Tag Archives: Vera C Rubin observatory

Ten areas in the sky were selected as “deep fields” that the Dark Energy Camera imaged several times during the survey, providing a glimpse of distant galaxies and helping determine their 3D distribution in the cosmos.

Astronomers map over 100 million galaxies to crack dark matter and dark energy puzzle

The Dark Energy Survey (DES) is an ambitious cosmological project that aims to map hundreds of millions of galaxies. In the process, the project will detail hundreds of millions of galaxies, observe thousands of supernovae, map the cosmic web that links galaxies, all with the aim of investigating the mysterious force that is causing the Universe to expand at an accelerating rate.

Using the 570-megapixel Dark Energy Camera on the National Science Foundation’s Víctor M. Blanco 4-meter Telescope at Cerro Tololo Inter-American Observatory (CTIO), Chile, the DES has observed a map of galaxy distribution and morphology that stretches 7 billion light-years and captures 1/8 of the sky over Earth.

Ten areas in the sky were selected as “deep fields” that the Dark Energy Camera imaged several times during the survey, providing a glimpse of distant galaxies and helping determine their 3D distribution in the cosmos.
Ten areas in the sky were selected as “deep fields” that the Dark Energy Camera imaged several times during the survey, providing a glimpse of distant galaxies and helping determine their 3D distribution in the cosmos. The image is teeming with galaxies — in fact, nearly every single object in this image is a galaxy. Some exceptions include a couple of dozen asteroids as well as a few handfuls of foreground stars in our own Milky Way. (Dark Energy Survey/DOE/FNAL/DECam/CTIO/NOIRLab/NSF/AURA)



Now new results from the DES which collects the work of an international team of over 400 scientists from over 25 institutions from countries including the US, UK, France, Spain, Brazil, and Australia, are in. The findings are detailed in a ground-breaking series of 29 papers and comprises of data collected during the DES’ first three years of operation providing the most detailed description of the Universe’s composition and expansion to date.

The Víctor M. Blanco 4-meter Telescope is seen here at night at Cerro Tololo Inter-American Observatory, with trails of stars high above it. On this telescope is the 570-megapixel Dark Energy Camera — one of the most powerful digital cameras in the world. The Dark Energy Camera was designed specifically for the Dark Energy Survey. It was funded by the Department of Energy (DOE) and was built and tested at DOE’s Fermilab. (DOE/FNAL/DECam/R. Hahn/CTIO/NOIRLab/NSF/AURA)

The survey was conducted between 2013 to 2019 cataloging hundreds of millions of objects, with the three years of data covered in these papers alone containing observations of at least 226 million galaxies observed over 345 nights.

The fact that some of these galaxies are close to the Milky Way and others are much more distant–up to 7 billion light-years away– gives researchers an excellent picture of the evolution of the Universe over around half of its lifetime.

The results seem to confirm the standard model of cosmology, currently the best-evidenced theory of the Universe’s composition and evolution which suggests the Universe was created in a ‘Big Bang’ event and has a composition of 5% ordinary or baryonic matter, 27% dark matter, and 68% dark energy.

The snapshot of the Universe provided by the DES does seem to show that the Universe is less ‘clumpy’ than current cosmological models suggest, however.

Illuminating the Dark Universe

The fact that the ‘Dark Universe’ consists of 95% of the matter and energy in the known cosmos means that there are huge gaps in our understanding of the evolution of the Universe, its past, present, and its future.

These gaps include the nature of dark matter, whose gravitational influence holds galaxies together, and dark energy, the force that is expanding space between the galaxies driving them apart at an accelerating rate.

These effects seem to be in opposition, with one holding matter together and the other working upon space itself to drive matter apart. And it is this cosmic struggle that shapes the Universe which the DES aimed to investigate.

There are two key phenomena which the survey used to do this. Studying ‘the cosmic web’ that links galaxies together in clusters and loose associations gives hints at the distribution and influence of dark matter.

The Dark Energy Survey camera (DECam) at the SiDet clean room. The Dark Energy Camera was designed specifically for the Dark Energy Survey. It was funded by the Department of Energy (DOE) and was built and tested at DOE’s Fermilab. (DOE/FNAL/DECam/R. Hahn/CTIO/NOIRLab/NSF/AURA)



The second phenomenon used by the DES is the bending of light as it travels past curvatures in spacetime created by objects of tremendous mass like galaxies. This effect predicted by Einstein’s theory of gravity–general relativity–is known as ‘gravitational lensing.’

The DES relied on a form of this effect called ‘weak gravitational lensing’ to assess how dark matter is distributed across the Universe, thus inferring its ‘clumpiness.’

Weak graviational lensing was one ofthe phenomenna that teh DES took advantage of to investigation dark matter distributions (ESA)

The data collected by the DES was cross-referenced against measurements carried out by the European Space Agency (ESA) operated mission, the Planck observatory. The orbiting observatory, which operated between 2009 and 2013 and studied the cosmic background radiation (CMB)–an imprint leftover from an event shortly after the Big Bang in which electrons and protons connected thus allowing photons to travel freely for the first time.

