of another galaxy, and an extraordinary feature of Einstein’s theory of general relativity. The team reconstructed the accurate image of SPT0418–47 from the ring-like image received by ALMA as a result of gravitational lensing by an intervening galaxy. 

“We have studied in great detail a very distant galaxy. This means going back in time and we see this galaxy when it was very young, 1.4 billion years after the Big Bang,” Rizzo’s co-author, Filippo Fraternali, from the Kapteyn Astronomical Institute, the University of Groningen, Netherlands, tells ZME Science referring to the fact that the light from SPT0418–47 has travelled 12 billion years to reach us.

“Given that galaxies cannot form right after the Big Bang, we can estimate that SPT0418–47 [as we see it] is about 1-billion-years old.”

A Distant Milky Way Doppelganger With Some Key Differences

SPT0418–47 possesses a central bulge and a rotating disc, two features also displayed by the Milky Way and other local galaxies. However, it lacks the Milky Way’s spiral arms and is also much smaller than our home galaxy. This is the first time that astronomers have spotted a central bulge — stars tightly clustered around the galactic centre — in such a distant, and therefore early, galaxy. 

However, Fraternali notes that just because SPT0418–47 resembles the Milky Way at the stage we see it at, that doesn’t mean it evolved just as our galaxy did. “It is important to remark that whilst SPT0418–47 is similar to the Milky Way now, it does not mean that 12 billion years ago the Milky Way looked like SPT0418–47,” the researcher adds.

“In fact, we think that SPT0418–47 will evolve into a galaxy very different from the Milky Way, an elliptical galaxy, much more massive and without gas.”

How Astronomers Reconstructed SPT0418-47 (ALMA (NRAO/ESO/NAOJ)/Martin Kornmesser (ESO)/ Robert Lea)
How Astronomers Reconstructed SPT0418-47 (ALMA (NRAO/ESO/NAOJ)/Martin Kornmesser (ESO)/ Robert Lea)

Another key difference between the two galaxies is that SPT0418–47 is forming stars much more rapidly, unusual for a rotating disk. “SPT-S J041839–4751.9 belongs to a particular population of galaxies that are known as dusty star-forming galaxies,” Simona Vegetti, another co-author on the paper and an expert in gravitational lensing from the Max Planck Institute for Astrophysics, tells ZME Science. “As the name suggests, these are galaxies that are undergoing a significant burst of high-rate star formation.”

Vegetti goes on to explain that astronomers believe that as they age, galaxies like SPT0418-47 will turn into what is referred to as early-type galaxies — a galaxy which has consumed most of its gas and is not forming stars anymore.

“By comparing the properties of SPT-S J041839–4751.9 with those of nearby early-type galaxies, we can learn something about the processes which are responsible for the transformation from one galaxy type to the other,” shes says. “It’s a bit like comparing the properties of young and old people, it gives us some hints on the ageing process.”

But the most puzzling aspect of the distant galaxy is how calm and ordered it appears. Something current cosmological models cannot account for. 

Young and Chaotic? 

Our current cosmological models suggest that the Universe that SPT0418–47 as we see it inhabited was a chaotic and turbulent place. And galaxies found during this epoch are expected to reflect these qualities, even if they do possess some structure, this should be washed out by the violent conditions around them. 

“The general idea was that galaxies at those distances/times were extremely chaotic and one would barely recognise a disc in formation in amongst massive filaments of infalling gas and powerful explosions due to the extremely intense star formation,” says Fraternali. 

Galaxies in the early universe are expected to be the site of powerful phenomena like supernova explosions which release a lot of energy Vegetti explains, adding: “We would expect SPT-S J041839–4751.9 to be very turbulent, or in other words, we expect the motion of gas in this galaxy to move chaotically in winds and outflows.”

But the team’s observations reveal a completely different picture. What they actually found was that the motion of the gas in SPT0418–47 is, in fact, rotating around the centre of the galaxy quietly and in a well-ordered fashion. As Vegetti notes: “It is very hard to explain this behaviour within the context of the latest state-of-the-art numerical simulations of galaxies.”

ALMA (ESO/NAOJ/NRAO), Rizzo et al.

One of the man questions that remain for Fraternali is how common are these features and the relatively ‘calmness’ of SPT0418–47 in other older galaxies? “Because the galaxy has not been selected by us — it was, by chance, perfectly aligned with the lens along the line of sight — we may argue that it could be representative of a large fraction of massive galaxies at that time.”

Thus, staring back in time to conduct further investigation of these distant stars is of vital importance. But, that, as you may imagine, is no easy task. In fact, the study of SPT0418–47, as Fraternali indicates, was only made possible by the intervention of another galaxy coming between it and us, and the ensuing remarkable phenomena of gravitational lensing. 

Galaxies as Lenses — the Power of Gravitational Lensing

The exact alignment of SPT0418–47 and an intervening galaxy means that it appears as a near-perfect ring to the team at ALMA — a structure referred to by astronomers as an ‘Einstein ring’ by astronomers due to its connection to the theory of general relativity — the geometrical theory of gravity put forward by Einstein in the early years of the 20th Century. 

Gravitational lensing hinges on the fact that objects with mass curve the fabric of spacetime around them. The greater the mass, the more extreme the curvature. The most common analogy used to describe this is a stretched rubber-sheet having objects of increasing mass placed on it. A bowling ball creating a greater ‘dent’ on the sheet than a marble or a tennis ball. 

This means that an object like a galaxy with tremendous mass curves the path of light travelling past it, often this results in an object behind the lens appearing to be located in a different place. In extreme cases, creating an ‘Einstein Ring’ built up of light that took different curved paths around the intervening galaxy and thus arrived at Earth at slightly different times. But, isn’t just a beautiful and curious phenomenon of gravity, it’s also a powerful observational tool.  

ight from a distant galaxy is distorted by the gravitational effects of a foreground galaxy, which acts like a lens and makes the distant source appear distorted, but magnified, forming characteristic rings of light, known as Einstein rings. This effect has allowed astronomers to see the distant galaxy SPT0418-47 (which appears as a golden ring in the ALMA images) in finer detail than would have been possible otherwise. The foreground galaxy is not visible in the ALMA images of SPT0418-47 because it is too faint at the wavelengths used. The blue colour used in this schematic to represent this foreground galaxy is artificial. Credit: ALMA (NRAO/ESO/NAOJ)/Luis Calçada (ESO)
Light from a distant galaxy is distorted by the gravitational effects of a foreground galaxy, which acts like a lens and makes the distant source appear distorted, but magnified, forming characteristic rings of light, known as Einstein rings. This effect has allowed astronomers to see the distant galaxy SPT0418-47 (which appears as a golden ring in the ALMA images) in finer detail than would have been possible otherwise. The foreground galaxy is not visible in the ALMA images of SPT0418-47 because it is too faint at the wavelengths used. The blue colour used in this schematic to represent this foreground galaxy is artificial. Credit: ALMA (NRAO/ESO/NAOJ)/Luis Calçada (ESO)

“Because these galaxies are very far, it is challenging to study them in great detail using current telescopes, they are not powerful enough,” Vegetti says. “Our team then uses the effect of strong gravitational lensing to overcome this limitation.”

The process used by the team first involves the search for a pair of galaxies that are far away from each other but appear aligned from our vantage point here on Earth. “The galaxy closer to us will then behave like a lens providing us with a magnified view of the more distant galaxy,” Vegetti elaborates. “It’s like observing through a much more powerful telescope. 

“When we started studying this object we had no idea of what we were going to find. There are almost no other studies of galaxies so young at such a level of detail.”

Vegetti explains that the next generation of telescopes such as the James Webb Space Telescope and the ESO’s Extremely Large Telescope (ELT) should allow for the study of SPT0418–47 galactic contemporaries in much greater detail. This will allow researchers to discover just how common these features are, and in turn, possibly spark a rethink of how early well-ordered galaxies could form in the Universe’s history. She also reserves special praise for this study’s lead author.

“These new facilities will bring this type of analysis to the next level, allowing us to observe even younger galaxies with an even greater level of detail,” Vegetti concludes. “Francesca Rizzo is leading the way in this line of research. She is a brilliant young scientist with whom I enjoy working, so I am looking forward to our next discovery!”


Rizzo. F., Vegetti. S., Powell. D., Fraternali. F., et al, ‘A dynamically cold disk galaxy in the early Universe,’ Nature, [2020].

Do Black Holes Merge? (NASA/Public Domain)

Double Trouble! Hunting for Supermassive Black Hole Mergers

Supermassive black holes sat at the centre of active galaxies could have company. Binary pairs of these titanic cosmic objects could merge to form an even more monstrous black hole. Observational methods are finally becoming sensitive enough to spot such an event. 

The image of a supermassive black hole sat monolithic and alone at the centre of its galaxy, mercilessly swallowing any matter unfortunately enough to cross its path could be seriously challenged over the coming years. Theories of how galaxies grow and evolve and the role supermassive black holes play in these processes have long suggested that these objects may not dwell alone. In fact, not only may such spacetime events live in pairs, but after being brought together, they may merge in what could be the most powerful single event in the Universe, profoundly affecting its evolution.

Do Black Holes Merge? (NASA/Public Domain)
Artist’s impression of a violent merger between two supermassive black holes (NASA/ Pubic Domain)

“Astrophysical black holes are among the most fascinating objects in the Universe: they are ideal laboratories to study the fundamental laws of physics and one of the main drivers of the evolution of the Universe,” explains Alessandra De Rosa, a research astrophysicist at the National Institute of Astrophysics, Roma, Italy. “Understanding how they work and interact with their close environment, and unveil the physical conditions of the medium around them is one of the major challenges of 21st-century Astrophysics.”

Understanding the relationship between black holes and the galaxies that host them is key to building a model that satisfactorily describes the evolution of both. But, thus far evidence of this process is sparse. So, why are supermassive black hole mergers so hard to spot?

Hidden in Plain Sight. How Supermassive Black Hole Binaries and Mergers evade Observation

Despite the potential power of such a merger event, we haven’t as of yet managed to distinguish individual binary supermassive black holes or much evidence that such collisions occur. This is because these pairings and the mergers that may eventually arise from them lurk in what is known as the Active Galactic Nuclei (AGN) — compact regions at the centre of galaxies where the electromagnetic emissions dwarf that of the entire galaxy which surrounds it.

Because this emission — which occurs from the radio wave to the gamma-ray regions of the electromagnetic spectrum — is so powerful, astronomers believe that it does not arise as a result of stellar activity. Rather, they theorise that the powerful electromagnetic radiation emitted by the AGN is the result of at least one supermassive black hole accreting matter — a violent process in which dust, gas, and even stars are ripped apart in a violent and tremendously hot accretion disc surrounding a central supermassive black hole before falling onto what can roughly be described as its ‘surface.’

Here’s the problem; that electromagnetic emission is so overwhelmingly powerful and the AGN is so small in comparion to its host galaxy that there is no way that traditional astronomy — which relies on electromagnetic signals — alone, can distinguish the finer detail of this region. Finer detail that could reveal occupation by two, rather than just one, supermassive black holes.

“Currently, observational evidence for these pairs is almost non-existent,” De Rosa laments. “This can be explained if they quickly shrink to small separations and become impossible to be resolved with telescopes as pairs. So,  we must rely on indirect signatures.”

Fortunately, supermassive black hole mergers, if they occur, would not just be prodigious producers of electromagnetic radiation. They should also produce intense gravitational wave signals.

De Rosa is the lead author of a review paper published in the journal New Astronomy Reviews that looks both the history of our search for supermassive black hole binaries and puts forward a road map for future discovery of such events. The researcher emphasises the importance of ‘multimessenger astronomy’ — which combines traditional electromagnetic observations with the detection of gravitational waves, allowing astronomers to view the Universe in an entirely new way, thus making events and objects are previously hidden to them — events like black hole mergers — accessible.

But before examing mergers, it’s worth considering the truly epic processes that bring supermassive black hole pairings together in the first place.

Cosmic Matchmaking: Bringing Together Supermassive Black Holes

It may not be too surprising to find supermassive black holes hanging-out together in pairs, as our observations of the Universe thus far, show that stellar objects seem to prefer to hang out in pairs. These binary systems are far more common than single star systems such as our solar system, and three-star systems — the latter of which prove to be far too unstable.

