Tag Archives: Europa

Twinkle, twinkle, little … moon? Jupiter’s icy moon Europa glows in the dark, researchers find

Europa, the frozen but ocean-filled moon that orbits Jupiter is bombarded by a relentless flux of radiation. Day in and day out, Jupiter flings electrons and other particles towards it. These particles hit the ice and salt-rich surface of Europa, creating a soup of complex interactions that produce something otherworldly: they make Europa glow in the dark.

This artistic illustration of Jupiter’s moon Europa shows how the icy surface may glow on the side facing away from the Sun (like the Earth’s moon, Europa is tidally locked so one side always faces Jupiter and one side always faces away). Variations in the glow and the color of the glow itself could reveal information about the composition of ice on Europa’s surface. Credit: NASA/JPL-Caltech

A song of ice and radiation

Cold Europa is already a hotspot of interest for astronomers. Although it is a frozen desert on the surface, astronomers believe it harbors liquid water beneath its icy crust, and based on what we know about its chemical make-up, it seems like a promising candidate for hosting life in this subsurface ocean.

But while the inside of the planed may be teeming with life (it’s probably not teeming, but you know), the surface is interesting in its own right. NASA astronomer Murthy Gudipati and colleagues recreated some of the interactions on Europa’s surface in the lab, exposing salted ice to energetic electrons as they would expect from Jupiter. They found that these interactions trigger a process called electron-stimulated luminescence. Simply put, it glows in the dark.

It’s an unusual process. You may be tricked into thinking it’s common for moons to glow by looking at our very own moon, bright on the night sky. But our moon isn’t glowing, it’s merely reflecting light from the Sun. Meanwhile, Europa truly produces its own light, even on the side that’s turned away from the Sun.

The surface of Europa is covered in cracked and ridged ice. Imge credits: NASA/JPL

This is more than just a cool factoid that researchers have found about Europa. The work presented here is important for understanding Europa’s surface chemical composition and mineralogy, which in turn affect its habitability.

“We were able to predict that this nightside ice glow could provide additional information on Europa’s surface composition. How that composition varies could give us clues about whether Europa harbors conditions suitable for life,” said JPL’s Murthy Gudipati, lead author of the work published Nov. 9 in Nature Astronomy.

“If Europa weren’t under this radiation, it would look the way our moon looks to us—dark on the shadowed side,” Gudipati adds. “But because it’s bombarded by the radiation from Jupiter, it glows in the dark.”

What science is all about

The salty compounds react differently to the radiation and emit their own unique glimmer. By analyzing these glimmers at different wavelengths, astronomers can connect them to their “signatures” and assess the chemical make-up of the moon. This came as a bit of a surprise: researchers didn’t expect to see variations in the glow itself tied to different ice compositions. It was, the researchers call it, serendipity.

“Seeing the sodium chloride brine with a significantly lower level of glow was the ‘aha’ moment that changed the course of the research,” said Fred Bateman, co-author of the paper. He helped conduct the experiment and delivered radiation beams to the ice samples at the Medical Industrial Radiation Facility at the National Institute of Standards and Technology in Maryland.

The proposed robot lander on the surface of Europa (artistic depiction) during the Clipper mission. Image credits: NASA/JPL.

So far, the researchers haven’t made any new discoveries about the chemistry of Europa. We’ll have to wait for NASA’s upcoming Europa Clipper mission, which will observe the moon’s surface over multiple flybys. These flybys (and the planned robot lander) could map Europa’s chemistry and gain insights about the sub-surface ocean (especially its salinity).

It’s uncommon for a lab experiment to be help a space mission know what to prepare for, but this is exactly what science is all about, says Gudipati.

“It’s not often that you’re in a lab and say, ‘We might find this when we get there,'” Gudipati said. “Usually it’s the other way around—you go there and find something and try to explain it in the lab. But our prediction goes back to a simple observation, and that’s what science is about.”

Europa Clipper is set to launch in the mid-2020s and it’s set to be one of the most exciting missions of the decade as it will investigate a part of the solar system that’s promising in regards to extraterrestrial life. Researchers are now reviewing the findings to see how Clipper’s scientific toolkit could detect variations in the moon’s glow.