Observing the CMB reveals conditions that were ‘frozen in’ to it at the time of this event known as the last scattering and thus gives a detailed picture of the Universe when it was just 400 thousand years old for the DES team to draw from.

Setting the Scene for Future Surveys

The DES intensely studied ten regions labeled as ‘deep fields’ which were repeatedly imaged during the course of the survey. These images were stacked which allowed astronomers to observe distant galaxies.

In addition to allowing researchers to see further into the Universe and thus further back in time, information regarding redshift– an increase in wavelength caused by objects receding which can arise as a result of the Universe’s expansion–taken from these deep fields was used to calibrate the rest of the survey. This constituted a major step forward for cosmic surveys providing the researchers with a picture of the Universe painted with stunning precision.

Whilst the DES was concluded in 2019, the sheer wealth of data collected by the survey requires a huge amount of computing power and time to assess. This is why we are only seeing the first three years of observations reported and likely means that the DES still has much more to deliver.

The Vera C Rubin Observatory currently under construction in Chile will pick up where the DES leaves off (LSST Collaboration)

This will ultimately set the scene for the Legacy Survey of Space and Time (LSST) which will be conducted at the Vera C Rubin observatory–currently under construction on the El Penon peak of Cerro Pachon in northern Chile.

Whereas the DES surveyed an inarguably impressive 1/8 of the sky over the earth, the wide-field camera that will conduct the LSST will capture the entire sky over the Southern hemisphere, meaning it will view half of the entire sky over our planet.

A major part of the LSST’s mission will be the investigation of dark matter and dark energy, meaning that when the data from the DES is finally exhausted and its secrets are revealed, a worthy successor will be waiting in the wings to assume its mission of discovery.

Space and Physics Developments to Look Forward to in 2021

Unfortunately, science journalists don’t generally carry crystal balls as part of their arsenal, and if 2020 taught us anything, it’s not always safe to predict what the forthcoming year will bring. With that said, there are some space and physics developments that we can be fairly certain that will come to pass in 2021.

These are ZME Science’s tips for the top space science and physics events scheduled to occur in 2021.

Back to the Beginning with the James Webb Launch

It’s almost impossible to talk about the future of astronomy without mentioning NASA’s forthcoming James Webb Space Telescope (JWST). To call the launch of Webb ‘much-anticipated’ is a vast understanding.

The fully assembled James Webb Space Telescope with its sunshield and unitized pallet structures that will fold up around the telescope for launch (NASA)

The reason astronomers are getting so excited about the JWST is its ability to see further into the Universe, and thus further back in its history than any telescope ever yet devised. This will allow astronomers to observe the violent and tumultuous conditions in the infant Universe. Thus, it stands poised to vastly improve our knowledge of the cosmos and its evolution.

Part of the reason for JWST’s impressive observational power lies in its incredible sensitivity to infrared light–with longer wavelengths than light visible with the human eye.

The ability to observe the early Universe could help settle confusion about what point in its history galaxies began to form. Whilst the current consensus is that galaxies began to form in later epochs, a wealth of recent research has suggested that galaxies could have formed much earlier than previously believed.

“Galaxies, we think, begin building up in the first billion years after the big bang, and sort of reach adolescence at 1 to 2 billion years. We’re trying to investigate those early periods,” explains Daniel Eisenstein, a professor of astronomy at Harvard University and part of the JWST Advanced Deep Extragalactic Survey (JADES). “We must do this with an infrared-optimized telescope because the expansion of the universe causes light to increase in wavelength as it traverses the vast distance to reach us.”

An artist’s impression of the JWST in place after its 2021 launch (ESA)

The reason infrared is so important to observe the early Universe is that even though the stars are emitting light primarily in optical and ultraviolet wavelengths, travelling these incredible distances means light is shifted into the infrared.

“Only Webb can get to the depth and sensitivity that’s needed to study these early galaxies.”

Daniel Eisenstein, Havard University

After years of setbacks and delays and an estimated cost of $8.8 billion the JWST is set to launch from French Guiana, South America, on 31st October 2021.

JET Will Have Star Power

The race is on to achieve fusion power as a practical energy source here on Earth. Nuclear fusion is already the process that powers the stars, but scientists are looking to make it an energy source much closer to home.

Internal view of the JET tokamak superimposed with an image of a plasma ( EFDA-JET)

When it comes to bringing star power down to Earth the Joint European Torus (JET)–the world’s largest tokamak–leads the way, housing plasmas hotter than are found anywhere else in the solar system, barring the Sun.

A tokamak is a device that uses a powerful magnetic field to trap plasma, confining it in a doughnut-like shape. Containing and controlling these plasmas is the key to generating energy through the fusion process. Within the plasma, particles collide with enough energy to fuse together forming new elements and releasing energy.

The process is cleaner and more efficient than fission power, which rips the atoms of elements apart, liberating energy whilst leaving behind radioactive waste.