“A binary supermassive black hole is made up of two supermassive black holes that are orbiting around each other,” says Julie Comerford, an Associate Professor in the Department of Astrophysical and Planetary Sciences at the University of Colorado, Boulder who specializes in the study of AGNs. “Such binary systems are common in the universe — around half of all stars are in binary systems, where two stars are orbiting around each other.”

As black holes evolve from such stellar objects, and these objects enjoy the company, it would seem intuitive to believe that black hole binaries should be fairly common. There’s a problem with that thinking though.

Only the most massive stars end their lives as black holes, and supermassive black holes are even rarer. Couple that with the fact that most binary systems contain a massive star coupled with a much smaller counterpart. Thus, It’s quite unlikely that two stars in the same binary system would both end up as supermassive black holes. In fact, after the transformation of the first star, it’s likely its partner will be stripped of material and left as a neutron star, a much smaller white dwarf, or destroyed entirely– possibly consumed by its counterpart.

So, if supermassive binaries aren’t likely to grow together, this means that some event must create this union– the merger of two galaxies.

“Each massive galaxy has a supermassive black hole at its centre, so the way you make a supermassive black hole binary is by merging two galaxies together,” Comerford tells ZME Science. “Each galaxy brings its own supermassive black hole to the merger, and as the galaxies combine the supermassive black holes begin their own dance of orbiting around each other.”

This means that spotting such a supermassive black hole binary would provide good evidence that the galaxy it occupies is the result of a merger, or even, that such a merger is still ongoing. It would also give us a hint at what is to come for our own galaxy. “This will one day happen to our Milky Way Galaxy — when it merges with the Andromeda Galaxy in about 4 billion years,” Comerford continues. “Our supermassive black hole and Andromeda’s supermassive black hole will form a binary!”

Mathematical modelling of these galaxy mergers seems to show that the process causes major gas inflow towards the central supermassive black hole — or black holes, as the case may be — this powers accretion and various nuclear processes activating the galactic nucleus. This inflow of gas, dust and other material could also result in the growth of the supermassive black hole.

“Astronomers believe that galaxies merge one or more times during their cosmological life,” says Alessandra De Rosa, who is is a research astrophysicist at the National Institute of Astrophysics, Roma, Italy. “These gigantic collisions are likely to be the primary process by which supermassive black holes are activated.”

Thus, galactic mergers aren’t just responsible for bringing supermassive black holes together, they also could kick start the feeding frenzy that makes an AGN the source of incredibly powerful radiation.

But what happens when these binary pairs of supermassive black holes form? Do they remain in a binary, or do they combine to form an even larger supermassive black hole? The merger of supermassive black holes to form larger objects would explain certainly one lingering cosmological question; how did these objects grow to such tremendous sizes in such a short period of time?

Despite the convenience of this phenomenon to tie up some loose cosmic-ends, we still don’t really know if it’s happening or not.

Using Gravitational Waves to Shed Light on Black Hole Binaries

After being brought together by a galaxy merger, when the supermassive black holes are very small separations, the gravitational waves that they emit carry away energy and enable the black holes to merge.

Thus, supermassive black holes at the centre of each galaxy are dragged close to each other, and eventually, form what is known as a dual active galactic nucleus. Theoretically, the final stage of this coming together — particularly if the black holes are gravitationally bound — will be the coalescence of these monsters in a merger that results in an even larger supermassive black hole. This merger would be accompanied by the emission of a gravitational-wave signal. Signals that thanks to the Laser Interferometer Gravitational-Wave Observatory LIGO, and its upcoming space-based counterpart Laser Interferometer Space Antenna (LISA), we can now theoretically detect.

“We think that binary supermassive black holes ultimately merge with each other and produce very energetic gravitational waves. In fact, supermassive black hole mergers are second only to the Big Bang as the most energetic phenomena in the Universe,” Comerford explains. The problem is, that even LIGO — responsible for the first detection of gravitational waves from colliding stellar-mass black holes — isn’t yet capable of detecting gravitational waves from merging supermassive black hole.

“These gravitational waves are too high frequency to be detected by LIGO, so they have not yet been detected,” Comerford adds. “But, we expect that pulsar timing arrays will detect gravitational waves from supermassive black hole mergers for the first time in just a few years.”

De Rosa concurs with the possible breakthrough in detecting gravitational waves from supermassive black hole mergers, highlighting not just the future contribution of pulsar timing arrays, but also, that of LISA — a space-based laser interferometer set to launch in 2034. “In the next decades, space-borne gravitational wave observatories, such as the next large mission of the European Space Agency, LISA, and experiments such as the Pulsar Timing Arrays, will provide first direct evidence of binary and merging SMBHs in the Universe,” she explains. 

For Comerford, the breakthrough new gravitational wave detection methods and multi-messenger astronomy stand poised to answer fundamental questions that have influenced her entire career. “When I was a graduate student, my group found some intriguing galaxy spectra that we thought might be produced by supermassive black hole pairs. I wondered if these unusual spectra could be the key to finding supermassive black hole binaries. I’ve been working on new and better ways to find supermassive black hole pairs ever since,” the researcher concludes. 

“I think the shocking thing is that we don’t actually know if supermassive black hole binaries merge! It could be that they just circle around each other and are not able to get close enough to each other where the gravitational waves can take over and make them merge. 

“When we detect gravitational waves from supermassive black holes, that will be the first time that we actually know that supermassive black hole binaries do merge.”

Sources and Further Reading 

De Rosa. A, Vignali. C, Bogdanovic. T, et al, ‘The Quest for Dual and Binary Supermassive Black Holes: A Multi-messenger View,” New Astronomy Reviews, [2020]. 

CSIRO’s ASKAP telescope continues to detect new FRBs, adding to the catalogue of these mysterious objects. Credit: ICRAR and CSIRO/Alex Cherney

The Universe’s Missing Matter Problem is Solved

Our theories of the Universe have a missing matter problem: half of its matter is missing. But now this ‘missing baryon problem’ one of the most lingering puzzles in cosmology has been solved.

Analysis of the Cosmic Microwave Background (CMB), the radiation left over from an event that occurred shortly after the ‘Big Bang’ which evenly fills the entire Universe, tells physicists that ‘normal’ or baryonic matter  —  the stuff that forms planets, stars, and our bodies  — should account for roughly 5% of the total matter and energy in the Universe.

The problem has been that until now, roughly half of this baryonic matter (essentially the building blocks of everything we see around us )  has been missing.

Australian astronomers have used fast radio bursts, mysterious blasts of radio-wave radiation that occur in random directions through deep space, whose origins are as of yet unknown, to trace this missing matter for the first time. In the process, the discovery helps confirm that both theories of nucleosynthesis in the early Universe, and our concept of how the cosmos developed immediately following the Big Bang are correct. 

The team’s findings are published in the journal Nature. 

CSIRO’s ASKAP telescope continues to detect new FRBs, adding to the catalogue of these mysterious objects. Credit: ICRAR and CSIRO/Alex Cherney
CSIRO’s ASKAP telescope continues to detect new FRBs, adding to the catalogue of these mysterious objects. Credit: ICRAR and CSIRO/Alex Cherney

“The matter in this study is ‘ordinary’ matter — the material that makes up our bodies, the Earth, and the entirety of the periodic table. We refer to this matter as ‘baryonic’–matter made up of baryons like electron and protons,” says the paper’s co-author Professor J. Xavier Prochaska, UC Santa Cruz, says. The researcher adds that it’s worth noting that this matter isn’t ‘dark matter’ which accounts for roughly 85–90% of the Universe’s matter content.

The two-decade-long hunt for the missing baryonic matter

Thus far astronomers have spent at least two decades searching for this matter using a very precise estimate of the total mass of baryons in our Universe derived from an analysis of data from the early Universe. 

“The hunt for missing matter engaged astronomers across the globe over the past 20 years,” Prochaska explains. “An unofficial accounting estimates 1000+ orbits with the Hubble Space Telescope, thousands of hours with the Chandra X-ray Observatory, and 100+ nights on the largest optical telescopes; these total over $50M USD in operations alone.” 

Yet, despite this monumental effort, a successful census of all the matter in the Universe has not been carried out — until now. Current best measurements account for only around half the baryonic matter, leaving the other half effectively missing.

“When we looked out into the present Universe, we couldn’t find half of the matter that should be there,” says lead author, Associate Professor Jean-Pierre Macquart, Curtin University, International Centre for Radio Astronomy Research (ICRAR). “It was a bit of an embarrassment.”

The issue with finding this missing matter is primarily because it is extremely diffuse and space is extremely sparse. Macquart compares that searching for this matter to searching for just a few atoms in a room the size of the average office. The problem with this matter existing in such a diffuse and tenous gas is that it doesn’t emit light itself, and when background light passes through it, none is absorbed. 

Thus this missing matter doesn’t leave any ‘fingerprint’ and it is, for all practical purposes, invisible. This means that traditional telescopes and the techniques associated with them simply aren’t effective enough to spot such diffuse matter. 

The missing matter that the team of astronomers has located fits within the yellow slice of a pie chart showing the Universe's total energy andmatter content. It isn't dark matter, or dark energy, both of which remain 'missing.'

“The missing matter has a density and temperature that make it effectively invisible to any other technique used to observe it,” explains Prochaska. “Indeed, we have not imaged it either.”

“In a way, you can think of this as ‘grey matter’ in that, it isn’t dark matter,” Macquart explains. “It’s ordinary matter that we could see if it weren’t so diffuse.”

The team of astronomers, therefore, had to find another way to detect that matter. That means finding some other impact or effect that this matter could have, that could be spotted. This is where the phenomenon of Fast Radio Bursts (FRBs) comes in to play.  

Fast Radio Bursts as a detection method

The first Fast Radio Burst was detected in 2007 and since then these, seemingly random blasts of radiation lasting just a few milliseconds, have been recorded many times. This includes the observation in April this year, of the first FRB within our own galaxy, and the first regularly repeating FRB —named FRB 181112 —  in 2018.

Yet, the actual origins of these emissions and their causes are still unknown. 

The FRB leaves its host galaxy as a bright burst of radio waves. (ICRAR)
The FRB leaves its host galaxy as a bright burst of radio waves. (ICRAR)

Despite the mystery around their emission, researchers have still found a way to both localize their source to a host galaxy and to utilize FRBs to measure other phenomena in the Universe. Last year, Prochaska himself was part of research to investigate diffuse gas haloes using FRBs as a probe. The researcher says that from their very discovery by Duncan Lorimer and his student David Narkevic thirteen years ago, he believed that FRBs could be employed in the search for missing baryonic matter. 

“In 2007, I recall discussing Duncan Lorimer’s paper on the first fast radio burst — sometimes referred to as the ‘Lorimer Burst’ — the morning it published,” Prochaska says. “It hit me right then that this would be the best way to find the missing matter.”

To make the detection the team utilized two distinct methods, the dispersion measure and the redshift of the FRB’s origin galaxy. The dispersion measure allows researchers to count the number of encountered electrons as these slow the propagation of the FRB  — with different frequencies that make up the burst be affected to varying degrees.

Whilst, analysis of the spectrum yields the redshift which is effectively a measure of the distance to the FRB’s origin galaxy. This latter part is important because the researchers need to know just how much ‘space’ the FRB has traveled through. 

“Thus, combining redshift and dispersion measure, we can assess the total mass in baryons in the universe,” Prochaska explains. 

It’s all about timing…

FRBs can be used as a probe for baryonic matter because as they travel across the Universe, every atom they encounter slows them down by a tiny amount. This means that they carry with them a trace of every atom they encounter along their line of travel. Even those astronomers can’t see.

The tenous gas cloud that the FRB passes through consists of atoms that have been ionised, this means that the protons and electrons have been separated and float freely in the gas. 

The density of the missing matter is calculated using the distance of the FRB from Earth and the delay between the wavelengths of the FRB, (Credit: ICRAR)
The density of the missing matter is calculated using the distance of the FRB from
Earth and the delay between the wavelengths of the FRB, (Credit: ICRAR)

When radio waves pass through this ionised gas, the different frequencies that make up the FRB propagate at slightly different speeds. This means that the different frequencies which start off perfectly aligned become slightly spread out bt the time the FRB reaches the other side of the gas cloud. 

Macquart describes this phenomenon as exactly what we see when light passes through a prism.