Journal Reference: Laboratory predictions for the night-side surface ice glow of Europa, Nature Astronomy (2020). DOI: 10.1038/s41550-020-01248-1 , www.nature.com/articles/s41550-020-01248-1

It’s official: There’s water on Jupiter’s moon Europa

NASA has confirmed that Jupiter’s moon Europa contains liquid water, making it one of the most promising places we know for extraterrestrial life.

At first glance, not much is happening on Europa. A small, frozen world orbiting Jupiter doesn’t seem like the most interesting place out there. But 40 years ago, the Voyager snapped an intriguing photo of the satellite: its frozen surface wasn’t stale and monotonous, it was cracked and sliced by different features, suggesting active and recent phenomena. Subsequent missions showed even more exciting things.

Despite being undoubtedly bombarded by meteorites, Europa’s surface is largely devoid of craters. This means that something must have erased or eroded them, suggesting some active geology. Not only is Europa active — it has some form of tectonics, and more impressively, it seems to have liquid water. The liquid water isn’t on the surface but rather beneath the frozen surface. The pattern of the cracks observed on Europa’s surface suggest that the frozen surface of the planet is not locked to the rest of the interior, which is exactly what you’d expect to happen if a layer of liquid were to exist beneath the surface.

To make things even more tantalizing, astronomers have observed something which seems to be plumes of water emerging from Europa. Some of the plumes are hundreds of kilometers high, adding even more evidence to the case for water on Europa.

Now, that case is essentially proven. Researchers looking from the W. M. Keck Observatory, atop the dormant Mauna Kea volcano in Hawaii, found a clear signature of water molecules.

“Essential chemical elements (carbon, hydrogen, oxygen, nitrogen, phosphorus, and sulfur) and sources of energy, two of three requirements for life, are found all over the solar system. But the third — liquid water — is somewhat hard to find beyond Earth,” said Lucas Paganini, a NASA planetary scientist who led the water detection investigation. “While scientists have not yet detected liquid water directly, we’ve found the next best thing: water in vapor form.”

Image credits: NASA / JPL.

Detecting the signatures of elements on other planets is much more difficult than on Earth. Naturally, Europa’s environment is very different from that of Earth. The main idea behind the study was to use a spectrograph to assess the chemical composition of Europa by measuring how molecules on the satellite interact with infrared light. Molecules such as water emit specific frequencies which can be used as signatures.

But when your telescope is based on Earth, all light would pass through the Earth’s atmosphere — which contains a lot of water on its own. Paganini’s team had to use complex modeling to simulate the conditions of Earth’s atmosphere and then subtract them from what they were seeing on Europa. It wasn’t an easy task, but in the end, the researchers were successful.

Even so, they say, they’d like to get much closer to Europa to see what’s going on.

“We performed diligent safety checks to remove possible contaminants in ground-based observations,” said Avi Mandell, a Goddard planetary scientist on Paganini’s team. “But, eventually, we’ll have to get closer to Europa to see what’s really going on.”

They’ll get their wish fairly soon. NASA’s Clipper mission is set to launch in 2025, with the objective of analyzing Europa’s habitability and chemistry, as well as its geology. The mission will also aid in the selection of a landing site for the future Europa Lander, which, as the name implies, is scheduled to land on Europa to analyze it in unprecedented detail. Even before that, the ESA’s JUpiter ICy moons Explorer (JUICE) is set to launch in 2022, with the purpose of analyzing Jupiter’s Galilean moons: Ganymede, Callisto, and Europa.

For a period, the two spacecraft will both be orbiting Europa, enabling us to understand the satellite better than ever before. Hopefully, these missions could help answer one of the most tormenting questions in modern astronomy.

Europa, this small frozen rock orbiting Jupiter, has water. Could it have life?

Image credits: NASA / JPL.

NASA mission to the moon Europa gets the green light

Artist’s view of the Europa Clipper spacecraft’s early (2016) design.
Image credits NASA.

NASA has confirmed that the Europa Clipper is entering its next phase. Now, researchers and engineers will complete the final design stage and move to the construction and testing of the entire spacecraft and science payload.

