Tag Archives: alien life

InSight maps Mars’ composition and chunky core for the first time

We are closer than ever before to understanding the composition of Mars thanks to the first observations of seismic activity on the planet made by the InSight lander. The NASA-led project, which landed on the surface of the Red Planet in November 2018 with the goal of probing beneath the Martian surface, observed several so-called ‘marsquakes’ which reveal details about its crust, mantle, and core.

Using seismic activity or ‘marsquakes’ researchers have detailed the composition of the Martian interior for the first time (Cottaar/ Science)

InSight’s primary findings which are detailed in three papers published today in the journal Science, represent the first time scientists have been able to produce a detailed picture of the interior of a planet other than Earth.

“We are seeking to understand the processes that govern planetary evolution and formation, to discover the factors that have led to Earth’s unique evolution,” says Amir Khan, ETH Zurich and the University of Zurich, whose team used direct and surface reflected seismic waves to reveal the structure of Mars’ mantle. “In this respect, the InSight mission fills a gap in the scientific exploration of the solar system by performing an in-situ investigation of a planet other than our own.”

The results from the ongoing NASA mission–with the full title ‘Interior Exploration using Seismic Investigations, Geodesy and Heat Transport’— could reveal key insights into the Red Planet‘s formation and evolution, as well as helping us understand the key differences between our planet and Mars.

“One big question we would like to understand is why Earth is the only planet with liquid oceans, plate tectonics, and abundant life?” adds Khan. “Mars is presently on the edge of the solar system’s habitable zone and may have been more hospitable in its early history. Whilst we don’t yet know the answers to these questions, we know they to be found are on Mars, most likely within its interior.”

The InSight Lander on the surface of Mars ((NASA/JPL-Caltech))

InSight first detected the presence of marsquakes from its position in Elysium Planitia near the Red Planet’s equator in 2019 and has since picked up more than 300 events–more than 2 a day–tracing many of them back to their source.

What is really impressive is what researchers can do with these quakes, using them as a diagnostic tool to ‘see’ deep into the planet’s interior.

“Studying the signals of marsquakes, we measured the thickness of the crust and the structure of the mantle, as well as the size of the Martian core,” Simon Stähler, a research seismologist at ETH Zurich, tells ZME Science. “This replicates what was done on Earth between 1900 and 1940 using the signals of earthquakes.”

From the Crust of Mars…

The observations made by InSight have allowed researchers to assess the structure of Mars’ crust, allowing them to determine its thickness and other properties in absolute numbers for the first time. The only values we previously had for the Martian crust were relative values that showed differences in thickness from area to area.

“As part of the bigger picture on the interior structure of Mars, we have determined the thickness and structure of the Martian crust,” Brigitte Knapmeyer-Endrun, a geophysicist at the University of Cologne’s Institute of Geology, tells ZME Science. “Previous estimates could only rely on orbital data–gravity and topography–that can accurately describe relative variations in crustal thickness, but no absolute values. These estimates also showed a wide variability.”

The Mars InSight lander’s seismometer consists of a protective dome that contains three extremely sensitive sensors. (NASA/JPL-Caltech)

With data collected regarding the crustal thickness at InSight’s landing area, new seismic measurements, and data collected by previous missions, the team could map the thickness across the entire Martian crust finding an average thickness of between 24 and 72 km.

Knapmeyer-Endrun explains that the data she and her team collected with InSight’s Seismic Experiment for Interior Structure (SEIS), particularly the very broad-band (VBB) seismometer–an instrument so sensitive it can record motion on an atomic scale–and information from the Marsquake Service (MQS) at ETH Zurich, suggest that the Red Planet’s crust is thinner than models have thus far predicted.

“We end up with two possible crustal thicknesses at the landing site–between 39 and 20 km– but both mean that the crust is thinner than some previous estimates and also less dense than what was postulated based on orbital measurements of the surface.”

Knapmeyer-Endrun continues by explaining that the InSight data also reveals the structure of the Martian crust as multi-layered with at least two interfaces that mark a change in composition. In addition to this, the team can’t rule out the presence of a third crustal layer before the mantle.

“The crust shows distinct layering, with a surficial layer of about 10 km thickness that has rather low velocities, implying that it probably consists of rather porous–fractured–rocks, which is not unexpected due to the repeated meteorite impacts,” says the geophysicist adding that we see something similar on the Moon, but the effect is more extreme due to that smaller body’s much thinner atmosphere.

The two largest quakes detected by NASA’s InSight appear to have originated in a region of Mars called Cerberus Fossae. Scientists previously spotted signs of tectonic activity here, including landslides. This image was taken by the HiRISE camera on NASA’s Mars Reconnaissance Orbiter (NASA/JPL-Caltech/University of Arizona)

Knapmeyer-Endrun is pleasantly surprised regarding just how much information InSight has been able to gather with just one seismometer.”It’s surprising we were really able to pull all of this information about the interior of Mars from the recordings of quakes with magnitudes of less than 4.0 from a single seismometer,” she explains. “On Earth, we would not be able to even detect those quakes at a comparable distance. We typically use 10s or even 100s of seismometers for similar studies.”

And the marsquake data collected by InSight has not just proven instrumental in assessing the thickness and composition of the planet’s crust, it has also allowed scientists to probe deeper, to the very core of Mars itself.

…To the Martian Mantle and Core

Using direct and surface reflected seismic waves from eight low-frequency marsquakes Khan and his team probed deeper beneath the surface of Mars to investigate the planet’s mantle. They found the possible presence of a thick lithosphere 500km beneath the Martian surface with an underlying low-velocity layer, similar to that found within Earth. Khan and his co-author’s study reveals that the crustal layer of Mars is likely to be enriched with radioactive elements. These elements heat this region with this warming reducing heat in lower layers.

It was these lower regions that Stähler and his colleagues investigated with the use of faint seismic signals reflected by the boundary between the Martian mantle and the planet’s core. What the team discovered is that the Red Planet’s core is actually larger than previously calculated, with a radius of around 1840 km rather than previous estimates of 1600km. This means the core begins roughly halfway between the planet’s surface and its centre.

From the new information, we can also determine the core’s density and extrapolate its composition.

A Comparison of Mars’ Earth’s interiors. The Martian core shown here is smaller than these new findings suggest. Whilst the crust shown is thicker.



“We now know for sure the size of the core and it’s significantly larger than it had been thought to be for a long time,” says Stähler. “Because we found that the core is quite large, we, therefore, know it is not very dense. This means that Mars must have accumulated a substantial quantity of light, volatile elements such as sulfur, carbon, oxygen, and hydrogen.”

This ratio of lighter elements is greater than that found within Earth’s denser core, and it could give us important hints about the differences in the formation of these neighbouring worlds.

“Somehow these light elements needed to get into the core. It may mean that the formation of Mars happened faster than Earth’s,” Stähler says. “These observations have fueled speculation that Mars might represent a stranded planetary embryo that depicts the chemical characteristics of the solar nebula located within the orbit of Mars.”

Thanks to NASA's InSight Mars mission we now have a good picture of the interior of another planet.
InSight captures an image of its landing site, which proved the ideal vantage point to observe marsquakes (NASA)

As just Knapmeyer-Endrun did, Stähler expresses some surprise regarding just how successful InSight has been in gathering seismological data, emphasising the role good fortune has played in the mission thus far.

“We were able to observe reflections of seismic waves from the core–like an echo–from relatively small quakes. And the quakes were just in the right distance from the lander. Had we landed in another location, it would not have worked out,” the seismologist says. “And the landing site was only selected because it was flat and had no rocks, so it was really pure luck.”

Stähler says that he and his team will now attempt to use seismic waves that have crossed the core of Mars to determine if the planet’s core possesses a solid-iron inner-core like Earth, or if it is entirely liquid. Just one of the lingering questions that Knapmeyer-Endrun says InSight will use marsquakes to tackle over the coming years.

“There are still multiple open questions that we’d like to tackle with seismology. For example, which geologic/tectonic features are the observed marsquakes linked to? At which depth do olivine phase transitions occur in the mantle? And Is there a solid inner core, like on Earth, or is the whole core of Mars liquid?” says the geophysicist.

And if we are to go by track record, the smart money is on InSight answering these questions and more. “Within just 2 years of recording data on Mars, this single seismometer has been able to tell us things about the crust, mantle and core of Mars that we’ve been speculating about for decades.”

What is the Drake Equation: the math that predicts how many alien civilizations are out there

Are we alone in the universe? This is one of the biggest questions science is trying to answer. Many are inclined to think that there is indeed life beyond Earth. After all, there are billions of galaxies each with billions of stars. Surely, among them, there must be other Earth-like planets and sun-like stars capable of seeding life.

But however groundbreaking finding microbes on another planet would be, that would pale in significance to making contact with another alien civilization.

There’s actually a way to estimate how many alien civilizations may reside in the Milky Way thanks to a statistical model developed in the 1960s known as the Drake equation, named after astronomer Dr. Frank Drake.

What is the Drake Equation

The Drake equation, a mathematical formula for the probability of finding life or advanced civilizations in the universe. Credit: University of Rochester.

The Drake equation is a probabilistic method for estimating the number of advanced extraterrestrial civilizations (N) that harbor technology capable of communicating their existence.

The Drake equation itself is:

N = R* x fp x ne x fl x fi x fc x L

Where:

  • R* represents the average rate of star formation in our galaxy
  • fp is the fraction of stars that have planets
  • ne is the fraction of planets that orbit their parent stars in the habitable zone, also known as the Goldielocks zone, i.e. can potentially support liquid water at the surface and life
  • fl  is the fraction of planets that could support life and actually do develop life at some point
  • fi is the fraction of planets that harbor life that evolves into an intelligent species capable of founding civilizations
  • fc is the fraction of civilizations that develop technology that emits detectable signals of their existence into space (i.e. artificial radio signals)
  • L is the length of time for which extraterrestrial civilizations release detectable signals into space (before they may go extinct, for instance)

The story of how the Drake equation can be traced back to the early 1950s when radio astronomy — the study of celestial objects’ radio frequencies — became more widespread. If they could detect radio signals from pulsars and far-away galaxies, they should also be able to detect artificial extraterrestrial signals, scientists thought at the time.

Frank Drake posing beside his famous equation. Credit: SETI.org.

First, scientists listened to artificial radio signals from Mars. Then, in the late 1950s, physicists Giuseppe Cocconi and Philip Morrison argued in a milestone paper that radio telescopes had become sensitive enough that they could detect radio transmissions from other star systems. The pair of scientists further argued that some of these messages would likely be transmitted at a frequency of 1420.4 Mhz, which corresponds to the wavelength of neutral hydrogen. Since hydrogen is the most abundant element in the universe, it would only be logical for an advanced civilization to broadcast its existence at this frequency to other star systems.