This dispersion in timing is tiny but builds up over the vast distances travelled between galaxies, and the amount of dispersion is exactly proportional to the amount of ionised matter the radio pulse has passed by. 

When travelling through completely empty space, all wavelengths of
the FRB travel at the same speed, but when travelling through the missing matter, some wavelengths are slowed down. (Credit: ICRAR)
When travelling through completely empty space, all wavelengths of
the FRB travel at the same speed, but when travelling through the missing matter, some wavelengths are slowed down. (Credit: ICRAR)

Thus, when the team measure these FRBs they can calculate how smeared out in time the frequencies are, revealing just how much-ionised matter they had passed through on their journey to us. Once the distance of the origin galaxy from which the bursts originated is known, the astronomers could also then measure the average density of the ionised matter, and check this against theoretical predictions.

Leading the way with ASKAP

This combination of methods also required a combination of telescopes and techniques. To conduct their study the team of astronomers turned to CSIRO’s Australian Square Kilometre Array Pathfinder (ASKAP) — a radio telescope consisting of 36 12-inch antennas located roughly 500 miles north of Perth in Western Australia — and some of the world’s most powerful optical telescopes. Prochaska is clear here though: “ASKAP led the way.”

The team used ASKAP to measure the positions of the FRB and thus determine the galaxy from which they originated, unsurprising, as the instrument has become the foremost piece of technology in terms of localising FRBs. 

measures the delay between the wavelengths of the FRB, allowing
astronomers to calculate the density of the missing matter (Credit: ICRAR and CSIRO/Alex Cherney)
CSIRO’s ASKAP measures the delay between the wavelengths of the FRB, allowing
astronomers to calculate the density of the missing matter (Credit: ICRAR and CSIRO/Alex Cherney)

ASKAP found the smeared-out bursts of radio emission, which gave the researchers two key pieces of information — how much ionised matter was between the source of the burst and us on Earth, and where to go looking for the galaxy that the burst had originated in. This is why ASKAP was key to the team, whilst other radio telescopes are able to localise FRBS, almost none of them can pinpoint the location of the burst precisely enough to determine which galaxy they came from.

“To ID an FRB we had to scour through weeks of data to find a single interesting measurement,” Dr Keith Bannister, an Astronomer at CSIRO explains. “Like a needle in a haystack the size of 100 football stadiums.” Fortunately, ASKAP has what Bannister calls a ‘live-action replay’ saving the last 3 billion measurements–just 3 seconds worth of data–from each antenna.

The ASKAP could only solve 2/3 of the missing baryon puzzle, however. Other telescopes were used to measure the redshift of these host galaxies, most incredibly distant and faint, with this measurement giving the team an estimate of the distance and the speed at which the expansion of the Universe is carrying it away. Once the FRB travel distance was known the team could calculate the density of all the atoms along the line of sight.

We know the missing matter is there, now we need to know where ‘there’ is

The idea of ‘finding’ this missing matter may be a touch misleading. The team are quick to point out, that even though they now are able to show that this matter is there, they are yet to determine exactly where it is and how it is distributed.

The next question they will aim to answer is whether this gas is evenly spread smoothly between galaxies, or if it is gathered in haloes and filaments?

Core antennas of CSIRO’s ASKAP radio telescope in Western Australia pointing at the Milky Way. (Credit: CSIRO/ Alex Cherney)
Core antennas of CSIRO’s ASKAP radio telescope in Western Australia pointing at the Milky Way. (Credit: CSIRO/ Alex Cherney)

“Of particular interest to astronomers is to ascertain the fraction of the material that is tightly bound to galaxies versus the fraction that is out in the open Universe — what we refer to as the intergalactic medium or cosmic web,” Prochaska says. But, for him in particular, this finding marks the end of a twenty-year journey. 

“I began this pursuit in 2000 as a postdoc at Carnegie Observatories,” Prochaska concludes. “Ten years after the discovery of Fast Radio Bursts as new radio experiments were tooling up to join the search, I formed a team called ‘Fast and Fortunate for FRB Follow-up’ ) to perform the follow-up with optical telescopes. 

“I never dreamed it would go this smoothly…”

References: Macquart. JP, Prochaska. J. X, McQuinn. M, et al, ‘A census of baryons in the Universe from localized fast radio bursts,’ Nature, [2020].

Focusing on Arrokoth promises to reveal the Kuiper Belt’s secrets

Out beyond the orbit of Neptune and the solar system’s seven other major planets lies a ring of icy bodies known as the Kuiper Belt. The disc that is 20 times as wide and an estimated 200 times as dense as the asteroid belt houses a wide array of objects, including its most famous inhabitant — the dwarf planet Pluto. But, it holds more than objects of ice and rock. The Kuiper Belt may hold the secrets of how the planets of the solar system formed, and the raw materials that created the worlds around us and our own planet. 

“The Kuiper Belt is a repository of the solar system’s most primordial material and the long-sought nursery from which most short-period comets originate,” explains David C. Jewitt, an astronomer based at the University of California, Los Angeles, who is renowned for his study of the solar system and its smaller bodies. “The scientific impact of the Kuiper Belt has been huge, in many ways reshaping our ideas about the formation and evolution of the Solar System.”

Researchers now stand on the verge of unlocking these secrets with the investigation of the Kuiper Belt contact binary Arrokoth (previously known as ‘Ultima Thule’). On January 2019, the object — named for the Native American word for ‘sky’ — became the most distant object ever visited by a man-made spacecraft.

“Most of what we know about the belt was determined using ground-based telescopes. As a result, Kuiper Belt studies have been limited to objects larger than about 100 km because the smaller ones are too faint to easily detect,” says Jewitt. “Now, 5 years after its flyby of the 2000-km-diameter Kuiper Belt object Pluto, NASA’s New Horizons spacecraft has provided the first close-up look at a small, cold classical Kuiper Belt object.”

The data collected by the New Horizons probe has allowed three separate teams of researchers to conduct the most in-depth investigation of a Kuiper Belt object ever undertaken. In the process, they discovered that our current knowledge of how these objects form is very likely incorrect. From all the evidence the three teams collected, it seems as Kuiper Belts form as a result of a far more delicate, low-velocity process than previously believed. As most astrophysicists believe that these objects — planetesimals — acted as the seeds from which the planets grew, this new model changes our idea of how the solar system formed.

How Kuiper Belt Bodies Get in shape

The majority of the clues as to Arrokoth’s low-velocity formation originate from its unusual binary lobed shape. The larger lobe is joined to the smaller lobe by an extremely narrow ‘neck.’ What is especially interesting about this shape — reminiscent of a bowling pin or a snowman — is that the lobes are perfectly aligned. 

Scientists have used all available New Horizons images of Arrokoth, taken from many angles, to determine its 3D shape, as shown in this animation. The shape provides additional insight into Arrokoth’s origins. The flattened shapes of each of Arrokoth’s lobes, as well as the remarkably close alignment of their poles and equators, point to an orderly, gentle merger of two objects formed from the same collapsing cloud of particles. Arrokoth has the physical features of a body that came together slowly, with ‘locally-sourced’ materials from a small part of the solar nebula. An object like Arrokoth wouldn’t have formed, or look the way it does, in a more chaotic accretion environment. (NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute/Roman Tkachenko)

John Spencer, Institute Scientist in the Department of Space Studies, Southwest Research Institute in Boulder, Colorado, led a team of researchers that reconstructed Arrokoth’s 3-dimensional shape from a series of high resolution black and white images. Spencer’s paper concludes that Arrokoth’s lobes are much flatter than was previously believed but despite this, both lobes are denser than expected.

William McKinnon, Professor of Earth and Planetary Sciences at the Califonia Institute of Technology, and his team ran simulations of different formation methods to see which conditions led to the shape recreated and Spencer and his colleagues.

Velocity simulations of the formation of Arrokoth show that the unique shape of the bi-lobed comtact binary could only be acheived by a low-velocity gathering of small particles. (W.B McKinnon, et al)
Velocity simulations of the formation of Arrokoth show that the unique shape of the bi-lobed contact binary could only be achieved by a low-velocity gathering of small particles. (W.B McKinnon, et al)

McKinnon and his team discovered that the shape of Arrokoth could only be achieved as a result of a low-velocity formation–around 3 m/s. This presents a problem to current theories of how planetesimals form.

The suggested method of planetesimal formation suggests high-velocity particles smashing together in a process called hierarchical accretion. The simulations that McKinnon produced suggest that such high-velocity collisions would not have created a larger body, but rather, would have blown it apart. The geometrical alignment of the larger and smaller lobes indicates to the team that they were once co-orbiting bodies which gradually lost angular momentum and spiralled together, resulting in a merger.

“Arrokoth’s delicate structure is difficult to reconcile with alternative models in which Arrokoth Kuiper Belt objects are fragments of larger objects shattered by energetic collisions,” Jewitt says. This supports a method of planetesimal formation called ‘cloud collapse.’

Jewitt, Science, (2020)

“A variety of evidence from Arrokoth points to gravitational collapse as the formation mechanism.  The evidence from the shape is probably most compelling,” William Grundy of Lowell Observatory says. “Gravitational collapse is a rapid but gentle process, that only draws material from a small region. Not the much more time consuming and violent process of hierarchical accretion – merging dust grains to make bigger ones, and so on up through pebbles, cobbles, boulders, incrementally larger and larger,
with more and more violent collisions as the things crashing into each other.”

Grundy, whose team analysed the thermal emissions from Arrokoth’s ‘winter’ side, goes on to explain that the speed at which cloud collapse occurs and the fact that all the material that feeds it is local to it means that all the Kuiper planetesimals should be fairly uniform.

Cold Classicals: Untouched and unpolluted

Arrokoth is part of a Kuiper Belt population referred to as ‘cold classicals,’ this particular family of bodies is important to astrophysicists researching the origins of the solar systems. This is because, at their distance from the Sun within the Kuiper Belt, they have remained virtually untouched by both other objects and by the violent radiation of the Sun.

As many of these objects, Arrokoth in particular, date back 4 billion years to the very origin of the solar system, they hold an uncontaminated record of the materials from which the solar system emerged and of the processes at play in its birth.

Arrokoth's relative smoothness can be seen from comparisons to comets found in other areas of the solar system (J. R. Spencer et al., Science10.1126/science.aay3999 (2020).
Arrokoth’s relative smoothness can be seen from comparisons to comets found in other areas of the solar system (J. R. Spencer et al., Science10.1126/science.aay3999 (2020).

Arrokoth has a relatively smooth surface in comparison with other comets, moons and planets within the solar system. It does show the signs of a few impacts, with one very noticeable 7km wide impact crater located of the smaller lobe. This few craters dotted across Arrokoth’s surface do seem to point to a few small high-velocity impacts. The characteristics of Arrokoth’s cratering allowed the team in infer its age of around 4 billion years. This places its birth right around the time the planets had begun to form in the solar system.

“The smooth, relatively un-cratered surface shows that Arrokoth is relatively pristine, so evidence of its formation hasn’t been destroyed by subsequent collisions,” Spencer explains. “The number of craters nevertheless indicates that the surface is very old, likely dating back to the time of accretion.

“The almost perfect alignment of the two lobes, and the lack of obvious damage where they meet, indicate gentle coalescence of two objects that formed in orbit around each other, something most easily accomplished by local cloud collapse.”


As mentioned above, Will Grundy and his team were tasked with the analysis of thermal emissions in the radio band emitted by the side of Arrokoth facing away from the Sun.

W. M. Grundy et al., Science
10.1126/science.aay3705 (2020).

“We looked at the thermal emission at radio wavelengths from
Arrokoth’s winter night side.  Arrokoth is very cold, but it does still emit thermal radiation,” Grundy says. “The signal we saw was brighter, corresponding to a warmer temperature than expected for the winter surface temperature.  Our hypothesis is that we are seeing emission from below the surface, at depths where the warmth from last summer still lingers.”

Grundy’s team also looked at the colour imaging of Arrokoth with the aim of determining what it is composed of. “We looked at the variation of colour across the surface, finding it to be quite subtle,” he says. “There are variations in overall brightness, but the colour doesn’t change much from place to place, leading us to suspect that the brightness variations are more about regional differences in surface texture than compositional differences.”

The team determined that Arrokoth’s dark red colouration is likely to be a result of the presence of ‘messy’ molecular jumbles of organic materials that occur when radiation drives the construction of increasingly complex molecules–known as tholins.