Backpacking through Europa

“We are all excited about the decision that moves the Europa Clipper mission one key step closer to unlocking the mysteries of this ocean world,” said Thomas Zurbuchen, associate administrator for the Science Mission Directorate at NASA Headquarters in Washington.

“We are building upon the scientific insights received from the flagship Galileo and Cassini spacecraft and working to advance our understanding of our cosmic origin, and even life elsewhere.”

The Europa Clipper mission will investigate Jupiter’s moon Europa, looking especially for signs of life. It will also give us the data to finally determine whether Europa is clad in a thick ice shell, or if it does indeed harbor liquid water beneath the surface.

Europa is no larger than Earth’s moon. However, its close proximity to Jupiter could heat up the moon’s interior and ocean (if it has one). As tides raised by Jupiter in Europa’s ocean rise and fall, they may cause cracking, additional heating and even venting of water vapor into the airless sky above Europa’s icy surface.

The mission will send a highly capable, radiation-tolerant spacecraft that will perform repeated close flybys of the icy moon from a long, looping orbit around Jupiter.

In order to develop this mission on a budget, NASA aims to have the Europa Clipper spacecraft complete and ready for launch as early as 2023. However, their baseline commitment places the launch readiness date sometime in 2025.

Table salt found on Jupiter’s satellite Europa, sparks debate about potential life

Europa’s subsurface oceans might be a lot more like the ones on Earth, raising a tantalizing question: could life exist in the satellite’s depths?

Jupiter’s icy moon Europa might have a salty ocean. Image credits: NASA.

When you think about Earth-like places in our solar system, Europa is probably not on the list. A frigid, ice-covered satellite, hanging around in Jupiter’s orbit does not exactly resemble what we see around us every day. However, the similarities between the Earth and Europe might lie beneath the surface — literally.

Researchers have known for quite a while that beneath its surface ice, Europa hosts oceans of liquid water. However, the chemistry of this water has remained rather unclear. A new study suggests that this ocean might be salty, just like the ones on Earth.

Using a visible light spectral analysis, planetary scientists at Caltech and the Jet Propulsion Laboratory found that the yellow color visible on portions of the surface of Europa is actually sodium chloride — a compound you might know as table salt.

A closer view of some of Europa’s surface. Image credits: NASA.

This doesn’t really come as a surprise since it was hypothesized for a while that the ocean might be salty, but it’s a heavy piece of evidence, suggesting that Europa’s oceans might be quite similar to Earth’s oceans.

Confirming the findings wasn’t easy, though.

“We thought that we might be seeing sodium chlorides, but they are essentially featureless in an infrared spectrum,” says Mike Brown, the Richard and Barbara Rosenberg Professor of Planetary Astronomy at Caltech and co-author of the Science Advances paper.

So what the team did was to irradiate ocean salts in a laboratory, mimicking the conditions on Europa. They found that several changes occur after irradiation — most importantly, the salts changed color to exactly what was seen on Europa in a region called the Tara Regio.

“Sodium chloride is a bit like invisible ink on Europa’s surface. Before irradiation, you can’t tell it’s there, but after irradiation, the color jumps right out at you,” says Hand, scientist at JPL and co-author of the Science Advances paper, adding that salt could also be a complicated chain of sub-surface processes and not come directly from the oceans.

“We’ve had the capacity to do this analysis with the Hubble Space Telescope for the past 20 years,” Brown says. “It’s just that nobody thought to look.”

The consequences of this discovery are not trivial. Life as we know it requires three things: water, energy, and suitable chemistry. Salt, specifically the sodium ions in table salt, is also crucial for a whole range of metabolic processes in plant and animal life. So the main ingredients for life may very well be on Europa. It’s still too early and speculative to say whether this is actually the case, but it certainly makes Europa one of the most interesting targets for future exploration.

The study was published in Science Advances.

Tunneling bot.

Nuclear-powered ‘tunnelbot’ could probe the depths of Europa’s oceans

Researchers at the University of Illinois at Chicago (UoI) have designed a nuclear-powered ‘tunnelbot’ to explore Europa, Jupiter’s ice-bound moon.

Tunneling bot.