Dr. Frank Drake, a young astronomer at the time, had independently reached the same conclusion as Cocconi and Morrison. In spring 1960, Drake embarked on the first microwave radio search for signals from another solar system, aiming the 85-foot antenna of the National Radio Astronomy Observatory in Green Bank, West Virginia, tuned to 1,420 Mhz, in the direction of two nearby Sun-like stars.

Shortly after, at a meeting at the Green Bank facility in 1961, Drake had a speech in which he revealed for the first time his famous equation as a way to stimulate scientific discussion and interest around the search for intelligent alien life.

“As I planned the meeting, I realized a few day[s] ahead of time we needed an agenda. And so I wrote down all the things you needed to know to predict how hard it’s going to be to detect extraterrestrial life. And looking at them it became pretty evident that if you multiplied all these together, you got a number, N, which is the number of detectable civilizations in our galaxy. This was aimed at the radio search, and not to search for primordial or primitive life forms,” Drake said.

These pioneering efforts sparked the Search for Extra-Terrestrial Intelligence (SETI) movement spearheaded by Soviet and American scientists. By the late 1980s, large-scale SETI projects were established that examined thousands of sun-like stars at a time, culminating with NASA’s Project Phoenix —  the world’s most sensitive and comprehensive search for extraterrestrial intelligence. Project Phoenix eventually moved to the now-defunct Arecibo observatory, which collapsed last year in Puerto Rico, and scanned nearly 800 stars, all within 200 light-years distance, at frequencies between 1,200 and 3,000 MHz. 

Although SETI scientists came back empty-handed and interest (along with public funding) waned, the search for intelligent life continues. The privately-funded SETI Institute is currently building a dedicated array of telescopes that will equal a 100-meter radio telescope, known as the Allen Telescope Array (ATA). This will be the first radio telescope designed from the ground up for the sole purpose of performing SETI searches. The first 42 elements have already been installed at the Hat Creek Observatory, situated in the Cascade Mountains about 300 miles north of San Francisco.

So how many advanced alien civilizations are out there?

The Drake equation isn’t exactly rooted in hard science and is more of a speculative framework. Over the years, the equation took a lot of flak from the scientific community due to the many assumptions it makes. For instance, the first exoplanet was only discovered in 1992, more than 30 years after Drake proposed his equation.

Although we can estimate some factors of the equation with relatively high confidence — we know for instance that there are about two trillion galaxies in the known universe and that the Milky Way is home to 200 to 400 billion stars — other variables are far more uncertain. In particular, the odds of an exoplanet in the habitable zone actually hosting life is perhaps the most difficult to gauge since we know of only one planet so far capable of doing so, Earth.

Drake’s equation was made famous by the late Carl Sagan, who featured it during an episode of his timeless series Cosmos. But since Sagan first talked about Drake’s equation, much has changed. Thanks to observations by the Kepler telescope, we now have a much firmer grasp of how many Earth-like worlds may be out there.

Crunching the Drake equation with various values, the number N of advanced civilizations in the Milky Way ranges from as low as 0.000000000091 (we are probably very much alone in the Milky Way) to as high as 15,600,000 (the Milky Way is home to millions of distinct intelligent civilizations).

In a 2016 study published in the journal Astrobiology, Adam Frank, professor of physics and astronomy at the University of Rochester, and  Woodruff Sullivan, an astrobiologist at the University of Washington, looked at this question from another angle.

Rather than asking how many civilizations may exist in the Milky Way — the main premise of the Drake equation — the two scientists calculated the odds that humans represent the only technological species that has ever arisen. Flipping the question means that rather than guessing at the odds of advanced life developing, the two calculated the odds against it occurring in order for humanity to be the only advanced civilization in the entire history of the observable universe.

“This shifted focus eliminates the uncertainty of the civilization lifetime question and allows us to address what we call the ‘cosmic archaeological question’—how often in the history of the universe has life evolved to an advanced state?” said Sullivan.

By applying the most recent data on exoplanets at the time, Sullivan and Frank found that the odds that human civilization is unique in the cosmos (2×1022 stars) is about one in 10 billion trillion, or one part in 1022.

“One in 10 billion trillion is incredibly small,” says Frank. “To me, this implies that other intelligent, technology producing species very likely have evolved before us. Think of it this way. Before our result you’d be considered a pessimist if you imagined the probability of evolving a civilization on a habitable planet were, say, one in a trillion. But even that guess, one chance in a trillion, implies that what has happened here on Earth with humanity has in fact happened about a 10 billion other times over cosmic history!”

The Drake equation and Fermi’s Paradox

But if that were true, where are all the aliens? This is the question that physicist Enrico Fermi, the inventor of the world’s first nuclear reactor, asked as well when he posited his famous Fermi Paradox — the notion of how there are a virtually limitless number of stars, but you don’t see much life floating around.

The question is a valid one when considering:

  • There’s nothing special about our sun – it’s young, medium-sized and similar to billions of other stars in our galaxy.
  • It’s believed there are between 100 and 400 billion planets in the Milky Way. Considering intelligent life appeared on one, it’s reasonable to consider there should be at least some other kind of intelligent life elsewhere in the galaxy.
  • Millions of years of technological progress mean that an intelligent species should have the capability to travel to distant stars and even other galaxies. Just look at how our world has changed in the past 100 years alone.
  • According to mathematicians Duncan Forgan and Arwen Nicholson from Edinburgh University, self-replicating spacecraft traveling at one-tenth of the speed of light — admittedly a quick speed — could traverse the entire Milky Way in a mere 10 million years. This means that civilization could potentially colonize the whole galaxy in a mere couple of millions of years. Except it didn’t happen.

The most straightforward explanation for this paradox is that the vast majority of these advanced alien civilizations, if not all, went extinct. Perhaps we too will go extinct as fast as we came into this world.

“The universe is more than 13 billion years old,” said Sullivan. “That means that even if there have been a thousand civilizations in our own galaxy, if they live only as long as we have been around—roughly ten thousand years—then all of them are likely already extinct. And others won’t evolve until we are long gone. For us to have much chance of success in finding another “contemporary” active technological civilization, on average they must last much longer than our present lifetime.”

“Given the vast distances between stars and the fixed speed of light we might never really be able to have a conversation with another civilization anyway,” said Frank. “If they were 20,000 light years away then every exchange would take 40,000 years to go back and forth.”

The inevitability of self-annihilation of intelligent life is an opinion shared by scientists at NASA’s Jet Propulsion Laboratory and Caltech who also made their own spin on Drake’s equation in a 2020 study.

The researchers found that life was most likely to emerge around 13,000 light-years from the galactic centers, where there is the greatest density of sun-like stars. The optimal time frame for the development of alien civilizations was estimated at 8 billion years after the formation of the galaxy. For comparison, Earth is about 25,000 light-years from the galactic core and complex intelligent life evolved around 13.5 billion years after the Milky Way formed.

According to the researchers, most civilizations that have appeared before us have likely self-annihilated. Other civilizations that are still active in the galaxy are likely young, due to the propensity of intelligent life to eradicate itself. Over a long enough timeframe, the probability of self-annihilation borders on certainty.

“As we cannot assume a low probability of annihilation, it is possible that intelligent life elsewhere in the Galaxy is still too young to be observed by us. Therefore, our findings can imply that intelligent life may be common in the Galaxy but is still young, supporting the optimistic aspect for the practice of SETI (search for extraterrestrial intelligence),” the authors wrote in their study.

“Our results also suggest that our location on Earth is not within the region where most intelligent life is settled, and SETI practices need to be closer to the inner Galaxy, preferably at the annulus 4 kpc (kiloparsec) from the Galactic Center.”

Other possible explanations for the apparent silence in the universe include the possibility that life is exceedingly rare (let alone the intelligent variety) or that humanity is simply too early to the party. We may be alone but only for the time being.

Elon Musk’s Starlink satellites are triggering a “UFO” craze

Around the world, social media users are reporting seeing a mysterious row of bright lights gliding across the sky — which many claim to be UFOs. Exciting as it may sound, it’s likely something far less exciting: a chain of Starlink satellites developed by Elon Musk’ SpaceX. 

Image credit: Richard Houle

Last week, Starlink launched its latest wave of 52 satellites from Kennedy Space Center in Florida. It has already launched more than 600 of its 12,000 planned satellites, usually set off in batches of 60. They are usually described as “megaconstellations” because they are a group of satellites moving together.

Paul Lynam, a resident astronomer at Lick Observatory on Mount Hamilton, told The San Francisco Chronicle said the satellites were “catching and reflecting sunlight either in the couple hours after sunset or before sunrise” — which is what a growing number of people are reporting seeing. The sightings are becoming more common as SpaceX continues to populate its constellation space,” he added.

Over the last few years, more people seem to have been seeing these strange lights. In Canada, for example, there has been a notable surge in the number of calls to 911 dispatchers, with people calling to report UFO sightings near their homes. 

“We were getting a lot of calls with the SpaceX satellite launches. They’re a very specific pattern in the sky, they’re not hitting the ground, and we can just explain very quickly to people that there are actual satellites,” Tracy Duval, a dispatcher, told CityNews. We have situations where people are saying that the aliens are coming.”

While seeing these satellites in the sky can be an exciting experience and fuel the imagination (sparking images of aliens and UFOs), astronomers around the world are very concerned about the megaconstellations of SpaceX satellites. They worry that these satellites will be too bright and will interfere with visibility for scientific observations. But for people around the world, the satellites can be a godsend.

Under Starlink, SpaceX is developing a satellite network to provide global broadband coverage for high-speed internet access, particularly for people across the world in rural and remote areas. The service is now being beta tested by a limited number of users. It’s reportedly 47% faster than fiber-optic cable internet, the company has said.

The US Federal Communications Commission (FCC) has granted SpaceX permission to fly 12,000 satellites, and perhaps as many as 30,000 eventually. This is massive. There are now only 2,000 active satellites orbiting the Earth that are key to modern life, from mobile phones to internet. Less than 9,000 have ever been launched in all of history.

The Starlink satellites orbit at an altitude of 550 kilometers, which is low enough to get pulled down to Earth by atmospheric drag and burn up in a few years. This means they won’t become space junk once they die, which was an initial concern. Each weighs about 227 kilograms and measures about the size of a typical coffee table. 

Musk and his company have been questioned by the astronomical community due to their brightness and potential to disrupt observations of the night sky. This is because the satellites are brighter than most of the stars visible to the human eye and also move faster through the sky. This leaves a trail that can pollute astronomer’s data.

In response, SpaceX started equipping its satellites with a blackened sunshade called VisorSat. The company says it will lower the satellite’s apparent brightness by reducing the amount of sunlight that’s reflected. Initial efforts included launching a satellite with a black antireflecting coating, which was half as bright as a standard satellite. 

If noticing a UFO was difficult, the satellites are making it more difficult. Still, don’t lose hope. There might still be a green guy out there waiting for us yet. 