“One open question is where Arrokoth’s tholins came from,” Grundy says. “Were they already present in the molecular cloud from which the Solar System formed?  Did they form in the protoplanetary nebula before Arrokoth accreted? Or did they form after Arrokoth accreted, through radiation from the Sun itself?”

The researcher says that all three are possible, but he considers the uniformity of Arrokoth’s colouration to favour the first two possibilities over the third. The team also searched Arrokoth for more recognisable organic molecules, spotting methanol–albeit frozen solid–but, not finding any trace of water. Something which came as a surprise to Grundy. “It was surprising not to see a clear signature of water ice since that’s such a common material in the outer solar system. Typically, comets have
around 1% methanol, relative to their water ice.”

The team believe that this disparity arises from the fact that Arrokoth accreted in a very distinct chemical environment at the extreme edge of the nebula which collapsed to create the solar system.

“If it was cold enough there for carbon monoxide (CO) and methane (CH4) to freeze as ice onto dust grains, that would enable chemical mechanisms that create methanol and potentially destroy water, too. But those mechanisms could only work where these gases are frozen solid,” Grundy says.  “Arrokoth appears to be sampling a region of the nebula where such conditions held. 

“We have not seen comets so rich in methanol, which probably means we have not seen comets that formed in this outermost part of the nebula.  Most of them probably originally formed closer to the Sun (or else at a different time in nebular history when the chemical conditions were somewhat different).”

Looking to future Kuiper Belt investigations

Investigating Kuiper Belt objects is no walk in the park, with difficulties arising from both the disc’s distance from the Sun and from the fact that Kuiper Belt objects tend to be very small. Grundy explains that as sunlight falls off by the square of its distance, object s as far away as the Kuiper Belt require the most powerful telescopes to do much of anything.

“Sending a spacecraft for a close-up look is great to do, but it took New Horizons 13 years to reach Arrokoth,” Grundy says. “It’ll probably be some time yet before another such object gets visited up-close by a spacecraft.”

Investigations of the Kuiper Belt aren't easy, the next flyby might be decades away ( Kuiper Belt Illustration –
Investigations of the Kuiper Belt aren’t easy, the next flyby might be decades away ( Kuiper Belt Illustration –

“For flybys, the journey times are very long–we flew for 13 years to get there–navigation is difficult because we don’t know the orbits of objects out there very well, we’d only been tracking Arrokoth for 4 years,” Spencer explains. “The round-trip light time is long, which makes controlling the spacecraft more challenging, and light levels are very low, so taking well-exposed, unblurred, images is difficult.”

Spencer adds that from Earth, objects like Arrokoth are mostly very faint, meaning only a small fraction of them have been discovered and learning about their detailed properties is difficult even with large telescopes. These difficulties mean that one of the things left to discover is just how common bi-lobed contact binaries like Arrokoth are in the Kuiper Belt. “Some evidence from lightcurves suggests up to 25% of cold classical could be contact binaries,” he says. ” We know that many of them are binaries composed of two objects orbiting each other, however.”

Fortunately, telescope technology promises to make leaps and bounds over the coming decades, with the launch of the space-based James Webb Space Telescope (JWST) in 2021 and the completion of the Atacama Desert based Extremely Large Telescope (ELT) in 2026.

“Both will help,” says Grundy.  “Larger telescopes are needed to collect more light and feed it to more sensitive instruments.  JWST and the new generation of extremely large telescopes set to come online over the coming years will enable new investigations of these objects.”

In terms of future spacecraft visits, Grundy believes that researchers and engineers should be thinking small, literally: “If technical advances were to enable highly miniaturized spacecraft to be flown to the Kuiper belt more quickly, that could enable a lot of things.  The big obstacles to doing that with today’sCubeSats are power, longevity, and communications, but the rapid advance of technology makes me hopeful that it will be possible to do a whole lot more with tiny little spacecraft within a few decades. 

“It’s funny how progress calls for ever bigger telescopes and ever smaller

 Future advances in telescope technology promised more detailed examinations of Kuiper Belt objects like Arrokoth. (NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute/National Optical Astronomy Observatory)
Future advances in telescope technology promised more detailed examinations of Kuiper Belt objects like Arrokoth. (NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute/National Optical Astronomy Observatory)

Of course one of the most lasting changes that result from this landmark triad of studies on Arrokoth published in Science is the move away from hierarchical formation models and the adoption of a gravitational or cloud collapse model to explain the creation of planetesimals. This shift will resolve one of the long-standing issues with the hierarchical model, the fact that they work quite well to grow things from dust size to pebble size, but once pebble size is reached, the particles quickly spiral-in toward the Sun. 

“I think it will shift the focus to the circumstances that trigger the collapse.  It’s a very fast way of making a planetesimal–decades instead of hundreds of millennia–but the circumstances have to be right for instabilities to concentrate solids enough for them to collapse,” Grundy explains. “It will be interesting to map out where and when planetesimals should form, what their size distributions should be, and where the solids that they are formed from should have originated.”

Original research:

W. M. Grundy et al., Science
10.1126/science.aay3705 (2020).

W. B. McKinnon et al.,
Science 10.1126/science.aay6620

J. R. Spencer et al., Science
10.1126/science.aay3999 (2020).

D. C. Jewitt et al., Science
10.1126/science.aba6889 (2020).

Astronomers capture the most detailed image of the sun

In what could be a key step to solve several long-standing mysteries around it, a group of astronomers have released the highest resolution image of the sun, obtained thanks to observations by the Inouye solar telescope in Hawaii.

This is the highest resolution image of a star yet. Credit: NSO/NSF/AURA.

The images show a never-before-seen level of structure hidden within the plasma exterior. This was achieved thanks to the telescope’s 30km resolution, which is more than twice that of the next best solar observatories around the world. The telescope is located at a 3,000 meters volcano on the island of Maui.

“These are the highest resolution images of the solar surface ever taken,” said Thomas Rimmele, the director of the Inouye solar telescope project. “What we previously thought looked like a bright point – one structure – is now breaking down into many smaller structures.”

A close-up of the solar telescope’s first image of the sun. Credit: NSO/NSF/AURA.

The solar telescope revealed the sun’s surface to be speckled with granular structures, each the size of France. At the center of each grain, there are rising columns of plasma, heated to almost 6,000ºC (10,800F). When the plasma cools, it goes back below the surface through channels between the granular structures.

The surface of the sun in motion. Credit: NSO/NSF/AURA.

Valentin Pillet, the director of the National Solar Observatory, described the challenges that involved taking the solar images. Keeping the telescope’s mirror at ambient temperature while looking at the sun proved difficult, as temperature deviation causes air turbulences that can alter the images.

A closeup of the features captured by the Inouye solar telescope, showing the vast scale of the sun. Credit: NSO/NSF/AURA.

At the same time, Pillet said that in order to carry out the project they emptied a swimming pool worth of ice into eight tanks every day. Then, during the day, coolant was routed through the ice tanks and distributed through the pipes of the observatory. They also positioned 100 air jets behind the main mirror.

The experts at the observatory also deflected the incoming sunlight from the primary mirror into a chamber of mirrors, located below the dome. The light was then bounced from mirror to mirror. The observatory is equipped with a full set of instruments, which will allow measuring the magnetic field from the surface of the sun later in the year.

Such observations will help to solve long-standing mysteries around the sun, such as why its atmosphere is heated to millions of degrees when the surface is 6,000ºC. Understanding the physics behind the solar flares will be able to improve the ability to predict space weather.

“On Earth, we can predict if it is going to rain pretty much anywhere in the world very accurately, and space weather just isn’t there yet,” said Matt Mountain, president of the Association of Universities for Research in Astronomy. “What we need is to grasp the underlying physics behind space weather, and this starts at the Sun, which is what the Inouye Solar Telescope will study over the next decades.”

Astrophysicists find more evidence of ‘wandering’ black holes

Artist’s conception of a dwarf galaxy, its shape distorted, most likely by a past interaction with another galaxy, and a massive black hole in its outskirts (pullout). The black hole is drawing in material that forms a rotating accretion disc and generates jets of material propelled outward. Image credit: Sophia Dagnello, NRAO/AUI/NSF

Dwarf galaxies have traditionally been considered too small to host massive black holes, but new research emerging from Montanna State University (MSU) has revealed dozens of examples. The research, published in the Astrophysical Journal has delivered another surprise, these black holes aren’t located where scientists usually expect to find them.

“All of the black holes I had found before were in the centres of galaxies,” says Amy Reines, an assistant professor in the Department of Physics in the College of Letters and Science. “These were roaming around the outskirts. I was blown away when I saw this.”

Reines and her team searched 111 dwarf galaxies within a radius of a billion-light-years of Earth using the National Science Foundation’s Karl G. Jansky Very Large Array at the National Radio Astronomy Observatory, Albuquerque, New Mexico. During the course of their search, they identified 13 galaxies that very probably host black holes, the majority of which were not centralised. 

Reines is also a researcher in the MSU’s eXtreme Gravity Institute, which unites astronomers and physicists in order to study phenomena in which the gravitational influence is so powerful that it blurs the separation of space and time. This includes events and objects such as neutron stars, black holes, mergers and collisions between the two and even, the initial extreme period of rapid expansion of the universe — the big bang. 

The researcher explains that whilst stellar-mass black holes — those with a mass of up to 10 times that of our Sun — form as large stars undergo gravitational collapse, we are, thus far, uncertain how supermassive black holes form. This class of black hole which can have masses of up to billions of times that of the Sun is most commonly found in the centre of galaxies. 

This is certainly the case with our galaxy, the Milky Way, which hosts the supermassive black hole Sagittarius A* (SgrA*) at its centre. Dwarf galaxies are smaller than spiral galaxies like the Milky Way, containing a few billion stars rather than 100–400 billion as spiral galaxies tend to.

The results collected by Reines confirm computer simulations generated by Jillian Bellovary, assistant professor at Queensborough Community College, New York and Research Associate at the American Museum of Natural History. 

How black holes get lost

Bellovary’s computer simulations suggested that black holes could be disturbed from the centre of dwarf galaxies by interactions they undergo as they travel through space. This result coupled with Reines’ study have the potential to change the way we look for black holes in dwarf galaxies going forward. This change in thinking could also impact theories of how both dwarf galaxies and supermassive black holes form. 

“We need to expand searches to target the whole galaxy, not just the nuclei where we previously expected black holes to be,” Reines adds.

No stranger for the search for black holes, Reines has been hunting these events for a decade, ever since she was a graduate student at the University of Virginia. Whilst she initially focused on star formation in dwarf galaxies, her research led her to something else that captured her interest: a massive black hole “in a little dwarf galaxy where it wasn’t supposed to be.”

Henize 2–10: a dwarf galaxy that hides a massive secret ( Reines et al. (2011))
Henize 2–10: a dwarf galaxy that hides a massive secret ( Reines et al. (2011))

The little dwarf galaxy she refers to is Heinze 2–10, located 30-million-light-years from Earth, which had previously been believed too small to host a massive black hole. “Conventional wisdom told us that all massive galaxies with a spheroidal component have a massive black hole and little dwarf galaxies didn’t,” Reines explains, adding that when she discovered such a relationship it was a “eureka” moment. After publishing these findings in the journal Nature she continued searching for further black holes in dwarf galaxies. “Once I started looking for these things on purpose, I started finding a whole bunch,” Reines says.

Visible-light images of galaxies that VLA observations showed to have massive black holes. Center illustration is artist’s conception of the rotating disk of material falling into such a black hole, and the jets of material propelled outward. Image credit: Sophia Dagnello, NRAO/AUI/NSF; DECaLS survey; CTIO
Visible-light images of galaxies that VLA observations showed to have massive black holes. Center illustration is artist’s conception of the rotating disk of material falling into such a black hole, and the jets of material propelled outward. Image credit: Sophia Dagnello, NRAO/AUI/NSF; DECaLS survey; CTIO

Changing her tactics by shifting from visual data from radio signals, Reines uncovered over 100 possible black holes in her first search of a sample that included 40,000 dwarf galaxies. In current search, as described in the latest paper, Reines returned to radio searches, hunting for radio signatures with that sample. This, she says, should allow her to find massive black holes in star-forming dwarf galaxies, even though she has only found one thus far. 