Artist’s rendering of the Europa “tunnelbot.”
Image credits Alexander Pawlusik / LERCIP Internship Program, NASA Glenn Research Center.

Europa (the moon, not the continent) has captured the imaginations of space buffs around the world since 1995. That year saw NASA’s Galileo spacecraft’s first flyby around the moon which, along with subsequent investigations in 2003, pointed without a doubt to a liquid ocean beneath the icy surface.

All that water makes Europa a very strong candidate for alien microbial life or at least evidence of now-extinct microbial life. Needless to say, researchers were very thrilled about paying the moon a visit. However, we simply didn’t have any machine capable of pushing through the crust and then braving the oceans beneath — at least, not until now.

We all live in a nuclear submarine

“Estimates of the thickness of the ice shell range between 2 and 30 kilometers [1.2 and 18.6 miles], and is a major barrier any lander will have to overcome in order to access areas we think have a chance of holding biosignatures representative of life on Europa,” said Andrew Dombard, associate professor of earth and environmental sciences at the University of Illinois at Chicago.

Dombard and his spouse, D’Arcy Meyer-Dombard, associate professor of earth and environmental sciences at UoI, are part of the NASA Glenn Research COMPASS team, a multidisciplinary group of scientists and engineers tasked with designing technology and solutions for space exploration and science missions. Together with the team, Dombard presented their new design — a nuclear-powered tunnelling probe — at the American Geophysical Union meeting in Washington, D.C. this week.

The so-called “tunnelbot” is meant to pierce through Europa’s ice shell, reach the top of its oceans, and deploy instruments to analyze the environment and search for signs of life. The team didn’t worry about how the bot “would make it to Europa or get deployed into the ice,” Dombard said, instead focusing on “how it would work during descent to the ocean.”

Such a tunnelbot should be able to take ice samples as it passes through the moon’s shell, water samples at the ocean-ice interface, and it should be able to search the underside of this ice for microbial biofilms, the team explains. Finally, it should also be capable of searching for and investigating liquid water “lakes” within the ice shell.

Two designs were considered for the job: one version of the robot powered by a small nuclear reactor, and another powered by General Purpose Heat Source bricks (radioactive heat source modules designed for space missions). In both cases, heat generated by the power source would be used to melt through the ice shell. Communications would be handled by a string of “repeaters” connected to the bot by optic fibre cables.

NASA is very interested in visiting Europa, particularly because of its potential to harbor life. However, the bot designed by Dombard’s team isn’t an official ‘go’ sign for such an expedition. Whether NASA will plan tunneling, and if one of these designs would be selected for the job, remains to be seen.

Ice spikes on Europa could be threatening for future missions

Blades of ice rising from the surface of Europa, Jupiter’s frozen moon, will likely pose major hazards for future space missions aiming to land on the satellite.

Europa. Image credits: NOAA.

Water and ice

When it comes to space exploration, few things are as exciting as Europa. Sure, the Earth’s moon or Mars spark our imagination, but Europa is much more likely to host life — beneath its frozen surface.

Slightly smaller than Earth’s Moon, Europa is primarily made of silicate rock, but because it’s so far away from the Sun, its surface is completely frozen. Initially, astronomers didn’t give much attention to it, but the Galileo mission (launched in 1989) showed that there’s much more to Europa than meets the eye.

Current models now show that heat from tidal flexing causes the subsurface to stay liquid, enabling the Jovian moon to host an ocean of liquid water, right beneath its surface. Since liquid water is crucial for life as we know it, this makes Europa a prime candidate — and to make things even better, astronomers provided strong evidence of water plume activity on Europa, suggesting that the ocean is interacting with the seafloor, having tectonic-like activity. All of this makes Europa a prime candidate for searching extraterrestrial life.

But if we want to really see if there’s life on Europa, we need to send a lander mission there, and that’s not gonna be easy. A new paper published today in Nature Geoscience suggests that Europa’s jagged surface will make any landing mission even more difficult due to a phenomenon that’s also present on Earth: the so-called penitentes.

Penitentes

Penitentes in Aconcagua.