A Snapshot of Gliese 486b's journey around its parent star (Render Area)

Nearby Super-Earth could be perfect for atmospheric investigation

An international team of astronomers has discovered a nearby exoplanet orbiting a red dwarf star that is perfect for deeper investigation. In particular, this exoplanet could be a prime target for precise atmospheric measurements, something that, for planets outside the solar system, has so-far eluded astronomers.

The team’s findings documenting the discovery of this relatively close super-Earth–so-called because they have a mass greater than our planet but still lower than planets like Uranus and Neptune which are classified as ‘ice giants’–are published in the latest edition of the journal Science.

The team discovered Gliese 486 b whilst surveying 350 small red dwarf stars for signs of low-mass planets using the CARMENES spectrograph mounted on the 3.5m telescope at the Calar Alto Observatory telescope, Spain. The exoplanet was found due to the ‘wobble’ it caused in the orbit of its parent star.

A snapshot of the super-Earth Gliese 486 b as it orbits a red dwarf star (Render Image)

“Our team is searching primarily for Earth-like and super-Earth planets orbiting nearby stars. In this case, we have found a nearby super-Earth, just 26 light-years away orbiting a small star every 1.5 or so Earth days,” Karen Collins, an astronomer at the Center for Astrophysics, Harvard & Smithsonian, and a co-author on the paper tells ZME Science. “We were certainly excited to have found a transit signal in the light curve of a star that is so close to the Sun in astronomical terms.

“We quickly realized that Gliese 486 b, with radial velocity mass measurements in hand, would likely become a prime target for additional detailed follow-up studies, particularly atmospheric investigations.”

Karen Collins, Center for Astrophysics, Harvard & Smithsonian

These investigations could include searching for the conditions necessary for life, or even for biomarkers left behind by simple lifeforms.

The astronomers were able to spot Gliese 486 b thanks to the ‘wobble’ it caused in its parent star’s orbit (Render Area)

Colins continues by explaining that it is Gliese 486 b’s proximity–it is the third closest transiting exoplanet yet to be uncovered– that, amongst other things like its temperature, makes it a good candidate for more in-depth study. “Because Gliese 486 b is so close to the solar system, relative to most known transiting exoplanets, we may be able to probe the atmosphere of the planet using the upcoming James Webb Space Telescope and possibly other telescopes,” she explains.

That is, of course, if it actually has an atmosphere.

What We Know About Gliese 486 b So Far…

Whilst the team of astronomers may not yet be certain that Gliese 486 b has an atmosphere, there are some things that they do know about the exoplanet and its red dwarf home star.

Artistic impression of the surface of the newly discovered hot super-Earth Gliese 486b. With a
temperature of about 700 Kelvin (430 °C), Gliese 486b possibly has an atmosphere (Render Area)

“It is only about 30% larger than Earth but has a mass of about 2.8 times that of our planet,” study author Trifon Trifonov, Max Planck Institute for Astronomy, explains to ZME Science. The researcher adds that models suggest that the exoplanet’s composition is similar to Venus and Earth, including a metallic core. “Anyone standing on Gliese 486 b would feel a gravitational pull that is about 70% stronger than what we experience on Earth.”

In addition to being denser than the earth, Gliese 486 b is also much hotter according to Trifon. This is because the exoplanet revolves around its host star on a circular orbit every 1.47 days, with one side permanently pointing towards its parent star.

“The proximity to the red dwarf Gliese 486 heats the planet significantly, making its landscape hot and dry, interspersed with volcanos and glowing lava rivers,” Trifon says. “There are quite a few super-Earth type exoplanets already discovered. All of these exoplanets are exceptional on their own. In this context, the physical characteristics of Gliese 486 b are not uncommon. However, the proximity of Gliese 486 b, allowed us to measure its mass with unprecedented precision, thanks to observations done with the CARMENES and the MAROON-X instruments.”

From the information the astronomers do possess regarding Gliese 486 b, especially its mass, Collins adds that the clues it also has an appreciable atmosphere are in place.

“Because we do know that the planet surface gravity is relatively high–about 70% stronger than Earth–we believe that there is a chance the planet may have retained an appreciable atmosphere.”

Karen Collins, Center for Astrophysics, Harvard & Smithsonian

Atmospheric Investigations

Using NASA’s Transiting Exoplanet Survey Satellite (TESS) spacecraft the astronomers were able to deduce that Gliese 486 b periodically crosses the stellar disk of its parent red dwarf star, a rare and fortuitous event.

“For transiting planets like Gliese 486 b, we have two primary methods to probe the atmospheres, if they exist,” Collins continues. “Transit spectroscopy allows us to study the planet’s atmosphere as the planet passes in front of the star from the telescope’s perspective.”

Collins says that should the exoplanet possess an atmosphere part of the light from its parent star that reaches our telescopes will have been filtered through this. This means that the light profile filtered by the atmosphere can be compared to an unfiltered version when the planet is not in front of the star.”By comparing the in-transit spectrum of the star with a spectrum of the star when the planet is not transiting, we can isolate atmospheric signals from the planet and possibly detect some of the components of the atmosphere.”

As Gliese 486 b transits the face of its parent star, astronomers should be able to use transit spectroscopy to investigate its atmosphere. (Render Area)

The second method detailed by Collins involves the detection of radiation directly from an exoplanet’s hot surface as it occupies different orbital phases across the star’s face. The emission spectrum that gives this technique its name–emission spectroscopy–reveals characteristic traits that indicate the presence of certain elements emitting and absorbing light in the exoplanet’s atmosphere.

“Its temperature of around 700 Kelvin makes it suitable for emission spectroscopy and phase curve studies in search of an atmosphere,” adds Trifonov.

The Golden Age of Exoplanet Science

Concluding our interview I ask Collins and Trionov if we are entering a ‘Golden Age’ for exoplanet science. They are both quick to correct me. “I would say we are living in it!” Trinov exclaims. “During the past three decades, astronomers have discovered thousands of exoplanets, and the number is increasing daily.

“Every day, we enhance our knowledge about the physical properties of exoplanets, their formation, and evolution.”

Trifon Trifonov, Max Planck Institute for Astronomy
NASA engineers are putting the finishing touches to the James Webb Space Telescope. The instrument will play a crucial role is the future investigation of super-Earth exoplanets. (NASA)

Collins is equally assured that exoplanet science is in its prime, but adds that there is no decline in sight. “Frankly, I believe we have been in the golden age of exoplanet science for over a decade now,” the astronomer says. “Even so, with the advent of TESS to discover and measure the size of nearby small transiting planets, precise radial velocity machines like that of the CARMENES consortium and the MAROON-X instrument to measure their masses, and soon the James Webb Space Telescope to investigate their atmospheres, it’s fair to say that we are entering the golden age of well-characterized small planet exoplanet science.”

And Collins is clear how lucky she regards herself for just being involved with astronomy at this crucial juncture in its history. “I am excited to be involved in the search for and characterization of Earth-sized and Super-Earth planets such as Gliese 486 b,” says explains enthusiastically. “Precise atmospheric measurements are likely around the corner! What will this relatively new scientist from a small but progressive astrophysics program at a school in Kentucky be involved with next? Will we soon discover an Earth twin with an Earth-like atmosphere or even signs of life in an atmosphere?

“It is almost as if I’m living in a series of Star Trek. I can’t wait to see what we discover next!”

Karen Collins, Center for Astrophysics, Harvard & Smithsonian

Game theory could be the key for finding intelligent alien life

Dr. Eamonn Kerins, an astrophysicist from the University of Manchester, has an idea for the Search for Extraterrestrial Intelligence (SETI). It consists of a strategy called Mutual Detectability based on coordination game, a strategy in which both players make the same decision.

The Very Large Array (VLA) 27 radio antennas, New Mexico. Credit: Alex Savello/NRAO.

Imagine you’re at a concert and your phone battery is dead, but you need to find a friend. How do you do it?

Here’s an approach: both of can you employ the same strategy and find each other in the middle of the crowd. In this situation, both parties win a payoff for having the same desire and the same decisions. This is what Mutual Detectability is about. If two civilizations have enough knowledge of each other, it is likely they will try to communicate and reach each other. This type of strategy rationalization is the basis of game theory, and Kerins believes applying game theory to SETI could be a fruitful strategy.

Opposites don’t always atract

One obstacle for the civilizations looking for other civilizations has to do with technological advancement. When one civilization is more powerful than the other, the less powerful will feel less comfortable in making contact — for obvious reasons. Any civilization looking for others would have an incentive to listen, but not send out signals, so our galaxy might be full of listeners not able to find each other.

However, even if two civilizations are trying to find each other, they might not be able to if they use very different technologies. This could be avoided, says Kerins, if the more advanced civilization would use less-advanced signals. But you’d still need to actually be able to find them. This leads to the SETI paradox, if intelligent beings are looking for intelligent beings but not trying to reach out, then SETI is in vain.

Where to look?

Kerins points to the importance of the region of the Earth Transit Zone(ETZ). The idea is simple: not all planets in the universe can see us. If an alien civilization can observe us when our planet passes in front of the Sun and reduces its luminosity, they will be able to detect us. This is called the transit method, used by astronomers to detect exoplanets.

ETZ is the optimal area in which other beings could detect us in the galaxy using the transit method. Success in mutual detectability could mean detecting planets in the habitable zone and that are in the ETZ region. Similarly, we should focus on detecting potentially habitable planets that could be able to see us.

The transit method. Credit: NASA Ames.

Good news is, there’s at least one planet that fits the bill.

K2-155 d is a Super-Earth in the habitable zone that happens to be in ETZ. The planet orbits an M dwarf star, the smallest type of star we know of, but it orbits it close enough to potentially have habitable temperatures. This type of star also makes the transit method easier to succeed, because a relatively small star has a clearer response to the transit. In other words, we see it blinking more clearly. That would be one starting to point SETI telescopes at.

But we already know many exoplanets. Only the Kepler mission discovered 2,662 planets in nearly 10 years of service. If we continue the search for planets and match the criteria stated by Dr. Kerins, our chances of communication would increase and the loneliness of Earth could end.

The theory was published in The Astronomical Journal.

The melting of ice beneath the surface of Mars could have made its deep regions the most habitable.

Life could have prospered beneath the surface of Mars

Even after liquid water was stripped from its surface, new research suggests that freshwater miles beneath the surface could have sustained life. (Steve Lee, Univ. Colorado/Jim Bell, Cornell Univ./Mike Wolff, SSI/NASA)

Life-sustaining water could have existed miles beneath the surface of Mars thanks to the melting of thick ice sheets by geothermal heat, new research has found. The discovery, made by a team led by Rutgers University scientists, suggests that 4 billion years ago the most likely place for life to prosper on the Red Planet was beneath its surface.

The study, published in the latest edition of the journal Science Advances, could solve a problem that also has implications for the existence of liquid water–and thus the early development of life–on our planet too. Thus far, researchers looking into the existence of liquid water early in both Earth and Mars’histories have been puzzled by the fact that the Sun would have been up to 70% less intense in its stellar-youth.