“When new discoveries break our current understanding of the way things work, we find even more questions than we had before,” comments Yves Idzerda, head of the Department of Physics at MSU.

As for Reines, the search continues. 

“There are lots of opportunities to make new discoveries because studying black holes in dwarf galaxies is a new field,” she said. “People are definitely captivated by black holes. They’re mysterious and fascinating objects.”

Original research:

The rocket carrying CHEOPS splits depositing its cargo into a low-Earth orbit. (ESA)

New European exoplanet-hunting telescope launches into space

After an initial setback yesterday (17/12/19) due to a software error, the European Space Agency’s (ESA) CHaracterising ExOPlanets Satellite — or CHEOPS — telescope has finally launched from the European Spaceport in Kourou, French Guiana.

Blast off: CHEOPS begins its journey to space (NASA)

CHEOPS was aboard a Russian Soyuz-Fregat rocket which blasted off at 9:54 am European time. The Rocket will take approximately 145 minutes to place the CHEOPS unit into a rare pole to pole low-Earth orbit. 

The telescope hitched a ride with an Italian radar satellite, the rocket’s primary payload. 

CHEOPS being loaded aboard its method of transport (ESA)

CHEOPS is the result of a collaboration between 11 member countries within the ESA, with Switzerland taking the lead on the project. Two of the country’s leading Universities — the University of Geneva and the University Bern — worked together to equip CHEOPS with a state of the art photometer.

This powerful device will measure changes in the light emitted by nearby stars as planets pass by — or transit — them. This examination reveals many details about a planet’s characteristics, its diameter, and details of its atmosphere in particular. 

Another type of lift-off (ESA)

By combining a precise measurement of diameter with a measurement of mass, collected by an alternative method, researchers will then be able to determine a planet’s density. This, in turn, can lead to them deducing its composition and internal structure. 

CHEOPS was completed in a short time with an extremely limited budget of around 50-million Euros.

“CHEOPS is the first S-class mission for ESA, meaning it has a small budget and a short timeline to completion,” explains Kate Issak, an ESA/CHEOPS project researcher. “Because of this, it is necessary for CHEOPS to build on existing technology.”

CHEOPS: Informed by the past, informing the future

The project is acting as a kind of ‘middle-man’ between existing exoplanet knowledge and future investigations. It is directed to perform follow-up investigations on 400–500 ‘targets’ found by NASA planet-hunter Transiting Exoplanet Survey Satellite (Tess) and its predecessor, the Kepler observatory. Said targets will occupy a size-range of approximately Earth-Neptune.

Reaching new heights (ESA)

This mission then fits in with the launch of the James Webb Telescope in 2021 and further investigation methods such as the Extremely Large Telescope array in the Chilean desert, set to begin operations in 2026. It will do this by narrowing down its initial targets to a smaller set of ‘golden targets’. Thus, meaning its investigation should help researchers pinpoint exactly what planets in close proximity to Earth are worthy of follow-up investigation. 

“It’s very classic in astronomy that you use a small telescope ‘to identify’, and then a bigger telescope ‘to understand’ — and that’s exactly the kind of process we plan to do,” explains Didier Queloz, who acted as chair of the Cheops science team. “Cheops will now pre-select the very best of the best candidates to apply to extraordinary equipment like very big telescopes on the ground and JWST. This is the chain we will operate.”

Queloz certainly has pedigree when it comes to exoplanets. The astrophysics professor was jointly awarded the 2019 Nobel Prize in Physics for the discovery of the first exoplanet orbiting a Sun-like star with Michel Mayor. 

The first task of the science team operating the satellite, based out of the University of Bern, will be to open the protective doors over the 30 cm aperture telescope — thus, allowing CHEOPS to take its first glimpse of the universe. 

The field of exoplanet research is heating up, and the Trappist-1 system is a prime target for future investigation (University of Bern)

Exoplanet researcher awarded for groundbreaking work

The field of exoplanet research is heating up, and the Trappist-1 system is a prime target for future investigation (University of Bern)
The field of exoplanet research is heating up, and the Trappist-1 system is a prime target for future investigation (University of Bern)

Exoplanet researcher Ignas Snellen — a professor in astronomy at the University of Leiden in the Netherlands — has collected the 2019 Hans Sigrist prize for his innovative work in the field of exoplanet research. The award of the prize to Snellen comes at the conclusion of a year which also marked the Nobel Committee’s recognition of the first observation of an exoplanet orbiting a Sun-like star, awarding its discoverers Michel Mayor and Didier Queloz the 2019 Nobel Prize in Physics.

The message from the scientific community seems to be clear, exoplanet research is a field to watch. With the launch of the CHEOPS satellite, later this month and the James Webb Space Telescope set to launch in 2021, applied science is finally catching up to aspirations held by astronomers for decades–the discovery of more and more diverse worlds outside our solar system.

In addition to this, the tantalizing possibility of catching a fleeting glimpse of a clue that we are not alone in the universe seems closer than ever to realization.

Exoplanet researcher Ignas Snellen accepts his award for groundbreaking research (Robert Lea)

But as Snellen explains, things could have been very different for him, falling into exoplanet research was something of a happy accident: “I was doing very different research, working with galaxies,” he says. “I didn’t really know where my research was going. That’s when I was asked to present a workshop on extrasolar planets.”

Despite the serendipity at play, Snellen says he recognised the potential growth for the young field almost immediately. “I thought ‘wow, what an amazing field!'”

And Snellen’s decision to pursue exoplanet research relates indirectly to Nobel prize winners Mayor and Queloz. “This was in 2001, so exoplanet research was still in its infancy, but the first transiting exoplanet had been discovered as well as a few others.”

Despite the fact that only a handful of exoplanets had been discovered when Snellen began his research in the field less than two decades ago, NASA’s catalog of extrasolar planets now numbers in excess of 4,000. Clearly, this is a stunning illustration of just how rapidly the field has advanced in this relatively short period of time.

Snellen’s work focuses on assessing the atmospheric composition of exoplanets. This possible to do when a planet passes in front of–or ‘transits’– its parent star. The planet’s atmosphere absorbs light from the star at certain wavelengths. As chemical elements absorb and emit light at certain frequencies, the resulting light spectrum forms a distinct ‘fingerprint’ by which they can be identified.

This method of transit spectroscopy holds great promise in terms of identifying potential ‘biomarkers’ such as molecular oxygen, water and carbon monoxide.

As the Hans Sigrist Prize is specifically designated to recognize scientists in the midst of their careers rather than acting as a ‘lifetime achievement’ type award, it is only fitting that its recipient should very clearly have their eyes on future goals. And, fortunately, the future is bright for exoplanet research.

The next generation of telescopes will probe exoplanets more thoroughly than ever before. Clockwise from top: The James Webb Telescope (ESA), The Extremely Large Telescope (ESO) and the CHEOPS telescope (ESA)
The next generation of telescopes will probe exoplanets more thoroughly than ever before. Clockwise from top: The James Webb Telescope (ESA), The Extremely Large Telescope (ESO) and the CHEOPS telescope (ESA)

The ESO’s CHEOPS telescope launches on 17th December with its mission to identify nearby, small rocky exoplanets. Snedden points out the mission’s role as an important first step in the exoplanet research, helping select targets for researchers to further investigate.

But the two projects that Snellen is most excited for and the launch of the James Webb Telescope in 2021 and the completion of the aptly named 39-meter diameter Extremely Large Telescope (ELT) scheduled for completion in 2025.

“At the moment we can only observe the atmospheres of large Jupiter-like gas giants,” he explains. “The James Webb will finally allow us to start examining the atmospheres of smaller, rocky, more Earth-like exoplanets.”

These planets will still differ quite a bit from Earth, elaborates Snellen, explaining that they will, for example, be much hotter than our planet. “The exciting thing is, we don’t yet know if these small rocky planets can actually hold an atmosphere,” Snellen says.

The researcher concludes by pointing out that the seven Earth-like planets of the Trappist-1 system are very likely the first targets for further investigation. An exciting prospect, given that at least three of these planets are believed to exist in that system’s ‘habitable zone’–an area where water can exist as a liquid, a key ingredient for life.

One of the most promising prospects for discovering liquid water in the Trappist-1 system is Trappist-1e, an exoplanet that is slightly denser than Earth. As liquid water requires a temperature that is not too hot and not too cold, and also a certain amount of pressure–the fact that Trappist-1e receives roughly the same amount of radiation from its star as Earth and its gravitational influence exerts a similar pressure, it seems a safe bet to predict liquid water will be found there.

Of course, the concept of discovering liquid water amongst the stars and drawing comparisons to Earth leads, inevitably to the question could any of these planets also host life?

Snellen urges caution, remarking that even if these biomarkers are found, it is still a long way from confirming the ‘Holy Grail’ of exoplanet research: the presence of extraterrestrial life.

“It would be a major clue,” Snellen points out. “But it’s too simple to say ‘OK we have molecular oxygen, this is a sign of life.’ As molecular oxygen is difficult to detect though, by the time we can identify it, we should also be able to see lots of other gases.”

The Hans Sigrist Prize was established in 1994 to recognise mid-career scientists who still have a significant time left in their careers to make further major contributions to their field. Thus far, two of the previous recipients have gone on to become Nobel Prize Laureates later in their careers.

In connection with the prize, Snellen will receive 100,000 CHF–around $100,000–to help further his research. Accepting his prize, Snellen first thanked the team of researchers that have supported him in his research over the past decade.

An artist's impression of the CHEOPS telescope--the ESA's first S-Class project which will search for suitable exoplanets for future investigations (ESA)

Exoplanet telescope CHEOPS gears up for launch day

An artist's impression of the CHEOPS telescope--the ESA's first S-Class project which will search for suitable exoplanets for future investigations (ESA)
An artist’s impression of the CHEOPS telescope–the ESA’s first S-Class project which will search for suitable exoplanets for future investigations (ESA)

The European Space Agency’s (ESA) space telescope CHEOPS (CHaracterising ExOPlanet Satellite) begins its journey into space aboard the Soyuz rocket on December 17th. In preparation for the launch from French Guiana, collaborators in the mission, the ESA, the University of Geneva and the University of Bern held a press conference on the morning of the 5th December.

The gathered experts from the respective agencies discussed the mission–the ESA’s first ‘S-Class’ or small scale project–the international collaboration that brought it together and the role CHEOPS will play in the investigation of Exoplanets and the search for life elsewhere in the universe.

“After over six years of intensive work, I am, of course very pleased that the launch is finally in sight,” Willy Benz, CHEOPS’s principal investigator and professor of astrophysics at the University of Bern states.

The main role of CHEOPS will be to examine the ever-growing catalog of exoplanets, explains David Ehrenreich, CHEOPS Consortium Mission Scientist from the University of Geneva.

A replica of the CHEOPS telescope displayed at a press conference heled by the agencies responsible for the mission (Robert Lea)
A replica of the CHEOPS telescope displayed at a press conference heled by the agencies responsible for the mission (Robert Lea)

This involves selecting what Ehrenreich describes as ‘golden targets’ or exoplanets that missions such as the James Webb Space Telescope (JWST)–set to launch in 2021 from the same site—can follow-up on in order to perform in-depth examinations. As the JWST will search for signs of habitability–mainly indications of water and methane– it is a massive advantage for it to have preselected targets to study.

CHEOPS will enforce this selection process by examining nearby bright stars that are known to host exoplanets–particularly those with planets in a size range of Earth to Neptune. By measuring the transit depths as these planets cross their host star–the sizes of the planets can be accurately ascertained and then the researchers can also calculate their density and in turn, their composition–if they are rocky or gaseous, for example. The mission should also be able to determine if the planets possess deep oceans–believed to be a key component for the development of life.

A Small Mission Can Answer Big Questions

Kate Issak, a CHEOPS project scientist from the ESA explains how the mission–the first part of the Cosmic Vision 2015-2025 program–differs from previous endeavors undertaken by the agency: “CHEOPS is the first S-class mission for ESA, meaning it has a small budget and a short timeline to completion.

“Because of this, it is necessary for CHEOPS to build on existing technology.”

The cost of CHEOPS is an estimated 50-million Euros and it has taken 5 years to complete after being greenlit in 2014. Whilst this may not seem like a small amount of money or a short period of time, the cost and preparation time of the JWST–about 9 billion Euros and 7 years–very much puts both into perspective.