The penitentes were formally described by Charles Darwin in 1839: giant, blade-like ice features in the Andes mountains. When the weather is very dry and cold, the sun’s warm rays can cause parts of the ice and snow to undergo sublimation (turn from ice into vapour, without first becoming liquid).

“On Earth, the sublimation of massive ice deposits at equatorial latitudes under cold and dry conditions in the absence of any liquid melt leads to the formation of spiked and bladed textures eroded into the surface of the ice. These sublimation-sculpted blades are known as penitentes,” researchers write in the study.

A similar process has been observed on Pluto, for instance, so we know that it can happen on extraterrestrial bodies. Daniel Hobley of Cardiff University and his team investigated the conditions that could give rise to Penitentes on icy worlds such as Europa.

They found that conditions on Europa favour the development of penitentes, particularly at latitudes below 23°, which in turn, could threaten potential future missions.

“Although available images of Europa have insufficient resolution to detect surface roughness at the multi-metre scale, radar and thermal data are consistent with our interpretation. We suggest that penitentes could pose a hazard to a future lander on Europa,” the study concludes.

Both NASA and ESA have Europa flyby missions scheduled for the 2020s.

Life may be teeming just inches beneath Europa’s frozen surface

Life may be tantalizingly close to Europa’s surface — just deep enough to be hidden from us, but close enough that mere scratches could bring it to the surface.

Radiation from Jupiter can destroy molecules on Europa’s surface. Material from Europa’s ocean that ends up on the surface will be bombarded by radiation, possibly destroying any biosignatures, or chemical signs that could imply the presence of life. Credit: NASA/JPL-Caltech.

As far as alien life is concerned, Europa doesn’t seem like a particularly attractive place, at least at a first glance. Jupiter’s frozen moon seems like a small, barren world, too far away from the Sun to draw any interest. But modern science has found that beneath Europa’s frigid surface, there almost certainly lies an ocean of liquid water — an ocean of water believed to be in direct contact with the satellite’s core, which could lead to intriguing chemical reactions that favor the development of life. We already know from thermal vents on Earth that ecosystems can form without energy from the sun, relying on chemical and thermal energy from the depths of the ocean.

Could this also be the case on Europa?

Well, astronomers already suspect that plumes of water and gas could contain the biosignatures of life, but then again — so might the surface of Europa itself. In a new study addressing this issue, researchers explain that if these signatures exist, they may very well be close to the surface — they just need to survive the intense radiation pummeling from Jupiter, which can destroy or alter material transported up to the surface.

“Our results also show that amino acids, although heavily reduced in concentration, would persist at detectable levels … over 10 million year timescales at 10 centimeter depths even in the harshest radiation environments on the surface of Europa,” the researchers write in the paper, published today in Nature Astronomy.

Europa’s surface might host signs of life. Image credits: NASA.

They published a new comprehensive map detailing this radiation. As scientists are trying to see what the best places to search for life are, this type of map can be extremely useful for deciding where not to look. The lead author Tom Nordheim, research scientist at NASA’s Jet Propulsion Laboratory, Pasadena, California, explains that understanding how radiation acts on Europa is vital for this search for alien life.

“If we want to understand what’s going on at the surface of Europa and how that links to the ocean underneath, we need to understand the radiation,” Nordheim said. “When we examine materials that have come up from the subsurface, what are we looking at? Does this tell us what is in the ocean, or is this what happened to the materials after they have been radiated?”

Nordheim and colleagues found that radiation-surviving amino acids could hide as close as 10 cm beneath the surface — a mere scratch away — though in reduced concentrations. If they want to increase their odds of finding life, astronomers should go further from Europa’s equator, towards its higher latitudes — where the moon points away from Jupiter. Furthermore, they should look for “young” ice, no older than 10 million years.

Of course, this is all based on a huge hypothetical: the idea that life on Europa does exist — something which we have no information about and are only theorizing at the moment. But the study comes right in time, as both NASA and the ESA aim to send life-searching shuttles to Europa in the not-so-distant future: the early 2020s.

The so-called Europa Clipper mission from NASA will explore the habitability of Europa, and tell its sister mission, the Europa Lander, where to look for signs of life. Meanwhile, JUICE (JUpiter’s ICy moon Explorer) will perform detailed investigations on Ganymede — another Jovian moon similar to Europa — and will also carry out investigations of Europa.