A vertically exaggerated and false-colour perspective of a large, water-carved channel on Mars called Dao Vallis. Whether channels like these on Mars were carved by surface water or groundwater is highly debated. The channel is ~40 km wide, ~2.5 km deep, and more than 500 km in length. (ESA/DLR/FU Berlin, CC BY-SA 3.0 IGO. 3D rendered and coloured by Lujendra Ojha.)
A vertically exaggerated and false-colour perspective of a large, water-carved channel on Mars called Dao Vallis. Whether channels like these on Mars were carved by surface water or groundwater is highly debated. The channel is ~40 km wide, ~2.5 km deep, and more than 500 km in length. (ESA/DLR/FU Berlin, CC BY-SA 3.0 IGO. 3D rendered and coloured by Lujendra Ojha.)

This lack of intensity coupled with findings of liquid water at this stage in the solar system’s history is referred to as ‘the faint-sun paradox,’ and should mean that Mars conditions were cold and arid in its deep history. This conclusion was contradicted by geological evidence of liquid water on the young planet. The problem could now be solved, for Mars at least, by geothermal activity.

“Even if greenhouse gases like carbon dioxide and water vapour are pumped into the early Martian atmosphere in computer simulations, climate models still struggle to support a long-term warm and wet Mars,” explains lead author Lujendra Ojha, assistant professor in the Department of Earth and Planetary Sciences in the School of Arts and Sciences at Rutgers University, New Brunswick. “We propose that the faint young sun paradox may be reconciled, at least partly, if Mars had high geothermal heat in its past.”

Lujendra Ojha, Jacob Buffo, Suniti Karunatillake, Matthew Siegler. [2020]
Lujendra Ojha, Jacob Buffo, Suniti Karunatillake, Matthew Siegler. [2020]

The status of Mars climate billions of years ago and if freshwater could have existed its this point early in its history has been a source of heated debate in the scientific community for decades. The discussion has been further complicated by the question of whether water would have existed on the planet’s surface or deep underground? Climate models produced for Mars thus far have suggested average surface temperatures below the melting point of water at this point in its history.

Ojha and his team investigated this seeming contradiction in our understanding of Mars by modelling the average thickness of ice deposits in the Red Planet’s southern highlands. They also examined data collected by NASA’s InSight lander, which has been measuring the ‘vitals’ of the Red Planet since 2018.

Discovering that the thickness of these ice deposits did not exceed an average thickness of 2 kilometres, the team complemented this finding with estimates of both the planet’s average annual surface temperature and the flow of heat from its interior to its surface. The aim of this was to discover if the surface heat flow would have been strong enough to melt Mars’ ice sheets.

Indeed, the study seems to show that the flow of heat from both the crust and mantle of Mars would have been intense enough to begin melting at the base of its ice sheets.

Did Life on Mars prosper Beneath its Surface?

Water still exists on Mars in the forma of Ice as seen in the Korolev crater. (ESA)
Water still exists on Mars in the forma of Ice as seen in the Korolev crater. (ESA)

The wider implication of this revelation is that whatever the climate of Mars was like billions of years in its history if life once existed on the Red Planet, its subsurface would have been its most habitable region. Thus, life could have prospered, say the team, miles beneath the surface of our neighbour, sustained by the flow of freshwater.

Significantly, this supply of water would have existed even as Mars lost its magnetic field and its atmosphere was stripped away by harsh solar winds and blistering radiation. The process which ultimately deprived Mars of its surface liquid water. This means that life could have survived on the planet, hidden miles underground for much longer than the surface remained habitable.

“At such depths, life could have been sustained by hydrothermal activity and rock-water reactions,” says Ojha. “So, the subsurface may represent the longest-lived habitable environment on Mars.”

Source: Lujendra Ojha, Jacob Buffo, Suniti Karunatillake, Matthew Siegle. ‘Groundwater production from geothermal heating on early Mars and implication for early martian habitability,’ Science Advances,[2020] https://advances.sciencemag.org/lookup/doi/10.1126/sciadv.abb1669

An artist's conception of HD 209458 b, an exoplanet whose atmosphere is being torn off at more than 35,000 km/hour by the radiation of its close-by parent star. This hot Jupiter was the first alien world discovered via the transit method, and the first planet to have its atmosphere studied. [NASA/European Space Agency/Alfred Vidal-Madjar (Institut d'Astrophysique de Paris, CNRS)]

Stellar flares can strip away the atmosphere of planets, make them less habitable

As humanity continues to explore planets beyond the solar system — exoplanets — investigations into conditions on these worlds become increasingly complex. This includes the question of whether these exoplanets can support life. 

New research has identified which stars would be most likely to host planets with the necessary conditions for habitability, based upon that star’s stellar activity and crucially the rate at which such activity strips away a planet’s atmosphere. 

“We wanted to figure out how planets lose their atmospheres from extreme ultraviolet radiation and estimate their impact on their potential to host life,” Dimitra Atri, a researcher from the Space Science at NYU Abu Dhabi (NYUAD), tells ZME Science. “We focused on a channel of escape called hydrodynamic escape where stellar radiation heats up the planet’s atmosphere and a part of it escapes into space.”

An artist's conception of HD 209458 b, an exoplanet whose atmosphere is being torn off at more than 35,000 km/hour by the radiation of its close-by parent star. This hot Jupiter was the first alien world discovered via the transit method, and the first planet to have its atmosphere studied. [NASA/European Space Agency/Alfred Vidal-Madjar (Institut d'Astrophysique de Paris, CNRS)]
An artist’s conception of HD 209458 b, an exoplanet whose atmosphere is being torn off at more than 35,000 km/hour by the radiation of its close-by parent star. This hot Jupiter was the first alien world discovered via the transit method, and the first planet to have its atmosphere studied. [NASA/European Space Agency/Alfred Vidal-Madjar (Institut d’Astrophysique de Paris, CNRS)]

Atri is the author of a paper published in the journal Monthly Notices of Royal Astronomical Society: Letters, which analyzes flare emissions using data collected by NASA’s Transiting Exoplanet Survey Satellite (TESS) observatory ultimately helping to determine where else in the Universe life is most likely to prosper.

Harbouring Life: A Question of Water Retention

Planet habitability is closely associated with that world’s ability to hold liquid water. That means that factors which can boil away that water or cause it to be lost to space reduce that habitability. The habitable zone of a star’s environment is defined as the range at which a planet can orbit and still possess liquid water. This means not too hot or too cold — criteria that led to the alternative name for such regions, the Goldilocks zone.

Yet, distance and a star’s luminosity are not the only factors which can affect a planet’s ability to hold liquid water. Space weather — including solar flares — is another determining element, one that as of yet is not well understood. “Flares erode planetary atmospheres,” Atri says. “A substantial atmosphere is needed to sustain liquid water on a planet’s surface. Flares reduce those chances and make planets less habitable.”

Betelgeuse a type H 1-2 star similar to those Atri found jettison frequent XUV flares which can strip an exoplanet’s atmosphere reducing conditions for habitability (NASA/SDO)

What Atri, alongside coauthor and graduate student Shane Carberry Mogan, discovered was that whilst luminosity from a star was still the primary driving factor in atmosphere stripping, flares were a more important factor for some stars than others. In particular, they discovered that flares from M0-M4 stars — cool, red stars like Betelgeuse — were more likely to strip an orbiting planet’s atmosphere. 

The duo determined that more frequent, lower energy flares in the extreme ultraviolet region (XUV) of the electromagnetic spectrum were more effective at stripping a planet’s atmosphere and thus reducing its habitability than less frequent, higher energy outbursts. XUV radiation strikes a planet’s atmosphere heating it. This causes hydrodynamic escape, pushing out light atoms first, which through collision and other drag effects also pull out heavier molecules. 

“We find that for most stars, luminosity-induced escape is the main loss mechanism, with a minor contribution from flares,” Atri explains. “However, flares dominate the loss mechanism of around 20 per cent of M4–M10 stars.

“M0–M4 stars are most likely to completely erode both their proto- and secondary atmospheres, whilst M4–M10 stars are least likely to erode secondary atmospheres.”

The study also highlights the fact that better modelling of the factors that affect an exoplanet’s atmosphere is needed. Determining the systems and planets most likely to harbour life will play an important factor in selecting targets for the upcoming James Webb Space Telescope — set to launch on October 31st 2021 — and the ESO’s Extremely Large Telescope (ELT) currently under construction in the Acatma desert, Chile. 

“The next research step would be to expand our data set to analyze stellar flares from a larger variety of stars to see the long-term effects of stellar activity, and to identify more potentially habitable exoplanets,” adds Atri.

The researcher also points out that the continued investigation of how planets lose their atmosphere could also focus on a target closer to home, our nearest neighbour, Mars. “Since it is extremely difficult to observe the escape process in exoplanets, we are planning to study this phenomenon in great detail on Mars with the UAE’s Hope mission,” the researcher says, explaining how observations from Mars missions can be used to better understand atmospheric escape and how this knowledge can be applied to exoplanets.“We will then apply our understanding of atmospheric escape to exoplanets and estimate the impact of extreme UV radiation on planetary habitability.”

An artist’s illustration of UAE’s Tess probe approaching the surface of Mars. Atri believes this investigation could yeild important data about exoplanet habitability.
(Mohammed bin Rashid Space Centre)

Further to the question of habitability, the study begins to address the wider question of the dynamics of stars and their planetary systems and the evolution of such arrangements. “Given the close proximity of exoplanets to host stars, it is vital to understand how space weather events tied to those stars can affect the habitability of the exoplanet,” Atri concludes. “Stars and planets are very tightly coupled in a number of ways and an improved understanding of this coupling are absolutely necessary to find habitable planets in our Galaxy and beyond.”

Atri. D., Carberry Morgan. S. R., [2020], ‘Stellar flares versus luminosity: XUV-induced atmospheric escape and planetary habitability,’ Monthly Notices of Royal Astronomical Society: Letters.

Perspective view of ancient river valley network on Mars. Credit: ESA.

Spectacular new images show Martian ancient river systems

Perspective view of ancient river valley network on Mars. Credit: ESA.

Perspective view of an ancient river valley network on Mars. Credit: ESA.

Mars is cold, barren, and totally inhospitable — but it wasn’t always so. We now know that the red planet was once wet, hosting a thick atmosphere under which huge rivers, even oceans, existed for millions of years. What’s more, a 2018 observation suggests that liquid water may still lurk in some isolated locations on Mars, such as in a 20 kilometer-wide subglacial lake that lies just 1.6 kilometers beneath the surface, near the south pole of Mars.