But neither a short timeline to completion or a small budget nor the fact that it mainly bridges the gap between past and future investigations will stop CHEOPS from attempting to answer some of the biggest lingering questions in exoplanet research.

Ehrenreich lays out some of the big questions that CHEOPS may have the potential to tackle, namely:

  • How do planets form?
  • At what rate do planets occur around other stars?
  • What are the compositions of these planets?
  • How do these compositions compare with the compositions of planets in the solar system?
  • Is our solar system unique or common?

And perhaps most interestingly for the general public and scientists alike:

  • Are any of these worlds habitable?

By tackling these questions CHEOPS and the ESA really get to the heart of both space exploration and exoplanet investigation.

CHEOPS: Empathising collaboration

As is fitting for a mission that probes such fundamental ideas as, how common is life in the universe, the ESA is throwing the use of the CHEOPS equipment out to other institutions and researchers.

Whilst 80% of CHEOPS’s operating time will be determined by the ESA’s mission program, Issak explains, the remaining 20% will be devoted to the wider scientific community. The projects and researchers that will be able to make use of this time will be determined based on merit alone.

“CHEOPS will build on the work of the consortium and benefit the scientific community as a whole,” promises Issak.

From Left to Right: David Ehrenreich, Willy Benz, Christian Leumann, Renato Krpoun and Kate Issak discuss the CHEOPS mission at the University of Bern (Robert Lea)
From Left to Right: David Ehrenreich, Willy Benz, Christian Leumann, Renato Krpoun and Kate Issak discuss the CHEOPS mission at the University of Bern (Robert Lea)

The idea of community spirit is built into CHEOPS’s DNA from its genesis, Willy Benz the mission’s principal investigator explains. The project brings together 11 individual nations each of which has made a specific contribution to the equipment aboard the satellite.

Issak adds “CHEOPS is an excellent example of how EU member states can work together.”

The ESA will follow-up on CHEOPS with PLATO (PLAnetary Transits and Oscillation of stars) project in 2026, and ARIEL (Atmospheric Remote-sensing Infrared Exoplanet Large-survey) mission in 2028.

Plato will specialise in the examination of rocky exoplanets orbiting in habitable zones around Sun-like stars, particularly focusing on the potential for these planets to hold liquid water. It will also examine seismic activity in stars–giving insight into the age and evolutionary stage of these planetary systems.

Ariel, meanwhile, will take exoplanet survey and characterisation to a whole new level of detail, enable to perform chemical censuses of a wide variety of planet’s atmospheres.

As the award of this year’s Nobel Prize in Physics to Michel Mayor and Didier Queloz for the discovery of the first exoplanet around a Sun-like star demonstrates, the search for exoplanets and the quest to categorise and understand them is currently one of the hottest research areas in science.

As such CHEOPS puts the ESA at the forefront of the race to discover how common our home planet and the solar system is, and potentially, answer an age-old question: are we alone in the Universe?

Runaway star ejected from the centre of the Milky Way at incredible speed

An artist’s impression of S5-HVS1’s ejection by Sagittarius A*, the black hole at the centre of the galaxy. The black hole and the captured binary partner to S5-HVS1 are seen far away in the left corner of the picture, while S5-HVS1 is in the foreground, speeding away from them. ( James Josephides (Swinburne Astronomy Productions))

Astronomers have discovered a star travelling at an incredible 6 million km/h — ten times faster than the average star — after being ejected by the supermassive black hole at the centre of the Milky Way five million years ago.

Carnegie Mellon University Assistant Professor of Physics Sergey Koposov discovered the star — named S5-HVS1 — as part of the Southern Stellar Stream Spectroscopic Survey (S5).

“The velocity of the discovered star is so high that it will inevitably leave the galaxy and never return,” said Douglas Boubert from the University of Oxford, a co-author of the study.

An artist’s impression of the ejection mechanism of a star by a supermassive black hole. Credit: James Josephides (Swinburne Astronomy Productions)

S5-HVS1 — located in the constellation of Grus — is part of a population of objects known as ‘high-velocity stars’ (HVSs). These stars sparked curiosity amongst astronomers after the first example was discovered in 2005. In the next 14 years, many more examples of HVSs have been uncovered.

But, even amongst these aptly-named stars, S5-HVS1 is exceptional for its high speed. The star’s close passage to Earth at a mere (in astronomical terms) 2.9 x 10⁴ light-years away, also makes it somewhat unique.

Armed with information about the runaway star’s blazing speed coupled with its close proximity has allowed astronomers to track its trajectory back to the centre of the Milky Way and the supermassive black hole — Sagittarius A* (Sgr A*) — which dwells there.

“This is super exciting, as we have long suspected that black holes can eject stars with very high velocities. However, we never had an unambiguous association of such a fast star with the galactic centre,” says Koposov, the lead author of this work and member of Carnegie Mellon’s McWilliams Center for Cosmology. “We think the black hole ejected the star with a speed of thousands of kilometres per second about five million years ago.

“This ejection happened at the time when humanity’s ancestors were just learning to walk on two feet.”

A bad break-up?

So how on Earth did S5-HVS1 come to be travelling at such an extraordinary speed?

Astronomers believe that the star was once part of a binary system with a companion star. It was ejected from this partnership after both stars’ orbits strayed too close to Sgr A*. Whilst its partner was captured by the incredible gravitational attraction of the supermassive black hole, the gravitational struggle tore S5-HVS1 free and launched it on its rapid journey.

The location of S5-HVS1 on the sky and the direction of its motion. The star is flying away from the galactic centre, from which it was ejected 5 million years ago. ( Sergey Koposov)

This process is known as the ‘Hills mechanism’ and was first suggested by astronomer Jack Hills thirty years ago and has long been considered as a likely mechanism for the origins of high-velocity stars.

“This is the first clear demonstration of the Hills Mechanism in action,” points out Ting Li from Carnegie Observatories and Princeton University, and leader of the S5 Collaboration. “Seeing this star is really amazing as we know it must have formed in the galactic centre, a place very different from our local environment.

“It is a visitor from a strange land.”

An exceptional observation

The astronomers made the discovery of S5-HVS1 was made with 3.9-metre Anglo-Australian Telescope (AAT) near Coonabarabran, NSW, Australia. The team was only able to assess the true speed of the star and details of its incredible journey when these observations were coupled with further data from the European Space Agency’s Gaia satellite.

“The observations would not be possible without the unique capabilities of the 2dF instrument on the AAT,” adds Daniel Zucker, an astronomer at Macquarie University in Sydney, Australia, and a member of the S5 executive committee. “It’s been conducting cutting-edge research for over two decades and still is the best facility in the world for our project.”

The team’s results are published in the journal Monthly Notices of the Royal Astronomical Society.

“I am so excited this fast-moving star was discovered by S5,” says Kyler Kuehn, at Lowell Observatory and a member of the S5 executive committee. “While the main science goal of S5 is to probe the stellar streams — disrupting dwarf galaxies and globular clusters — we dedicated spare resources of the instrument to searching for interesting targets in the Milky Way, and voila, we found something amazing for ‘free.’

“With our future observations, hopefully, we will find even more!”

Original research:

Artist's composition of a volcanic exo-Io undergoing extreme mass loss. The hidden exomoon is enshrouded in an irradiated gas cloud shining in bright orange-yellow, as would be seen with a sodium filter. Patches of sodium clouds are seen to trail the lunar orbit, possibly driven by the gas giant's magnetosphere. (© University of Bern, Illustration: Thibaut Roger)

Astronomers find clues of a volcanically active exomoon

Artist’s composition of a volcanic exo-Io undergoing extreme mass loss. The hidden exomoon is enshrouded in an irradiated gas cloud shining in bright orange-yellow, as would be seen with a sodium filter. Patches of sodium clouds are seen to trail the lunar orbit, possibly driven by the gas giant’s magnetosphere. (© University of Bern, Illustration: Thibaut Roger)

A rocky extrasolar moon brimming with lava could orbit a planet 550 light-years from Earth, astronomers led by researchers from Bern University have discovered. 

The volcanically active exomoon could be hidden in the exoplanet system WASP-49b, orbiting a hot giant planet in the inconspicuous constellation of Lepus, underneath the bright Orion constellation.

The researchers describe the exomoon as an ‘extreme’ version of Jupiter’s moon Io — the most volcanically active body in our own solar system. Thus, painting a picture of an exotic and dangerous world — an ‘exo-Io’. 

Apurva Oza, a postdoctoral fellow at the Physics Insitute of the University of Bern and associate of the NCCR PlanetS, describes the exomoon, comparing it to a famous sci-fi setting: “It would be a dangerous volcanic world with a molten surface of lava — a lunar version of close-in Super-Earths like 55 Cancri-e. 

“A place where Jedis go to die, perilously familiar to Anakin Skywalker.”

More than a grain of sodium. Uniting theory and circumstantial evidence.

Astronomers have yet to discover a moon beyond our solar system meaning that the researchers base their suspicions of the existence of this exo-Io on circumstantial evidence — namely sodium gas in WASP-49b at an unusually high-altitude. 

Oza explains: “The neutral sodium gas is so far away from the planet that it is unlikely to be emitted solely by a planetary wind.

“The sodium is right where it should be.”

Comparing this feature to observations of the Jupiter and Io system using low-mass calculations demonstrated to the team that an exo-Io could, indeed, be a plausible mechanism for sodium at WASP-49b. 

The theory that large amounts of sodium around an exoplanet could point to a hidden moon or a ring of material was advance by Bob Johnson and Patrick Huggins in 2006. Following this, researchers from the University of Virginia calculated that a three-body system comprised of a star, close giant planet and a moon could remain stable for billions of years. 

Oza took these theoretical predictions to form the basis of he and his colleagues’ work — published in the Astrophysical Journal. 

The astrophysicist explains: “The enormous tidal forces in such a system are the key to everything.

“The energy released by the tides to the planet and its moon keeps the moon’s orbit stable, simultaneously heating it up and making it volcanically active.”

The researchers also demonstrate in their study that a small rocky moon would eject more sodium and potassium into space via this extreme volcanism than a large gas planet. This would especially be the case at high altitudes. 

These emissions can then be identified by astronomers using the technique of spectroscopy. These particular elements are particularly useful to astronomers. 

Oza adds: “Sodium and potassium lines are quantum treasures to us astronomers because they are extremely bright.

“The vintage street lamps that light up our streets with yellow haze, is akin to the gas we are now detecting in the spectra of a dozen exoplanets.”

When comparing their calculations with actual observations of sodium and potassium, the team found five candidate systems where a hidden exomoon could survive thermal evaporation. In the case of WASP-49b, the best explanation for the observed data was the presence of an exo-Io. 

This isn’t the only explanation, however. As mention above, the observations of sodium at high altitudes could instead indicate the exoplanet is surrounded by a ring of material — most likely ionised gas. 

Oza admits that the team need to find more clues, and as such, are relying on future observations with both ground and space-based telescopes. Also, as a few of these exo-Ios could eventually be destroyed as a result of extreme mass-loss, the team also want to search for evidence of such destruction. 

Oza concludes: “While the current wave of research is going towards habitability and biosignatures, our signature is a signature of destruction.

“The exciting part is that we can monitor these destructive processes in real-time, like fireworks.”

Original research:

Illustration by Wendy Kenigsberg/Matt Fondeur/Cornell University

Biofluorescence shining light on the search for alien life

The use of ultraviolet flares from red suns and biofluorescence may provide astronomers with vital life signs in the universe

Illustration by Wendy Kenigsberg/Matt Fondeur/Cornell University
Illustration by Wendy Kenigsberg/Matt Fondeur/Cornell University

A new method of searching for life in the cosmos has been pioneered by astronomers from Cornell University.

The team propose that astronomers could utilise harsh ultraviolet radiation flares from red suns — once thought to destroy surface life on planets — to assist in the discovery of hidden biospheres. The team’s study — published in the journal Monthly Notices of the Royal Astronomical Society — suggests that ultraviolet radiation could trigger biofluorescence — a protective glow — from life on exoplanets.

Jack O’Malley-James, a researcher at Cornell’s Carl Sagan Institute and the study’s lead author, says: “This is a completely novel way to search for life in the universe.

“Just imagine an alien world glowing softly in a powerful telescope.”