These missions would both benefit from this radiation map.

“The radiation that bombards Europa’s  leaves a fingerprint,” said Kevin Hand, co-author of the new research and project scientist for the potential Europa Lander mission. “If we know what that fingerprint looks like, we can better understand the nature of any organics and possible biosignatures that might be detected with future missions, be they spacecraft that fly by or land on Europa.”

Journal Reference: T. A. Nordheim et al. Preservation of potential biosignatures in the shallow subsurface of Europa, Nature Astronomy (2018). DOI: 10.1038/s41550-018-0499-8

NASA shuttle finds evidence of water plumes on Europa — sparking more hopes signs of life

NASA’s Galileo shuttle has found evidence of water plumes on Jupiter’s Moon Europa, transporting material from the internal ocean out into space. This not only confirms that Europa has liquid water beneath its frozen surface, but opens up the possibility of sampling Europa’s water without needing to get down to the surface.

A graphic showing water emissions detected above Europa in Hubble Space Telescope observations from December 2012. Credit: NASA/ESA/L. Roth/SWRI/University of Cologne.

When people first considered the possibility of extraterrestrial life, the Moon or Venus seemed likely candidates. Then, as we understood that isn’t really the case, Mars became the main point of interest. But once again, rovers showed that life isn’t really thriving on Mars — though that might have been the case at some point in the past. Now, unlikely candidates have emerged: frigid satellites like Europa.

Researchers believe that beneath its frozen surface, Europa features an ocean of liquid water which may very well host life.

Europa is archetypical of the outer Solar System’s ‘ocean worlds’ — frozen satellites with liquid water hidden beneath a few kilometers of ice. Naturally, an ocean of warm, liquid water sounds like a great place for life to emerge and develop — but how do you study that? The most straightforward way would be to send a lander to places like Europa, drill through the ice, and take samples, but that’s problematic for numerous reasons.

First, it would be extremely costly and pose several technical difficulties. Not only do you need to somehow land on the rough and unforgiving ice, but you also need to drill several kilometers deep. Then, there’s also the risk of contamination, the problem of analyzing the results, and about a million things that could go wrong in the process. But there’s another way which might offer similar results: instead of digging down to the liquid water, what if the liquid water comes to us?

Telescope observations have indicated the existence of water plumes — columns of liquid water flowing to the surface, and even way above it. In 2012 and 2016, Hubble Space Telescope observed plume-like phenomena, but it’s still unclear if what Hubble saw was actually a plume, since the observation was made very close to the telescope’s maximum resolution.

Now, however, NASA has found much clearer evidence of these plumes, thanks to the Galileo spacecraft.

Galileo studied the planet Jupiter and its moons from 1989 to 2004. Looking through the data of a Europa flyby, Xianzhe Jia and colleagues spotted something unusual. During this flyby, which dropped below 400 km altitude, the shuttle’s magnetic instruments detected some unusual magnetic waves and plasma — which they interpreted as a plume.

Reconstructing Galileo’s path, they found that the magnetic anomaly coincides with a region of anomalous temperatures. This unusually hot area can only be fully explained by a transport of heat from Europa’s interior — something was carrying heat from Europa’s depths to the surface. In other words, all the evidence points towards a plume.

This finding could be extremely helpful for future missions to Europa, such as NASA’s Europa Clipper and ESA’s Jupiter Icy Moons Explorer spacecraft, which are scheduled to arrive in Jupiter’s system in the 2020s and 2030s respectively. Being able to study surface water or even better, plumes high up in the atmosphere would make a big difference for these missions.

It’s also not just Europa — Saturn’s moons Enceladus and Titan are also top priorities for extraterrestrial life in our solar system, and they’re also frozen moons with a subsurface ocean of liquid water. We certainly live in exciting times.

Journal Reference: “Xianzhe Jia et al. Evidence of a plume on Europa from Galileo magnetic and plasma wave signatures,” Nature Astronomy. DOI 10.1038/s41550-018-0450-z.