Some of the remnants of this watery past were first proposed by Italian astronomer Giovanni Schiaparelli, who observed mysterious straight lines along the planet’s equatorial regions in 1877. Schiaparelli called them canali (canals). However, what he saw was merely an optical illusion produced by the lens of his telescope. But, ironically, there really are canali, or watercourses, on Mars. It was only much later, with the advent of high-resolution telescopes and after we sent spacecraft to Mars, that this became evident. Now, a set of spectacular images released by the European Space Agency (ESA) shows some of the clearest evidence of ancient Martian rivers.

The images, captured by ESA’s Mars Express satellite, focus on a single region — a system of valleys located in the southern highlands of Mars, east of a huge impact crater called Huygens and north of Hellas, which is the largest impact basin on the red planet.

Credit: ESA.

Topographic view of an eroded valley system on Mars. Credit: ESA.

According to ESA scientists, the branching, desiccated system of trenches and valleys were actually carved by flowing water, and are likely 3.5 to 4 billion years old. The topography of the region suggests that water used to flow downhill from the north (right-hand side in the images) to the south (left-hand side on the images). The river system, which follows a dendritic pattern akin to tree branches or brain cells, carved out valleys up to 2 km (1.2 miles) across and 200 meters deep (650 ft.).

The valleys that we can see today have undergone heavy erosion since they formed, which is most visible in the form of the fragmented and smoothed valley rims. In the ESA images, you can see such signs of erosion cutting valleys from east to west.

The similarities to river systems here on Earth is striking. One can see various channels splitting from a central valley, forming tributaries, which can split again on their journey downstream. In this particular case, the branching channels were likely formed by surface water runoff from a river combined with extensive rainfall.

Satellite picture of the Grand Canyon, and Colorado River in the Grand Canyon — in northern Arizona. Credit: Wikimedia Commons.

Scientists would now like to know where all of this water came from. Was it rain, groundwater, melting glaciers, or all of them combined? This leads us to an even more important question: given its wet and warm past, could life have appeared on Mars like it did on Earth? This will actually be the main object of inquiry for the upcoming ExoMars mission — a collaboration between ESA and Russia which will land a rover named after Rosalind Franklin and a surface science platform on Mars. The rover will be tasked with drilling below the surface in search of microbial life — the very first mission of its kind. In the future, ESA would like to embark on an even more ambitious mission that might one-day return samples from Mars to Earth.

An artist conception of what the system around Kepler-186f could look like. Credit: NASA AMES/SETI INSTITUTE/JPL-CALTECH.

Search for alien life needs to be integral to NASA missions in the future, new report says

An artist conception of what the system around Kepler-186f could look like. Credit: NASA AMES/SETI INSTITUTE/JPL-CALTECH.

An artist conception of what the system around Kepler-186f could look like. Credit: NASA AMES/SETI INSTITUTE/JPL-CALTECH.

Although we’ve yet to find life outside planet Earth, astrobiology has certainly come a long way in the past decade alone. Our once crude assumptions are now more finessed and, thanks to the Kepler Space Telescope, we now know of thousands of exoplanets, some potentially habitable and only a couple light-years away. Bearing recent developments in mind, a new congressionally mandated report from the National Academies of Sciences, Engineering, and Medicine outlines some of the key steps NASA needs to take in order to bring alien hunting to the next level.

A plan to hunt alien life

The 196-page report starts by making a point of the fact that recent scientific advances have provided opportunities to strengthen the role of astrobiology in NASA. For instance, NASA’s Curiosity rover and Mars Reconnaissance Orbiter (MRO) have found evidence of organic molecules, atmospheric methane, briny surface water, and even an underground Martian lake filled with liquid water. Elsewhere, on Saturn’s moons Enceladus and Europa, scientists found evidence of plumes that shoot up hundreds of miles and which contain water and other organic compounds. In fact, it’s Europa — and not Mars — that is the most promising place where scientists think we’ll find life outside our planet.

It was also recently that biologists found strange Earth lifeforms which live deep underwater or underground, with no direct contact with the sun’s energy input. This means that life may be less capricious than once thought.

The committee that authored the new report, which is chaired by the University of Toronto’s Barbara Sherwood Lollar, claims that we need to expand our search for biosignatures. To this aim, they propose compiling a more “sophisticated catalog and framework will be important to enhance our ability to detect both life that might be similar to terrestrial life, and potential life that differs from life as we know it.”

In particular, the authors of the report call for NASA to focus on exploring the possibility of finding life below the surface of a planet or moon. They also recommend that NASA seeks to deploy better technologies, such as powerful telescopes and starlight-blocking instruments capable of more complex probing of alien planets.

But accurately finding and interpreting biosignatures will be a challenge. For instance, many biosignatures can be produced by abiotic chemical reactions. Methane is often touted as an important byproduct of biological activity, but it could very well be produced by non-biological processes.

The report is also careful to mention how such an ambitious mission is actually a planetary goal. NASA needs to build or strengthen collaborations with other institutions and private organizations, the authors note.

Along with a similar survey of exoplanets released last month, the new report will be included into two decadal surveys covering astronomy, astrophysics, and planetary sciences. These decadal surveys ought to form the backbone of NASA’s decision-making process about which missions to pursue or prioritize.

It Is Possible Jupiter Could Support Life, Scientists Say

Jupiter and its shrunken Great Red Spot. Credit: Wikimedia Commons.

Jupiter and its shrunken Great Red Spot. Credit: Wikimedia Commons.

A new factor has been added to the debate on whether or not living organisms could exist on Jupiter. You probably know Jupiter is a Jovian planet, a giant formed primarily out of gases. So how could alien life be able to exist in an environment where most of the phases of matter are absent? The answer is simply found in the element of water.

Within the rotating, turbulent Great Red Spot, perhaps Jupiter’s most distinguishable characteristic, are water clouds. Many of the other clouds in this enormous perpetual storm are comprised of ammonia and/or sulfur. Life theoretically cannot be sustained in water vapor alone; it thrives in liquid water. But according to some researchers, the fact alone that water exists in any form on the planet is a good first step.

The Great Red Spot is still a planetary feature which stumps much of the scientific community today. As it has been observed for the past century and a half, the Great Red Spot has been noticeably shrinking. The discovery of water clouds may lead to a deeper understanding of the planet’s past, including whether or not it might have sustained life, as well as weather-related information.

Some scientists have pondered the possibility that, due to the hydrogen and helium content in its atmosphere, Jupiter could be a diamond-producing “factory.” They have further speculated that these diamonds could enter into a liquid state and a rainfall of liquid diamonds would be in the Jovian’s weather forecast.

Likewise, the presence of water clouds means that water rain (a liquid) is not entirely impossible. Máté Ádámkovics, an astrophysicist at Clemson University in South Carolina, had this to say on the matter:

“…where there’s the potential for liquid water, the possibility of life cannot be completely ruled out. So, though it appears very unlikely, life on Jupiter is not beyond the range of our imaginations.”

Scientists are acting accordingly, researching the part which water plays in the atmosphere and other natural systems on Jupiter. They remain skeptical but eager to follow up on the new discovery. They shall also strive to find out just how much water the planet really holds.

Dark matter may be a manifestation of extremely advanced alien life, researchers suggest

Our limited understanding of dark matter and the fact that we’re focusing on the wrong things might be preventing us from discovering alien life.

This collage shows NASA/ESA Hubble Space Telescope images of six different galaxy clusters, with the distribution of dark matter colored in blue.

A Cosmic Gorilla

You know that experiment where you’re supposed to count the number of basketball passes, and you’re so focused on the ball that you don’t even see a bear moving through the picture? Researchers believe something similar might be happening on a cosmic scale. We’re so focused on one thing that we’re completely missing the other — and in this case, ‘the other’ might mean alien signals.

Writing in the journal Acta Astronautica, neuropsychologists Gabriel de la Torre and Manuel García, from the University of Cádiz, say that when it comes to detecting alien signals, we might be looking in the wrong direction. They say that we’re looking for aliens that act similarly to us when that might really not be the case.

“When we think of other intelligent beings, we tend to see them from our perceptive and conscience sieve; however we are limited by our sui generis vision of the world, and it’s hard for us to admit it,” says De la Torre, who prefers to avoid the terms ‘extraterrestrial’ or aliens by its Hollywood connotations and uses more generic terms, such as ‘non-terrestrial’.

“What we are trying to do with this differentiation is to contemplate other possibilities,” he says “for example, beings of dimensions that our mind cannot grasp; or intelligences based on dark matter or energy forms, which make up almost 95% of the universe and which we are only beginning to glimpse. There is even the possibility that other universes exist, as the texts of Stephen Hawking and other scientists indicate.”

The awareness test that inspired the study. Try to count the number of basketball passes. Did you also catch something out of the ordinary?

Hardwired to miss it

In order to test their hypothesis, they had 137 people distinguish aerial photographs with artificial structures (such as buildings or roads) from others with natural elements (such as mountains or rivers). In one of the images, a tiny character disguised as a gorilla was inserted to see if the participants noticed. As expected, participants tended to miss the gorilla. It’s normal because we’re hardwired to miss it — we’re looking for something else. Similarly, if we’re looking for a specific kind of signal, we might completely miss an unrelated type of signal, one we weren’t expecting.

“If we transfer this to the problem of searching for other non-terrestrial intelligences, the question arises about whether our current strategy may result in us not perceiving the gorilla,” stresses the researcher, who insists: “Our traditional conception of space is limited by our brain, and we may have the signs above and be unable to see them. Maybe we’re not looking in the right direction.”

In another example presented in the article, researchers showed participants an apparently geometric structure that can be seen in the images of Occator — an impact crater of the dwarf planet Ceres, famous for its bright spots. Inside the crater appears a strange structure, looking like a square inside a triangle. The point researchers were trying to make is that we sometimes see patterns that just aren’t there, due to the way our brains are wired.

“Our structured mind tells us that this structure looks like a triangle with a square inside, something that theoretically is not possible in Ceres,” says De la Torre, “but maybe we are seeing things where there are none, what in psychology is called pareidolia.”

Image Credits: NASA / JPL-CaltechClose

But the opposite might also be happening, they say. We might have the signal right in front of our eyes, and simply miss it — kind of like a cosmic gorilla effect.

Types of civilizations

We’re not really sure what to expect in terms of potentially advanced alien species, but the most commonly used scale is the Kardashev scale, proposed by Russian astrophysicist Nikolai Kardashev. The scale has three main categories, and it focuses on different stages of energy capture and use, which seems to be a vital requirement for an advanced species:

  • A Type I civilization (a planetary civilization) can use and store all of the energy which reaches its planet from the parent star.
  • A Type II civilization (a stellar civilization) can harness the total energy of its planet’s parent star and use it on a planet.
  • A Type III civilization (a galactic civilization) can control energy on the scale of its entire host galaxy.