Biofluorescence, similar to that found in coral, could be used by astronomers to search for life (S.E.A. Aquarium)

Some undersea coral on Earth use a similar form of biofluorescence that the team intend to utilise in the search for life. The coral does this in order to render the sun’s harmful ultraviolet radiation into harmless visible wavelengths, in the process, creating a beautiful radiance.

“Maybe such life forms can exist on other worlds too, leaving us a telltale sign to spot them,” points out Lisa Kaltenegger, associate professor of astronomy and director of the Carl Sagan Institute.

She points out that in our search for exoplanets, we have searched for ones which look like our own planet. This research plays off the idea the biofluorescence may not have evolved on Earth exclusively.

In fact, as this is a form of defence from harsh UV radiation, logic suggests that its usefulness — and thus, the chance of development — would be increased around stars where UV flares are commonplace.

A large fraction of exoplanets — planets beyond our solar system — reside in the habitable zone of M-type stars. This type of star — the most commonly found in the universe — frequently flare, and when those ultraviolet flares strike their planets, biofluorescence could paint these worlds in beautiful colours.

The next generation of Earth- or space-based telescopes can detect the glowing exoplanets — should they exist.

Ultraviolet rays are transformed into less-energetic and therefore less harmful wavelengths through a process called “photoprotective biofluorescence.” This should leave a very specific signal which astronomers can search for.

Kaltnegger continues: “Such bio fluorescence could expose hidden biospheres on new worlds through their temporary glow when a flare from a star hits the planet.”

The astronomers used emission characteristics of common coral fluorescent pigments from Earth to create model spectra and colours for planets orbiting active M stars to mimic the strength of the signal and whether it could be detected for life.

Proxima b — a potentially habitable world found orbiting the active M star Proxima Centauri in 2016 could qualify as a target for such a search. The rocky exoplanet has been one of the most optimal space travel destinations due to the proximity of the star it orbits — although such jaunts are a concern for the far-future.

Jack O’Malley-James, continues: “These biotic kinds of exoplanets are very good targets in our search for exoplanets, and these luminescent wonders are among our best bets for finding life on exoplanets.”

Large, land-based telescopes that are being developed now for 10 to 20 years into the future may be able to spot this glow.

Kaltenegger concludes: “It is a great target for the next generation of big telescopes, which can catch enough light from small planets to analyze it for signs of life, like the Extremely Large Telescope in Chile.”

Original research: Biofluorescent Worlds II: Biological Fluorescence Induced by Stellar UV Flares, a New Temporal Biosignature. Jack T O’Malley-James, Lisa Kaltenegger.

Birthplace of giant planets: Monash astrophysicists discover a baby planet sculpting a disc of gas and dust. Credit: ESO/ALMA.

‘Baby’ planet two to three times the size of Jupiter discovered

It may be an infant, but that doesn’t mean it’s small. Researchers have discovered a new ‘baby’ planet, at least twice the size of Jupiter, carving a path through a stellar nursery. 

Astrophysicists from Monash University have used the ALMA telescope in Chile to discover a ‘baby’ planet inside a protoplanetary disc. But despite being a youngster, this infant is still between two to three times the mass of Jupiter — the most massive planet in our solar system. 

Birthplace of giant planets: Monash astrophysicists discover a baby planet sculpting a disc of gas and dust. Credit: ESO/ALMA.

The giant ‘baby’ was found inside in the middle of a gap in the gas and dust that forms the planet-forming disc around the young star HD97048. The study — published in Nature Astronomy — is the first to provide an origin of these gaps in protoplanetary discs — also known as ‘stellar nurseries’ because they act as the birthplaces for planets— which have thus far puzzled astronomers. 

“The origin of these gaps has been the subject of much debate,” says the study’s lead author, Dr Christophe Pinte, an ARC Future Fellow at the Monash School of Physics and Astronomy. “Now we have the first direct evidence that a baby planet is responsible for carving one of these gaps in the disc of dust and gas swirling around the young star.”

The team discovered the new planet by mapping the flow of gas around HD97048 — a young star not yet on the main sequence, which sits in the constellation Chamaeleon located over 600 light-years from Earth. 

Observing the flow in this material, the team hunted for areas in which the flow was disturbed, in a similar way to disturbance a submerged rock would cause in a stream flowing over it. They were able to ascertain the planet’s size by recreating this ‘bump’ or ‘kink’ in the flow using computer models. 

Using the same method of locating ‘bumps’ in gas flow around young stars, the team previously discovered a similar new ‘baby’ planet around another young star roughly a year ago. Those findings were published in the Astrophysical Journal Letters.

That initial discovery — found in the stellar nursery around HD163296 360 light-years from Earth — was the first of its kind and provided a ‘missing link’ in scientists understanding of planet formation.

These two studies add to what is only a small collection of known ‘baby’ planets. 

“There is a lot of debate about whether baby planets are really responsible for causing these gaps,” says Associate Professor Daniel Price, the study’s co-author and Future Fellow at the school. “Our study establishes for the first time a firm link between baby planets and the gaps seen in discs around young stars.”

Original research:

Ancient galaxies from the study are visible to ALMA (right) but not to Hubble (left). Credit: © 2019 Wang et al.

‘Hidden’ ancient galaxies discovery may redefine our understanding of the Universe

The discovery of 39 ‘hidden’ ancient galaxies urges scientists to rethink their theories of fundamental aspects of the Universe — including supermassive black holes, star formation rates, and the ever-elusive, dark matter.

Ancient galaxies from the study are visible to ALMA (right) but not to Hubble (left). Credit: © 2019 Wang et al.

In an unprecedented discovery of astronomers, researchers have utilised the combined power of a multitude of observatories across the globe to discover a vast array of 39 previously hidden galaxies.

The finding — described by the researchers from the University of Tokyo as a ‘treasure trove’ — is the first multiple discoveries of this kind. But the finding is significant for more than its size alone.

In addition to containing a wealth of newly discovered ancient galaxies, an abundance of this particular type of galaxy suggests that scientists may have to refine current models of the universe.

This is because our current understanding of the universe and how it formed is built upon observations of galaxies in ultraviolet light. But observations in these wavelengths under-represent the most massive galaxies — those with high dust content and crucially, the most ancient.

This means that a discovery of such galaxies — such as the one just made — must force us to reconsider the rates of star formation in the early universe. The study explains that the population of stars discovered may mean that star formation rates were actually ten times greater in early epochs than previous estimates held.

There are also particular ramifications for our understanding of both supermassive black holes and their distribution, and for the concept of dark matter — the elusive substance which makes up 80% of the matter in the universe.

Despite the wealth of astronomical data that has become available to scientists since the launch of the Hubble Space Telescope, researchers at the Institute of Astronomy in Toyko were aware there were things that Hubble simply couldn’t show us. It was these things — fundamental pieces of the cosmic puzzle — that they wanted to investigate.

They achieved this by unifying different observatories, using them to look more deeply in the Universe than Hubble alone could do. This is what led them to this huge collection of galaxies.

Researcher Tao Wang describes the uniqueness and magnitude of the team’s discovery: “This is the first time that such a large population of massive galaxies was confirmed during the first two billion years of the 13.7-billion-year life of the universe.

“These were previously invisible to us.”

Wang continues: “This finding contravenes current models for that period of cosmic evolution and will help to add some details, which have been missing until now.”

A different view of the universe

Wang explains that if we could see these galaxies and the light they shed, our view from the Milky way would be significantly different: “For one thing, the night sky would appear far more majestic. The greater density of stars means there would be many more stars close by appearing larger and brighter.

“But conversely, the large amount of dust means farther-away stars would be far less visible, so the background to these bright close stars might be a vast dark void.”

The galaxies have been difficult to see from Earth due to how faint they are. Were we able to see these stars, their density would make the night sky majestic, Wang says.

The light from these galaxies also has to battle extinction — the absorption of light) by intervening interstellar dust clouds. The light from the galaxies also has to travel great distances meaning the wavelength is redshifted by the expansion of the universe making it even less visible.

Professor Kotaro Kohno. Credit: © 2019 Rohan Mehra — Division of Strategic Public Relations

Professor Kotaro Kohno explains that this phenomenon is how the galaxies escaped Hubble’s gaze: “The light from these galaxies is very faint with long wavelengths invisible to our eyes and undetectable by Hubble.

“So we turned to the Atacama Large Millimeter/submillimeter Array (ALMA), which is ideal for viewing these kinds of things. I have a long history with that facility and so knew it would deliver good results.”

This redshift due to cosmic expansion does have its advantages, however. It allows astronomers to estimate not just the distances to the galaxies in question, but it also allows them to calculate just how long ago the light was emitted.

The hidden implications of these hidden galaxies

The team’s finding is so controversial and poses such a radical rethink that they found their fellow astronomers were initially reluctant to believe they had found what they claimed.

A few of the 66 radio telescope antennas that make up ALMA. Credit: © 2019 Kohno et al.

Wang explains: “It was tough to convince our peers these galaxies were as old as we suspected them to be. Our initial suspicions about their existence came from the Spitzer Space Telescope’s infrared data.

“But ALMA has sharp eyes and revealed details at submillimeter wavelengths, the best wavelength to peer through dust present in the early universe. Even so, it took further data from the imaginatively named Very Large Telescope in Chile to really prove we were seeing ancient massive galaxies where none had been seen before.”

The discovery has the potential to reshape our ideas of the supermassive black holes that scientists currently believe nestle at the centre of most galaxies.

Kohno elaborates: “The more massive a galaxy, the more massive the supermassive black hole at its heart.

“So the study of these galaxies and their evolution will tell us more about the evolution of supermassive black holes, too.”

Kohno also explains that some ideas regarding dark matter may have to be revised, too: “Massive galaxies are also intimately connected with the distribution of invisible dark matter. This plays a role in shaping the structure and distribution of galaxies. Theoretical researchers will need to update their theories now.”

In addition to the potential shake up the team believes that their findings may already present, they expect more surprises to come.

Wang concludes: These gargantuan galaxies are invisible in optical wavelengths so it’s extremely hard to do spectroscopy, a way to investigate stellar populations and chemical composition of galaxies. ALMA is not good at this and we need something more.

“I’m eager for upcoming observatories like the space-based James Webb Space Telescope to show us what these primordial beasts are really made of.”

Original research: T. Wang, C. Schreiber, D. Elbaz, Y. Yoshimura, K. Kohno, X. Shu, Y. Yamaguchi, M. Pannella, M. Franco, J. Huang, C.F. Lim & W.H. Wang. A dominant population of optically invisible massive galaxies in the early Universe. Nature. DOI: 10.1038/s41586–019–1452–4

Einstein’s General Relativity passes the test at the centre of our Galaxy

Measurements of a star passing close to the supermassive black hole at the centre of the Milky Way confirms the predictions of Einstein’s theory of general relativity in a high gravity environment.

An artist visualization of the star S0–2 as it passes by the supermassive black hole at the Galactic centre. As the star gets closer to the supermassive black hole, light it emits experiences a gravitational redshift that is predicted by Einstein's General Relativity. By observing this redshift, we can test Einstein's theory of gravity (Nicole R. Fuller, National Science Foundation)

An artist visualization of the star S0–2 as it passes by the supermassive black hole at the Galactic centre. As the star gets closer to the supermassive black hole, light it emits experiences a gravitational redshift that is predicted by Einstein’s General Relativity. By observing this redshift, we can test Einstein’s theory of gravity (Nicole R. Fuller, National Science Foundation)

A detailed study of a star orbiting the supermassive black hole at the centre of our Galaxy, reveals that Einstein’s theory of general relativity is accurate in its description of the behaviour of light struggling to escape the gravity around this massive space-time event.

The analysis — conducted by Tuan Do, Andrea Ghez and colleagues — involved detecting the gravitational redshift in the light emitted by a star closely orbiting the supermassive black hole known as Sagittarius A*. The redshift was measured as the star reached the closest point in its orbit — which has a duration of 16 years — to the black hole.

Lasers from the two Keck Telescopes propagated in the direction of the Galactic centre. Each laser creates an artificial star that can be used to correct for the blurring due to the Earth’s atmosphere. (Ethan Tweedie) 

Lasers from the two Keck Telescopes propagated in the direction of the Galactic centre. Each laser creates an artificial star that can be used to correct for the blurring due to the Earth’s atmosphere. (Ethan Tweedie)

The team found that the star experienced gravitational redshift — which occurs when light is stretched to longer wavelengths and towards the red ‘end’ of the electromagnetic spectrum by the effect of gravity — as it gets closer to the black hole,  conforming to Einstein’s theory of general relativity and its predictions regarding gravity.