Salty, subglacial lakes in Canada could be key for studying aliens

A sealed lake is an ideal place to look for clues about extraterrestrial life — and researchers have just identified a few more.

Small valley glacier exiting the Devon Island Ice Cap in Canada. The Devon Ice Cap appears to be the only holder of salty subglacial lakes (as far as we know). Image credits: NASA Goddard Space Flight Center.

Life on other planets might not be located the most obvious of places. While researchers used to think that Earth-like planets such as Mars or Venus were capable of holding life, modern research has shown that places like Europa or Enceladus are much more likely to be hospitable (Europa and Enceladus are two frozen moons of Jupiter and Saturn respectively). However, astronomers have evidence that beneath the frozen surface lies a vast ocean of liquid where life may very well thrive. Researchers want to explore this avenue before actually landing a shuttle on the surface of these moons (which may take a very long time) and the best way to do that is by studying subglacial lakes.

Subglacial lakes are bodies of water perfectly sealed under a glacier — typically an ice cap or ice sheet. There are 400 known subglacial lakes in the world, most of which can be found in Antarctica, with Lake Vostok being probably the most well known. Since they’re sealed off from the rest of the world, life can develop and adapt independently — this essentially means that subglacial lakes are potentially unique microbial habitats which can provide information about how life might have developed on places like Europa. Now, lead author Anja Rutishauser, a Ph.D. student at the University of Alberta, has found the first subglacial lakes in the Canadian High Arctic.

“If there is microbial life in these lakes, it has likely been under the ice for at least 120,000 years, so it likely evolved in isolation,” Rutishauser said. “If we can collect a sample of the water, we may determine whether microbial life exists, how it evolved, and how it continues to live in this cold environment with no connection to the atmosphere.”

An artist’s cross-section of Lake Vostok, the largest known subglacial lake in Antarctica. Importantly, the lake is sealed by kilometers of ice. Image credits: Nicolle Rager-Fuller / NSF.

What makes these newly discovered lakes extra special is that they seem to contain very salty water — all other subglacial lakes we know of are thought to contain freshwater, or only mildly saline water. All subglacial lakes are good analogs for life beyond Earth, but the hypersaline nature of these newly discovered lakes makes them particularly tantalizing analogs for ice-covered moons in our solar system, according to the researchers. There is strong evidence that Jupiter’s icy moon Europa contains hypersaline water.

The lake was discovered using remote sensing, which is promising, especially considering that NASA’s Europa Clipper mission, which is set to launch sometime in the 2020s and take samples from Europa, will use similar remote sensing techniques. An analysis of the radar data shows that the lakes are located 550 to 750 meters beneath the Devon Ice Cap, one of the largest ice caps in the Canadian Arctic. They’ve not had contact with the outside world for tens of thousands of years.

“If there is microbial life in these lakes, it has likely been under the ice for at least 120,000 years, so it likely evolved in isolation,” Rutishauser said. “If we can collect a sample of the water, we may determine whether microbial life exists, how it evolved, and how it continues to live in this cold environment with no connection to the atmosphere.”

Now, researchers would like to sample this environment, which is probably more complicated than you’d expect. It’s not just drilling through hundreds of meters (or perhaps even kilometers) of ice that’s problematic: there’s also the matter of contamination — if a unique microbial environment does exist, the last thing you’d want to do is contaminate it.

Journal Reference: Anja Rutishause et al. Discovery of a hypersaline subglacial lake complex beneath Devon Ice Cap, Canadian ArcticDOI: 10.1126/sciadv.aar4353

Europa TectPun.

Europa’s tectonics might be powered by salt, could sustain life on the moon

New research suggests that Europa’s icy shell may exhibit tectonic systems similar to those on Earth. This would have major implications for live developing on the moon.

Europa TectPun.

Image credits Alex Micu / ZME Science; free to use with attribution.

A team of Brown University researchers used computer modeling to show that subduction — the “sinking” of tectonic plates — is physically possible on Jupiter’s freezing moon, Europa. The result support earlier work that identified regions on the moon’s ice shell which seem to be expanding in a fashion similar to what we see down here on Earth. Overall, the study fleshes our understanding of tectonic processes in general, those on Europa in particular, and raises some very exciting possibilities regarding life in its undersurface waters.