If you’ll look at it closely, you’ll see that humans aren’t really even on a Type I level yet, so the Kardashev scale has been extended, both upwards and downwards, including:

  • A Type 0 civilization (humans) that harvests a significant part of its planet energy, just not yet to its full potential.
  • A Type IV civilization (a universal civilization) that can control energy on the scale of the entire universe. This is already a virtually indestructible civilization. This hypothetical civilization would be able to interact with and harvest dark matter and dark energy.
  • A type V civilization (a multiversal civilization) — this already steps into the realm of metaphysics and assumes there is more than one universe, and a civilization that’s able to span and populate several universes.
  • A type VI civilization (deities) that would have the ability to interact with universes outside of time and space, similar in concept to an absolute deity.

Already, it’s becoming quite clear that we don’t even know how to understand very advanced alien civilizations, assuming that they exist. We might be able to understand a Type 0, I, or II civilization, assuming that they do share some similarities with us. But should we come across the higher levels of civilization, would we even realize what we’re looking at? This is what de la Torre and Garcia are asking. For all we know, dark matter and dark energy might hold the traces of such an advanced civilization. Of course, the researchers themselves admit the inherent shortcomings when you’re classifying something you know nothing about.

“We were well aware that the existing classifications are too simplistic and are generally only based on the energy aspect. The fact that we use radio signals does not necessarily mean that other civilizations also use them, or that the use of energy resources and their dependence are the same as we have,” the researchers point out, recalling the theoretical nature of their proposals.

The duo also proposes a different civilization scale, with 3 types. Type 1 is essentially ours, ephemeral, vulnerable to a planetary cataclysm, either natural or self-made. Type 2 is characterized by the longevity of its members, able to explore galaxies and overall much more durable. Type 3, as you’d expect, would be constituted by exotic creatures with eternal or near-eternal life, with an absolute dominion over the universe.

Naturally, this is all a bit speculative. We don’t really know whether we’re looking for the right thing or not, we don’t even know if there is a right thing or not. How likely are we to miss an alien signal, in the case that it exists? Impossible to tell right now. So this study definitely goes a bit ‘out there’, but it poses some intriguing questions.

If anything, the main takeaway is that we should perhaps take a step back and reconsider what alien life might look like. In other words, we shouldn’t only be counting the passes — we should keep an eye out for any gorillas.

Journal Reference: Gabriel G. De la Torre, Manuel A. Garcia. The cosmic gorilla effect or the problem of undetected non terrestrial intelligent signals. Acta Astronautica, 2018; 146: 83 DOI: 10.1016/j.actaastro.2018.02.036

Why Stephen Hawking Was Afraid of Aliens

Young Stephen Hawking.

Professor Stephen Hawking, the theoretical physicist hailed as one of the most brilliant scientists of the modern age, had genuine anxieties. Thus, intelligence does not necessarily reject fear. Hawking had one fear in particular which deserves noting, namely humanity’s encounter with advanced alien life.

Several of the late physicist’s theories have been shown to be quite accurate and are widely accepted in the scientific community. When he spoke (through his speech synthesizer) people gave ear and were attentive. Like any man, he too had his faults both public and personal. But simply because the man has passed away, does not mean we should disregard what he did and said during his time on Earth.

He made numerous predictions about the present and future problems that the human race faces, involving issues such as overpopulation and artificial intelligence. Perhaps one of his most intriguing and logically-stated beliefs was a concern for detrimental interaction between human beings and extraterrestrial beings.

Unlike astrophysicist Carl Sagan, who was rather optimistic about extraterrestrial contact, Hawking worried about the effects such contact might have on our race, even though the Professor assisted in founding projects to seek intelligent alien organisms. Some may fear aliens as they are depicted in sci-fi and horror stories: ugly creatures capable of taking over human beings and using them as their hosts.

The physical appearance of hypothetical aliens is not what alarmed Stephen Hawking. It was something a bit more sinister. In short, he apparently was cautious of entertaining alien contact because of the possibility that intelligent alien civilizations may want to dominate our race. They might do this either by enslaving people or slaughtering them, or both.

He has related these concerns publicly as early as 2010. In 2016, he speculated that if Earth received a signal of alien origins “we should be wary of answering back.” He further argued this point by employing historical references. “Meeting an advanced civilization could be like Native Americans encountering Columbus,” he said. “That didn’t turn out so well.” Sometime in the future, if we’re not cautious in the search for alien life, humans might rue ignoring Stephen Hawking’s worries about extraterrestrials.

The Search for Alien Life: We Have Been Looking in the Wrong Places

SETI Initiative. Source: Traces Online.

Humanity has pondered the existence of alien life for centuries. However, it has been in just the past 100 years or so that modern science has backed some of this thinking. Scientists of the late 1800’s and early 1900’s believed that objects appearing on the surface of Mars were canals constructed by aliens. Particularly, astronomer Percival Lowell believed this concept and promoted it in works such as the book Mars As the Abode of Life (1908).

This belief in the scientific community led to a huge amount of pop culture based around the concept of extraterrestrials. This has resulted in some people even believing in the existence of aliens like the ones in the movies. Who knows? They could be out there. But some wonder how probable their existence is.

With aliens constantly being depicted in entertainment, even after the Martian alien canal hypothesis was busted, scientists considered communicating with otherworldly life forms. The first scientists looking for a close encounter believed the best bet was to use radio waves as the communication medium. The first of such proposed experiments was conducted in 1960 by astronomer Frank Drake.

One of the most eye-opening quotes about extraterrestrial alien life comes from the book Time for the Stars by Alan Lightman. The author states, “Are we alone in the universe? Few questions are more profound… Extraterrestrial contact would forever change the way we view our place in the cosmos” (Lightman 21).

Drake would definitely not be the last scientist to attempt to summon a response from an alien. But this was the first modern example of tests which would now be referred to as part of SETI, the search for extraterrestrial intelligence. In 1980, to bring more of a public interest to SETI, the legendary astrophysicist, astronomer, and astrobiologist Carl Sagan and several others formed The Planetary Society. In more recent years, other programs with goals similar to SETI’s have been established such as METI, messaging extraterrestrial intelligence.

Apart from radio waves, humans have tried other ways of communicating with hypothetical aliens. One example is a plaque which was attached to the Pioneer 10 probe in 1972. This plaque would be a unique kind of “message in a bottle,” except the ocean it was doomed to drift in was far more vast than any sea on Earth. It was inquired of Carl Sagan about sending such a message several months before the scheduled departure of the craft. So Sagan went to work, and assisting him with this undertaking was none other than Frank Drake, the man who had conducted the first modern SETI tests in 1960. The fruit of numerous labors and laborers, the Pioneer 10 plaque that was sent into space depicted a man and a woman and several objects. Through the imagery, the scientists were trying to give any aliens who might see this plaque an idea of what humans are like and where Earth is located.

This could be the first big mistaken researchers are making. They are looking to make contact. They are putting their faith in a sci-fi movie concept. What these scientists are attempting to do is call up and have a conversation with an alien or, better yet, a race of aliens. This is not to say that SETI is pointless, but it might not be the most opportune method for seeking alien life.

Perhaps scientists should strive to discover life in its simpler forms. As Lee Billings of Scientific American states in a recent article, if you were able to travel to another planet it is likely “you would find a planet dominated by microbes rather than charismatic megafauna.” Many scientists are now suggesting microscopic organisms could be more plentiful throughout the cosmos than macroscopic creatures.

Microbes Are a Realistic Form of Alien Life. Source: Joi Ito’s PubPub.

A specific search for such minuscule life forms is not a new practice. Bacteria are, of course, microbes. Astrobiologists like Richard Hoover and Dave McKay have examined certain meteorites. Some of the microscopic structures found embedded in or on the space relics resemble bacteria. They have released their findings in past years. They have admitted that even though the fossilized structures appear to be remnants of bacteria there is still some skepticism as to whether those structures are alien in origin. This is because bacteria from Earth could have been attached to the meteorites once they entered our atmosphere.

So how do scientists narrow down the search for alien life even further? Billings’ piece may give us the best idea available at the moment. He informs his readers that one of oxygen’s properties is that it tends to descend from an atmosphere in the form of mineral oxides. It does not remain in its gaseous phase for long. Because of its nature, in an atmosphere such as Earth’s, the oxygen has to be reinstituted on a regular basis.

Astrobiologists have to accept oxygen may be one of the least familiar elements they come upon when studying potential life-supporting bodies. For example, atmospheric chemist David Catling has said the atmosphere of a world dominated by microscopic life could be largely comprised of methane and carbon dioxide gases. Keeping this in mind, this will hopefully narrow down the most likely planet candidates for life.

The researchers imagine a complex alien called the 'Octomite' which is comprised of a hierarchy of entities, where each lower level collection of entities has aligned evolutionary interests such that conflict is effectively eliminated. Credit: University of Oxford.

Aliens could be more like us than we think, say Oxford scientists

Humans might have more in common with our yet inconspicuous galactic neighbors than we thought. According to scientists at the University of Oxford, natural selection and evolutionary theory seem to favor organisms that behave similarly to those found on Earth.

The researchers imagine a complex alien called the 'Octomite' which is comprised of a hierarchy of entities, where each lower level collection of entities has aligned evolutionary interests such that conflict is effectively eliminated. Credit: University of Oxford.

The researchers imagine a complex alien called the ‘Octomite’ which is comprised of a hierarchy of entities, where each lower level collection of entities has aligned evolutionary interests such that conflict is effectively eliminated. Credit: University of Oxford.

Astrobiologists — scientists concerned with the study of life outside Earth — have their work cut out for them in this day and age. Since no alien organisms have been found yet, their field of study is riddled in uncertainties and speculations. Given the vastness of the cosmos and what we know about potentially habitable planets, the odds of Earth being the only planet in the universe capable of hosting life look very slim. It seems extremely unlikely that life on Earth is unique.

At the same time, making predictions about alien life is challenging, especially when you have one example to work with: life on Earth. Previously, scientists have predicted what alien life might look like by extrapolating what we know about organisms on Earth, as well as the chemistry, geology, and physics on our planet.

But these “past approaches in the field of astrobiology have been largely mechanistic,” says Sam Levin, a scientist at Oxford’s Department of Zoology. He and colleagues have gone a different route that’s more principle driven and less dependent on Earth-centered assumptions.

“In our paper, we offer an alternative approach, which is to use evolutionary theory to make predictions that are independent of Earth’s details. This is a useful approach, because theoretical predictions will apply to aliens that are silicon based, do not have DNA, and breathe nitrogen, for example,” Levin said in a press release. 

The researchers did assume at least one process that’s fundamental to Earthlings governs alien life as well: natural selection. Starting from natural selection as a framework, the researchers built a model of extraterrestrial evolution.

alien evolution

These illustrations represent different levels of adaptive complexity Different levels of adaptive complexity triggered by ‘major transitions’. (a) A simple replicating molecule, with no apparent design. This may or may not undergo natural selection. (b) An incredibly simple, cell-like entity. Even something this simple has sufficient contrivance of parts that it must undergo natural selection. (c) An alien with many intricate parts working together is likely to have undergone major transitions. Credit: University of Oxford

More of the same

Though the origin of life on Earth is still a matter of debate, we know that the very first creatures were simple, single-celled organisms. Over the course of countless generations, some of these single-celled organisms merged, learned to cooperate, and formed multi-cellular organisms. Complexity jumped in steps caused by a handful of events known as ‘major transitions’. The transitions from prokaryotes to eukaryotes or from asexual clones to sexual populations are some prime example. Both evolutionary theory and empirical data suggest that extreme conditions say sudden climate change, are required to drive a major transition.