JET itself isn’t a power station, rather it was designed to conduct experiments with plasma containment and study fusion in conditions that approach that which will be found in working fusion power plants. So, whilst the International Thermonuclear Experimental Reactor (ITER)–set to be the world’s largest tokamak–is still under construction and won’t be operational until at least 2025, this year is set to be an important year for the experiment that inspired it.

Following upgrades conducted during 2020, JET is scheduled to begin experiments with a potent mix of the hydrogen isotopes deuterium and tritium (D-T). This fuel hasn’t been used since 1997 due to the difficulties presented by the handling of tritium– a rare and radioactive isotope of hydrogen with a nucleus of one proton and two neutrons.

The JET team will be looking to attain an output similar to the 16 megawatts of power that was achieved in ’97, but for a more sustained period and with less energy input. The initial test at the end of the 20th century consumed more power than it produced.

Back to the Moon in 2021

2021 will mark the 52nd anniversary of NASA’s historic moon landing and will see the launch of several missions back to Earth’s natural satellite as well as continuing efforts to send humans following in the footsteps of Armstrong and the crew of Apollo 11.

Illustration of Orion performing a trans-lunar injection burn (NASA)

As part of NASA’s deep space exploration system, Artemis I is the first in a series of increasingly complex missions designed to enable human exploration of the Moon and beyond.

“This is a mission that truly will do what hasn’t been done and learn what isn’t known. It will blaze a trail that people will follow on the next Orion flight, pushing the edges of the envelope to prepare for that mission.” 

Mike Sarafin, the Artemis I mission manager.

Artemis I will begin its journey aboard the Orion spacecraft, which at the time of its launch in November will be the most powerful spacecraft ever launched by humanity producing a staggering 8.8 million pounds of thrust during liftoff. After leaving Earth’s orbit with the aid of solar arrays and the Interim Cryogenic Propulsion Stage (ICPS) Orion will head out to the moon deploying a number of small satellites, known as CubeSats.

After a three week journey to and from the moon and six weeks in orbit around the satellite, Orion will return home in 2022, thus completing a total journey of approximately 1.3 million miles.

The Chandrayaan 2 launch. The ISRO will be hoping for better luck with Chandrayaan 3 in 2021 (ISRO)

NASA isn’t the only space agency with its sights set on the moon in 2021. The Indian Space Research Organisation (ISRO) will launch the Chandrayaan-3 lunar lander at some point in 2021. It will mark the third lunar exploration mission by ISRO following the Chandrayaan-2’s failure to make a soft landing on the lunar surface due to a communications snafu.

Chandrayaan-3 will be a repeat of this mission including a lander and rover module, but lacking an orbiter. Instead, it will rely on its predecessor’s orbiter which is still in good working despite its parent module’s unfortunate crash lander. Should Chandrayaan-3 succeed it will make India’s ISRO only the fourth space agency in history to pull off a soft-landing on the lunar surface.

(Robert Lea)

Back with a Blast: The LHC Fires Up Again

The world’s largest, most powerful particle accelerator, the Large Hadron Collider (LHC) ceased operations in 2018 and this year, after high-luminosity upgrades, it will begin to collide particles again.

During its first run of collisions from 2008 to 2013 physicists successfully uncovered the Higgs Boson, thus completing the standard model of particle physics. With the number of collisions increased significantly, in turn, increasing the chance of spotting new phenomenon, researchers will be looking for clues of physics beyond the standard model.

All quiet at the LHC in 2019, but the world’s largest particle accelerator will fire up again in 2021 (Robert Lea)

The function of the LHC is to accelerate particles and guide them with powerful magnets placed throughout a circular chamber that runs for 17 miles beneath the French-Swiss border. When these particles collide they produce showers of ‘daughter’ particles, some that can only exist at high energy levels.

These daughter particles decay extremely quickly–within fractions of a second– and thus spotting them presents a massive challenge for researchers.

Luminosity when used in terms of particle accelerators refers to the number of particles that the machine can accelerate and thus collide. More collisions mean more daughter particles created, and a better chance of spotting exotic and rare never before seen particles and phenomena. Thus, high luminosity means more particles and more collisions.

To put these upgrades in context, during 2017 the LHC produced around 3 million Higgs Boson particles. When the High-Luminosity LHC (HL-LHC) begins operations, researchers at cern estimate it will be producing around 15 million Higgs Bosons per year.

After being shut down for upgrades in 2018, the LHC prepares to fire up again in 2021 (CERN)

Unfortunately, despite firing up for a third run after these high luminosity upgrades, there is still work to be done before the LHC becomes the HL-LHC.

The shutdown that is drawing to completion–referred to by the CERN team as  Long Shutdown 2 (LS2)–was just part of the long operations that are required to boost the LHC’s luminosity. The project began in 2011 and isn’t expected to reach fruition until at least 2027.

That doesn’t mean that the third run of humankind’s most audacious science experiment won’t collect data that reveals stunning facts about the physics that governs that cosmos. And that collection process will begin in 2021.