At the same time, the results defy predictions made by the Newtonian theory, which has no explanation for gravitational redshift.

Ghez says: “(The findings are) a transformational change in our understanding about not only the existence of supermassive black holes but the physics and astrophysics of black holes.”

The major difference between general relativity and the Newtonian calculation of gravity is, that whereas Newton envisioned gravity as a force acting between physical objects, Einstein’s theory saw gravity as a geometric phenomenon.

The presence of mass ‘curves’ space it occupies. Physical objects, including light, must then follow this curvature. As John Wheeler infamously put it: “matter tells space how to curve, space tells matter how to move.”

Testing relativity in regions of high gravity

Image of the orbits of stars around the supermassive black hole at the centre of our galaxy. Highlighted is the orbit of the star S0–2. This is the first star that has enough measurements to test Einstein’s General Relativity around a supermassive black hole. [Credit: Keck/UCLA Galactic Center Group]

Image of the orbits of stars around the supermassive black hole at the centre of our galaxy. Highlighted is the orbit of the star S0–2. This is the first star that has enough measurements to test Einstein’s General Relativity around a supermassive black hole. [Credit: Keck/UCLA Galactic Center Group]

The new research resembles an analysis conducted last year by the GRAVITY collaboration, except in this new expanded analysis, the team report novel spectra data.

Although general relativity has been thoroughly tested in relatively weak gravitational fields — such as those on Earth and in the Solar System—before last year, it had not been tested around a black hole as big as the one at the centre of the Milky Way.

Observations of the stars rapidly orbiting Sagittarius A *provide a method for general relativity to be evaluated in an extreme gravitational environment.

Do explains why these kind of tests are important:

“We need to test GR in extreme environments because that’s where we think the theory might break down.”

“If we can see which predictions from general relativity have deviations, that gives us clues as to how to build a better model of gravity.”

A figure showing the challenges the Ghez team had in processing decades of image data and spectroscopy input to follow the star S0–2. (Zina Deretsky, National Science Foundation)

A figure showing the challenges the Ghez team had in processing decades of image data and spectroscopy input to follow the star S0–2. (Zina Deretsky, National Science Foundation)

To obtain their results, the team analyzed new observations of the star S0–2 as it made its closest approach to the enormous black hole in 2018. They then combined this data with measurements Ghez and her team have made over the last 24 years.

The team has many avenues of investigations available to them from here, Tuan tells me.

He continues: “Two of them I’m excited about are testing space-time around the black hole by looking at the orbit of the star S0–2.”

“GR predicts that the orbit should precess, or rotate, meaning that it won’t come back where it started.”

The team should also be able to start using more stars other than S0–2 for these tests as the time baseline of observations increase and technology improves

Do concludes: “ These measurements open a new era of GR tests at the Galactic centre so it’s very exciting.”

This research appears in the 26 July 2019 issue of Science.

Why the SpaceX satellite fleet could spell major headaches for astronomers

In 2015, the world got understandably excited as SpaceX mastermind Elon Musk announced the launch of a new satellite fleet that would give the world faster and cheaper internet. But as the first few satellites were launched, it made a lot of astronomers unhappy.

The constellation, which so far consists of 60 satellites but is set to be expanded to 12,000, add more clutter and significantly reduce our view of the cosmos, potentially dealing an important blow to many, many space surveys.

Screenshot taken from a video shot by Marco Langbroek with a group of SpaceX Starlink satellites passing over the Netherlands on May 24, 2019.

When the first satellites were launched, the event was tracked all around the world. Astronomer Marco Langbroek noted on his blog a calculation of where the satellites would be orbiting. He set up his camera and patiently waited, but not for long: he quickly observed a string of bright dots flying across the sky. The satellites were so bright that they were even visible to the naked eye in certain instances prompting some people to UFO sightings.

Sure enough, their brightness has diminished partly as they stabilized into orbit, but for astronomers, this was a clear message: observations are bound to get more difficult, and there’s going to be a lot more objects in the way.

To get a sense of the current situation, there are currently 2,100 active satellites orbiting our planet. If 12,000 are added by SpaceX alone, it would add an unprecedented level of visual clutter for astronomers — and SpaceX is just one of the companies who want to put internet satellites into orbit.

“People were making extrapolations that if many of the satellites in these new mega-constellations had that kind of steady brightness, then in 20 years or less, for a good part of the night anywhere in the world, the human eye would see more satellites than stars,” Bill Keel, an astronomer at the University of Alabama, told AFP.

Jonathan McDowell of the Harvard Smithsonian Center for Astrophysics also adds that at least during some parts of the year, things will get a bit more problematic for astronomers.

“So, it’ll certainly be dramatic in the night sky if you’re far away from the city and you have a nice, dark area; and it’ll definitely cause problems for some kinds of professional astronomical observation.”

SpaceX’s declared goal is a lofty one:  to provide broadband internet connectivity to underserved areas of the planet and offer cheaper, more reliable service to all the world. The cashflow received from this venture would help the company advance its Mars flight plans, helping mankind achieve its space exploration dreams. Yet at the same time, this is placing a hurdle in the way of astronomers.

If there’s anything we can learn from this story, is that things are most often complex, and even with good intentions, planetary-scale projects can have important side-effects which need to be accounted for.

Universe has 2 trillion galaxies, 20 times more than we thought, new study claims

We may have dramatically underestimated what lies in the Universe.

Image via NASA/HUBBLE.

Try for a moment to ponder this: there are two trillion galaxies in the universe. The Milky Way alone has over 100 million stars. Can you even wrap your head around that? The sheer number of stars in the Universe is mind-bending, as is the possibility for life. We’ve just started scratching the surface.

“It boggles the mind that over 90% of the galaxies in the universe have yet to be studied,” commented Christopher Conselice of the University of Nottingham, who led this study. he said in a statement.

NASA snaps beautiful picture of Mars as it inches over towards Earth

NASA astronomers captured a beautiful image of Mars on May 12, when the planet was just 50 million miles away from Earth. Bright snow-capped polar regions and rolling clouds above the rusty landscape show that Mars is a dynamic, seasonal planet, not an inert rock barreling through space.

This picture was taken just a few days before the Mars opposition on May 22, when the red planet and the sun will be on exact opposite side of the Earth. Mars circles around the sun on an elliptical orbit, and its approaches to Earth range from 35 to 63 million miles. From now to May 30 Mars will inch in ever closer to 46.8 million miles from us — the closest this planet has been to Earth for the last 11 years. Being illuminated directly by the sun, Mars is especially photogenic and NASA used this opportunity to capture a beautiful shot of the planet.

The most eye-catching features are the thick blankets of clouds, clinging to the planet’s thin atmosphere. They can be seen covering large parts of the planet, including the southern polar cap. The western limbs are early morning clouds and haze, while the eastern part is an afternoon cloud extending for more than 1,000 miles at mid-northern latitudes. The northern polar cap is barely visible, as it’s now late summer in that hemisphere.
Mars Near 2016 Oppostion (Annotated)

The overcast Syrtis Major Planitia is an ancient shield volcano, now inactive. It was one of the first structures charted on the planet’s surface by seventeenth century observers. Huygens used this feature as a reference point to calculate the rotation speed of Mars — one day on the red planet clocking in at 24 hours and 37 minutes.

Hellas Planitia basin extends to the south of Syrtis Major. At about 1,100 miles across and nearly five miles deep, you’d think it’s a tectonic depression, but it was actually formed 3.5 billion years ago when a huge asteroid crashed into Mars. The planet had its fair share of meteorite impacts throughout the ages, as Arabia Terra can attest — this 2,800 mile upland region is dotted with craters and heavily eroded. Dry river canyons wind through the region, testament to rivers that once flowed into the large northern lowlands.

The long, dark ridges running along the equator south of Arabia Terra, are known as Sinus Sabaeus (to the east, not pictured) and Sinus Meridiani (to the west). These areas are covered by dark bedrock and sand ground down from ancient lava flows and other volcanic features. The sand is coarser and less reflective than the fine dust enveloping the planet, making them stand out.

Several NASA Mars robotic missions, including Viking 1 (1976), Mars Pathfinder (1997) and the still-operating Opportunity Mars rover have landed on the hemisphere visible in this picture. Spirit and Curiosity Mars rovers landed on the opposite side of the planet.

All images provided by Hubble Site.

Hubble captures the death of a star, offering a glimpse of our sun’s final days

A spectacular image captured by the Hubble Space Telescope’s Wide Field Planetary Camera 2 (WFPC2) gives us a glimpse into how the Sun will look at its death.

Launched in 1990, the Hubble Space Telescope is among the most powerful and versatile tools astronomers have at their disposal even to this day. On Monday, the European Space Agency released a photo taken bu Hubble’s WFPC2 of the planetary nebula Kohoutek 4-55 that reminds us that nothing under the sun lasts forever — but the star itself also abides by that saying.

Five billion years from now, this is most likely how the sun will look. By then, the star is anticipated to be on the throes of death.
(Photo : NASA, ESA and the Hubble Heritage Team (STScI/AURA). Acknowledgment: R. Sahai and J. Trauger (JPL))

This photo is a composite image of three individual shots taken at specific wavelengths, to allow researchers to distinguish light from particular gas atoms. The red wavelength corresponds to nitrogen gas, blue to oxygen and green signifies hydrogen.

At the center of the colorful swirl of gas is a star, about the same size as the sun, on the throes of death. The star is about as massive as the sun. As stars age and consume their fuel, the nuclear reactions that produces their light and warmth start to slow down; The irregular energy patterns of energy production causes aging stars to pulsate irregularly making them eject their outer layers.

As the outer layers of gases are released the star’s core is revealed, giving of massive amounts of UV light. That radiation is responsible for the glow of the gas and the nebula’s beauty.

The sun is anticipated to behave in a similar manner to the Kohoutek 4-55 star,ejecting its outer layers to reveal its core — until it gradually cools down into a white dwarf. The image allows scientists a glimpse the distant future of our sun, expected to die off 5 billion years from now.

“By that time, Earth will be long gone, burnt to a crisp as the Sun dies,” ESA wrote. “But the beauty of our star’s passing will shine across the Universe.”

Hubble’s ‘heir’ is coming together

NASA is very close to reaching a milestone in the construction of the James Webb Space Telescope (JWST), Hubble’s successor that will be launched in 2018.

The telescope will consist of 18 mirror segments when it’s completed. Each segment can be independently adjusted to bring the starlight into focus.
David Higginbotham/Emmett Given/MSFC/NASA

Engineers have almost completely assembled the giant mirror, with a collecting area about five times larger (25 square meters) than Hubble’s – despite being twice as light. When complete, the mirror will look like a giant satellite dish – one that’s two stories high.

“So far, everything — knock on wood — is going quite well,” says Bill Ochs, the telescope’s project manager at Goddard Space Flight Center in Maryland.

Comparison between Hubble’s and James Webb’s mirrors. Wikipedia.

This has been the fastest and most cursive part of the building schedule in what was otherwise a project with many hurdles and delays. This isn’t unexpected though. When Hubble’s construction started in 1972, it had an estimated cost of $300 million – but when it finally went in space in 1990, it cost four times more. But just like Hubble was revolutionary (and still is), so too will James Webb be.

The largest NASA astrophysics mission of its generation, JWST will offer unprecedented resolution and sensitivity from long-wavelength (orange-red) visible light, through near-infrared to the mid-infrared. It will be able to capture light from the first stars and galaxies in the Universe, from billions of light years across.

It will also probe the atmospheres of potentially habitable planets, providing more information on their habitability. It’s bigger and better.

“Every time we build bigger or better pieces of equipment, we find something astonishing,” he says.

Full scale James Webb Space Telescope model at South by Southwest in Austin. Wikipedia.

Unfortunately, the construction of something so large and innovative is bound to have some delays and cost extensions. The first estimates suggested the observatory would cost $1.6 billion and launch in 2011. Now, NASA has scheduled the telescope for a 2018 launch and that seems to be well on track. They even have a generous margin for an October 2018 launch.

“We keep our fingers crossed, but things have been going tremendously well,” said Nasa’s JWST deputy project manager John Durning. “We have eight months of reserve; we’ve consumed about a month with various activities,” he added.