With this framework in mind, the Oxford scientists made some predictions about what alien life might look like, complete with some illustrations to boot.

Of course, no one can say if aliens walk on two legs or have four eyes. The Oxford team, however, says that there’s a level of predictability to evolution which would cause aliens to look at least a bit like us, they reported in the International Journal of Astrobiology. In other words, they’d look and function more similarly to humans than differently.

“Like humans, we predict that they are made-up of a hierarchy of entities, which all cooperate to produce an alien. At each level of the organism there will be mechanisms in place to eliminate conflict, maintain cooperation, and keep the organism functioning. We can even offer some examples of what these mechanisms will be,” Levin said.

“There are potentially hundreds of thousands of habitable planets in our galaxy alone. We can’t say whether or not we’re alone on Earth, but we have taken a small step forward in answering, if we’re not alone, what our neighbours are like,” he added.

El Tatio, Chile. Credit: Pixabay, falco.

Martian minerals might bear signatures of ancient life

El Tatio, Chile. Credit: Pixabay, falco.

El Tatio, Chile. Credit: Pixabay, falco.

Almost ten years ago, in 2007, the old timer Spirit rover found opaline silica for the first time on Mars. These rocks are evidence of past hydrothermal or volcanic activity – some kind of heated geological interaction. The discovery marked a turning point in Martian geology, but afterwards, not much consideration was given  to the Home Plate — a plateau of layered rocks that the rover explored in its third year on the Red Planet — and the Gusev Crater where the silica rocks were found. Many years later, researchers from Arizona State University say the features in the rocks found in Gusev Crater are strikingly similar to those collected from active hot springs in Tatio, northern Chile.

Finding signs of past life is still something

“Although fully abiotic processes are not ruled out for the Martian silica structures, they satisfy an a priori definition of potential biosignatures,” the researchers wrote in the study.

Initially, everyone thought the opaline silica deposits found by the Spirit rover formed billions of years ago by fumarole-related acid-sulfate leaching. What they missed, however, were the nodular and millimeter-scale digitate opaline silica structures typically formed by microorganisms living in hot, mineral-rich waters.

Steve Ruff, a planetary scientist at Arizona State University, stumbled one day across a paper describing El Tatio, an incredible hydrothermal system 14,000 feet above sea level. El Tatio is littered with hot springs and geysers channels which contain deposits of opaline silica. Moreover, the site has a low precipitation rate, high mean annual evaporation rate, common diurnal freeze-thaw and extremely high ultraviolet irradiance. All of this makes El Tatio very Mars-like. Ruff was on to something.

The scientist, along with colleagues, traveled to Chile to inspect El Tatio with his own eyes. They collected samples and performed both spectral analysis and high-res imaging. What they later found was that the silica minerals from El Tatio form in shallow, hydrothermal waters. The opaline silica from the site that most closely resemble minerals from Mars were those that were formed in the presence of microbes. Specifically, the nodular tiny features on the minerals form when biofilms — clumped-together mats of microorganisms — stick to them.

Opaline silica: on the left samples collected from Mars, El Tatio on the right. Credit: ASU.

Opaline silica: on the left samples collected from Mars, El Tatio on the right. Credit: ASU.

“Our results demonstrate that the more Mars-like conditions of El Tatio produce unique deposits, including biomediated silica structures, with characteristics that compare favorably with the Home Plate silica outcrops. The similarities raise the possibility that the Martian silica structures formed in a comparable manner,” the researchers noted at the end of their travels and studies.

 

“Because we can neither prove nor disprove a biological origin for the microstromatolite-like digitate silica structures at Home Plate, they constitute a potential biosignature according to this definition,” they concluded.

On May 9, 2009, the Spirit rover boggled down, trapped in Mars’ soft soil. The rover continued to function as a stationary measurement platform until it was discontinued in May. 2011. That being said, our only shot of finding out for real whether the opaline silica from Gusev Crater genuinely bears signs of life is to send another rover. NASA has such a mission planned for 2020 but it’s yet to consider a drop off location. In light of these recent findings, maybe Gusev Crater might prove appealing.

 

Artist impression of how the laser-fluorescence instrument could operate on Mars. Credit: NASA

New laser tech could be the life-sniffing ‘nose’ for NASA’s next Mars rover

Artist impression of how the laser-fluorescence instrument could operate on Mars. Credit: NASA

Artist impression of how the laser-fluorescence instrument could operate on Mars. Credit: NASA

One of the biggest concerns NASA scientists looking for alien life on Mars have is that they might one day find biological signatures — only to later find these were actually contaminants brought from Earth. An upgrade to a laser radar called LIDAR, typically used to monitor air quality or map large areas, could solve this concern and make investigations a lot more efficient, say NASA scientists.

A light nose

The instrument is called  Bio-Indicator Lidar Instrument, or BILI. Branimir Blagojevic, now a NASA technologist at the Goddard Space Flight Center in Greenbelt, used to work for the company that first made the device. At NASA, Blagojevic used his experience and skills to turn the technology into a working prototype that shows that the same instruments used to monitor biohazards in public places could be effective at detecting organic biosignatures on Mars, too.

LIDAR is a remote sensing instrument that is very similar in working principle to radar. However, instead of radio waves, LIDAR uses light shone by lasers to measure distances from a target, but also determine the composition of particles in the air.

BILI is essentially a fluorescence-based lidar that can detect chemicals based on their fluorescent emissions. Fluorescence-based sensing instruments have been widely employed by NASA in its climate research, but soon the space agency will also use it in planetary studies. “If the agency develops it, it will be the first of a kind,” Blagojevic said.

Because it can detect small levels of complex molecules in real time from a distance of several hundred meters, BILI could serve as the nose of NASA’s next rover mission, planned for 2020. The instrument can be used to scan the bio-signatures in plumes above recurring slopes which are very challenging to travel for a rover. It could also be targeted on ground-level aerosols with no risk of sample contamination.

For now, Blagojevic envisions BILI positioned on a rover’s mast. Initially, the instrument first scans for dust plumes, then, once detected, the command is issued for two ultraviolet lasers to shine light pulses at the dust. The illumination causes the dust clouds to resonate or fluoresce. It’s then only a matter of analyzing this signal and comparing it with known signatures from a database to detect organic particles. The same analysis also reveals the particles’ size.

“If the bio-signatures are there, it could be detected in the dust,” Blagojevic said in a statement for the press.

“This makes our instrument an excellent complementary organic-detection instrument, which we could use in tandem with more sensitive, point sensor-type mass spectrometers that can only measure a small amount of material at once,” Blagojevic said. “BILI’s measurements do not require consumables other than electrical power and can be conducted quickly over a broad area. This is a survey instrument, with a nose for certain molecules.”

Why stop at a rover, though? Indeed, NASA has plans to mount BILI or a later version onto spacecraft. NASA could then significantly increase its odds of detecting biosignatures in the solar system.

Next for Blagojevic and colleagues is to refine their design. The goal is to make BILI smaller, more rugged, and more sensitive to a broad range of organic particles.

The reason why we haven’t found alien life yet might be because we’re searching too soon

An artist’s impression of a planet with two exomoons orbiting in the habitable zone of a red dwarf. Credit: NASA // Wikimedia Commons

In our very own galaxy, there are up to 400 billion stars and around 100 billion planets, out of which an estimated 40 billion Earth-like exoplanets should be orbiting sun-like stars or red dwarfs in a habitable zone. Faced with this sort of numbers for only for one galaxy — our own — many scholars naturally assert that Earth ought not to be the sole life-bearing planet out there. Yet, for better or worse, our giant radio telescopes haven’t picked up any artificial alien signals. Faced with such uncertainties, scientists nowadays are going wild with all sorts of educated assumptions and hypotheses in an effort to unravel this existential dilemma.

A head start

While previous research seems to indicate the chances of Earth being the only place in the galaxy capable of fostering life are slim, one team of astronomers and physicists led by Harvard University’s Avi Loeb are exploring an alternate route. Their research concludes that planets orbiting dim stars called red dwarfs are the best place to look for extraterrestrial life. The catch: life shouldn’t spring in these sort of places for another 10 trillion years. For comparison, the universe is thought to be 13.7 billion years old. That’s a lot of waiting time. It follows, that maybe — just maybe — life on Earth is singular, or among the very first.

Red dwarfs are by far the most common stars in the universe, comprising about three-fourths of all stars based on space telescope observations made so far. Red dwarf stars typically have a mass of between 7.5% and 40% of the Sun, and this lower mass means that red dwarfs have a cooler surface temperature than the Sun, typically around 3,500 Kelvin (3,230 degrees Celsius) compared to over 5,750 Kelvin (5,475 degrees Celsius) for the Sun.

Artist's conception of a red dwarf, the most common type of star in the Sun's stellar neighborhood, and in the universe. Although termed a red dwarf, the surface temperature of this star would give it an orange hue when viewed from close proximity. Credit: Wikimedia Commons

Artist’s conception of a red dwarf, the most common type of star in the Sun’s stellar neighborhood, and in the universe. Although termed a red dwarf, the surface temperature of this star would give it an orange hue when viewed from close proximity. Credit: Wikimedia Commons

A potentially habitable planet — meaning it revolves around a stable orbit and can sustain liquid water and an atmosphere — from a red dwarf system thus has to be a lot closer to the energy source (the red dwarf) than an Earth-like planet around a sun-like star. However, red dwarfs can last for up to 1,000 times longer than sun-like stars because they need far less fuel to sustain the nuclear fusion.

Loeb and colleagues calculated the relative formation probability per unit time of habitable Earth-like planets starting from the first stars and continuing to the distant cosmic future. One core assumption was that habitable planets need to sustain “life as we know it” — carbon-based, water-dependent and within a certain temperature range. Then, assuming life is indeed possible to form around red dwarfs, the researchers found that extraterrestrial life is 1,000 times more likely to arise in the distant future than it is today. A very distant future, as outlined earlier.

“That’s surprising,” says Loeb. “It means that life around the sun is probably a bit early.”
“If it turns out that low-mass stars are able to support life, then we are special because we are one of the early forms of life,” Loeb says.

Whether red dwarfs can host any life whatsoever is still a matter of debate. Because these stars are so dim, potentially habitable planets need to orbit very closely around their red dwarf parents, which might subject them to radiation and solar flares.

The upcoming Transiting Exoplanet Survey Satellite and James Webb Space Telescope could help settle this debate once they become operational and use their spectroscopic instruments to peer into the chemical makeup of plants orbiting red dwarfs. It might take anything from a decade to a couple of decades before this happens, though. Until then, Loeb’s hypothesis is both entertaining and somewhat depressing. No one likes to be the first comer to a party.

Jupiter’s moon Europa could have Earth-like oceans

If I asked you to guess where we have the best chances of finding life outside of Earth, you’d be hard pressed to think about Europa. But Jupiter’s frozen moon is beginning to look more and more attractive, and may even harbor an Earth-like ocean.

This enhanced-color view from NASA’s Galileo spacecraft shows an intricate pattern of linear fractures on the icy surface of Jupiter’s moon Europa.
Credits: NASA/JPL-Caltech/ SETI Institute

We’ve written extensively before about the life harboring possibilities of Jupiter’s moon, Europa. Beneath the frozen surface, Europa hosts a salty ocean. There are already some indications about the chemistry of that ocean and its life hosting capabilities. Now, a study from researchers at NASA’s Jet Propulsion Laboratory offered even more support for that theory.

The study compared Europa’s potential for producing hydrogen and oxygen with that of Earth, through processes that do not directly involve volcanism. The balance of these processes gives a key indication about the energy available in the system, energy that would be available for life to harvest. The study found that the amounts would be comparable in scale; on both worlds, oxygen production is about 10 times higher than hydrogen production. This means that the oceans on Europa may be very similar to the oceans on Earth, which in turn means that the rocky core of the satellite may be more complex and Earth-like than we previously thought.

[panel style=”panel-success” title=”Life on Europa” footer=””]- Jupiter’s satellite Europa has a liquid ocean beneath its frozen surface
– Europa’s ocean has similar chemical and energy characteristics to that of Earth
– This may hint at the satellite’s life-bearing possibilities, but this is only a piece of a bigger puzzle.[/panel]

Steve Vance, a planetary scientist at JPL and lead author of the study declared:

“We’re studying an alien ocean using methods developed to understand the movement of energy and nutrients in Earth’s own systems. The cycling of oxygen and hydrogen in Europa’s ocean will be a major driver for Europa’s ocean chemistry and any life there, just as it is on Earth.”

Of course, this is only one piece of a bigger puzzle – but it’s a very intriguing piece. Europa is thought to have a hot, iron core and an ocean underneath its thick crust of ice on the surface. Despite the cold temperatures on the surface of the planet, measurements indicate that the ocean is not only liquid, but actually warm, heated by the tidal stresses exerted on Europa by Jupiter as well as by radioactivity. The required substances and elements to harbor life are mixed and flowed through the ocean by the same powerful currents. So all in all, there’s a very good environment with a lot of potential of fostering life – quite possibly the best one we have in the solar system.

“The oxidants from the ice are like the positive terminal of a battery, and the chemicals from the seafloor, called reductants, are like the negative terminal,” said planetary scientist Kevin Hand, also from JPL. “Whether or not life and biological processes complete the circuit is part of what motivates our exploration of Europa.”

Jupiter’s moon, Europa, is believed to hide a deep ocean of salty liquid water beneath its icy shell. Now, a new Nasa study has revealed that this ocean may have an Earth-like chemical balance that could sustain life

There is also a very active water circuit, on a tectonic level. We know this because the icy crust on the surface lacks signs of impact craters, which means it’s constantly renewed. This process doesn’t require any volcanic activity.

“… if the rock is cold, it’s easier to fracture,” said Vance. “This allows for a huge amount of hydrogen to be produced by serpentinization that would balance the oxidants in a ratio comparable to that in Earth’s oceans.”

These tantalizing studies make a clear case for life-favoring conditions, but there are still plenty of factors which could paint an unfavorable picture for life to emerge. This is why we need to get a mission to Europa, to get some first-hand informations and get a clearer idea of whether this frozen satellite is as barren as we once thought, or if it is a hidden oasis of life.

Computer models confirm icy eruptions on Saturn’s Moon

A few years ago, the Cassini spacecraft made a surprising discovery: there are geysers erupting on Saturn’s moon Enceladus, spewing water and ice to great heights. However, the process which causes these geysers remained unknown or controversial. Now, scientists at the University of Chicago and Princeton University have pinpointed a mechanism through which Saturn’s tidal forces exert constant stress and cause long-term icy eruptions.

Ice and volcanoes

This enhanced color view of Enceladus shows much of the southern hemisphere and includes the south polar terrain at the bottom of the image. Scientists at the University of Chicago and Princeton University have published a new study describing the process that drives and sustains this moon of Saturn's long-lived geysers. Photo by NASA/JPL

This enhanced color view of Enceladus shows much of the southern hemisphere and includes the south polar terrain at the bottom of the image. Scientists at the University of Chicago and Princeton University have published a new study describing the process that drives and sustains this moon of Saturn’s long-lived geysers. Photo by NASA/JPL

Enceladus is is the sixth-largest moon of Saturn, measuring only 500 kilometers (310 mi) in diameter. Enceladus is covered by fresh, clean ice, reflecting almost all the sunlight that strikes it. However, Enceladus displays a surprisingly large variety of geological features, including rifts, canyons, grooves, ridges and fractures, likely caused by the stress exerted on the moon by its parent planet, Saturn. This stress also causes massive friction inside the planet, which led researchers to believe that there might be a liquid ocean under Enceladus’ frozen surface — and potentially, life. Disregarded once as frozen and barren wasteland, the moon is now one of the likeliest places to find extraterrestrial life.

But one big question still remained: why are these eruptions happening in the first place?

“On Earth, eruptions don’t tend to continue for long,” said Edwin Kite, assistant professor of geophysical sciences at UChicago, who led this study. “When you do see eruptions that continue for a long time, they’ll be localized into a few pipelike eruptions with wide spacing between them.”

Enceladus has multiple fissures along its south pole. These “tiger stripes” have been erupting for decades, and it’s strange that the geysers haven’t clogged up on themselves. Somehow, these icy eruptions kept going and going.

“It’s a puzzle to explain why the fissure system doesn’t clog up with its own frost,” Kite said. “And it’s a puzzle to explain why the energy removed from the water table by evaporative cooling doesn’t just ice things over.”

Kite suspected there was another source of energy, responsible for cleaning the site. Now, after creating several models of the site, they believe they’ve zoomed in on this factor:

“We think the energy source is a new mechanism of tidal dissipation that had not been previously considered,” Kite said. Kite and Princeton’s Allan Rubin present their findings the week of March 28 in the Early edition of the Proceedings of the National Academy of Sciences.

Life beneath a frozen moon

: Possible Hydrothermal Activity (Artist’s Concept)
This cutaway view of Saturn’s moon Enceladus is an artist’s rendering that depicts possible hydrothermal activity that may be taking place on and under the seafloor of the moon’s subsurface ocean, based on recently published results from NASA’s Cassini mission. Credits: NASA/JPL

Understanding this system is extremely important for astrobiological studies (the search for extraterrestrial life). As I mentioned above, Enceladus is one of the top candidates for extraterrestrial life. Kite even calls it “an opportunity for the best astrobiology experiment in the solar system,” and for good reason. Not only is it extremely likely that it hosts an ocean of liquid water, but Cassini’s data indicates that the icy volcanoes probably originate in a biomolecule-friendly oceanic environment.

The erupted plumes have been shown to have grains of silica-rich sand, nitrogen (in ammonia), nutrients and organic molecules, including trace amounts of simple hydrocarbons such as methane. All these are indicators of hydrothermal activity in Enceladus’ ocean; hydrothermal vents are generally regarded as ideal places for life to thrive. To make things even better, models indicates the large rocky core is porous, allowing water to flow through it to pick up heat.

Europa, one of Jupiter’s moons is in a very similar situation, and the team now wants to apply similar models for it.

“Europa’s surface has many similarities to Enceladus’s surface, and so I hope that this model will be useful for Europa as well,” Kite said.

Robotic exploration missions have been planned for both moons, but no clear timeline has been drawn.

NASA prepares for historic Cassini flyby

NASA is preparing for a historical approach to Enceladus, plunging its Cassini spacecraft deep through the icy spray coming from the ocean on Enceladus.

An Ocean and Geysers on Enceladus

A Cassini mosaic of degraded craters, fractures, and disrupted terrain in Enceladus’s north polar region. Image via Wikipedia.

After years and years of observations, deductions and scientific reasoning, NASA can now say with almost certainty that there is an ocean of liquid water on Enceladus, hidden beneath its frozen surface – which makes it a very interesting target for detecting alien life.

Enceladus is the sixth-largest moon of Saturn, measuring only 500 km in diameter. It’s covered in fresh, clean ice that reflects most of the sun waves that reach it, but it has long been believed that Saturn’s tidal forces cause a shear stress on Enceladus, which in turn causes friction and generates enough heat for water to remain liquid beneath the surface. In 2005, the Cassini spacecraft started multiple close flybys of Enceladus, revealing its surface and environment in greater detail. Among its most interesting findings, Cassini reported a water-rich plume venting from the south polar region of Enceladus; by now, over 100 geysers have been identified, spewing not only liquid water, but also volatiles and even solid material, such as salt (sodium chloride). This seems to indicate that Enceladus not only has a liquid ocean of water, but also hydrothermal activity – which also rises the chances of emerging life.

These geyser observations, along with the finding of escaping internal heat and very few (if any) impact craters in the south polar region, show that Enceladus is geologically active today; you can see tectonic features on its surface, most notably the above described “water volcanism“. There are also relatively crater-free regions filled with numerous small ridges and scarps, as well as fissures, plains, corrugated terrain and other crustal deformations.

This artist’s rendering showing a cutaway view into the interior of Saturn’s moon Enceladus. Image via NASA.

Flying by

It’s not the first time Cassini flew by Enceladus, but it’s the first time it will be plunging deep through a fountain of this water/ice spray.

“This daring flyby will bring the spacecraft within 30 miles (48 kilometers) of the surface of Enceladus’s south polar region,” NASA said in a statement.  “The encounter will allow Cassini to obtain the most accurate measurements yet of the plume’s composition, and new insights into the ocean world beneath the ice.”

The mission’s purpose is not to directly detect life, but rather to provide powerful new insights about how habitable the ocean environment is within Enceladus. Specifically, Cassini’s flyby will offer chemical and physical information about the hydrothermal activity, both about the water and the rock around it. The low altitude of the encounter is, in part, intended to afford Cassini greater sensitivity to heavier, more massive molecules, including organics. We will also find out whether the icy spurts are column-like, individual jets, or sinuous, icy curtain eruptions (or some combination of both, or something completely different). Researchers also want to see just how much material is ejected.

All in all, Cassini can’t figure out on its own if there is life on Enceladus – it wasn’t built for that. But it can do the next best thing – see if the conditions are suitable for life. Enceladus looks like one of the hottest places to find life in the solar system.