Tectonics on the rocks

“What we show is that under reasonable assumptions for conditions on Europa, subduction could be happening there as well, which is really exciting,” says Brandon Johnson, assistant professor in Brown’s Department of Earth, Environmental and Planetary Sciences and a lead author of the study.

We’ve found several different types of tectonic systems in the solar system, from Venus’ hickey-like coronae to Mercury’s contraction-powered tectonics. Back down on our own plastic-laden corner of the Universe, subduction is powered chiefly by differences in temperature. The crust, Earth’s outer layer, is formed of plates floating on top of the mantle (an ocean of fluid, molten rock). Being solid and cold, these plates are denser than the material in the mantle — this bulk provides the negative buoyancy that pulls crustal slabs into the mantle.

A few years ago, Europa was also shown to maintain its own tectonic processes. Despite having an icy, rather than rocky, crust, there was evidence that processes very similar to Earth’s subduction were going on. But we didn’t have any idea why. We have reason to believe that the moon’s interior is kept warm by the gravitational tug of its massive host, Jupiter. This means that Europa’s ice shell is made up of two layers, Johnson says — a thin outer cover of very cold ice sitting atop a slightly warmer, convecting layer. So the working hypothesis was that surface slabs would break off and sink through the mushy ice below.

Europa poster.

The layers of Europa.
Image credits Kelvinsong / Wikimedia.

There is one major hiccup with that hypothesis, however: as the slabs pushed down into the warmer ice below, they would quickly warm to match its temperature. When that happened, the slab would have the same density of the surrounding ice — so they wouldn’t sink.

Johnson and his team developed a subduction model that could be maintained across Europa regardless of these temperature differences. What they used is salt. A difference in salinity between the two ice layers would provide the density gap needed for a slab to subduct.

“Adding salt to an ice slab would be like adding little weights to it because salt is denser than ice,” he explains. “So rather than temperature, we show that differences in the salt content of the ice could enable subduction to happen on Europa.”

Evidence in support of a salinity difference in Europa’s layers come from the moon’s occasional water upwellings — a process similar to magma upwellings here on Earth. Such events leave behind salty traces on the crust.

Sink 4 life

Plumes Europa.

Composite image shows a suspected plume of material erupting two years apart from the same location on Europa.
Image credits NASA/ESA/W. Sparks (STScI)/USGS Astrogeology Science Center.

The results help patch up our understanding of Europa’s tectonics and help us get a better understanding of how Earth’s tectonic processes work. It also bolsters the case for a habitable(-ish, at least) ocean on the moon by pointing to an undersurface ocean that’s dynamic enough to sustain tectonics.

Perhaps most excitedly, it teases with the possibility of organisms eeking out a living below the frozen surface.

“If indeed there’s life in that ocean, subduction offers a way to supply the nutrients it would need,” Johnson adds.

So what do tectonic processes have to do with life? Well, life (as we understand it) needs a lot of different building blocks including hydrogen, oxygen, nitrogen, phosphorous, and sulfur. These are usually found in ample supply in planets, but they’re not evenly spread around. Even worse, life consumes these basic nutrients wherever it happens to pop up.

Tectonics brings a lot of matter motility to the scene. By churning everything while sinking and moving about, tectonic plates make sure elements are recirculated vertically throughout a planetary system, ensuring there’s always something tasty for organisms to munch on when new plates form.

It’s by no means a “there’s life on Europa, you guys” find, but some important conditions are there. Which makes NASA’s upcoming mission to Europa just that much more exciting.

The paper “Porosity and salt content determine if subduction can occur in Europa’s ice shell” has been published in the Journal of Geophysical Research: Planets.

Cassini spacecraft diving through the plume of Saturn's moon Enceladu

All the ingredients for alien life: NASA finds hydrogen spewing out of Saturn’s icy moon, likely propelled from hydro-thermal vents

NASA’s Cassini spacecraft has found hydrogen molecules in the plumes spewing off one of Saturn’s icy moons called Enceladus. This suggests that there are hot spots hidden beneath the ocean which can provide enough energy for life to both appear and thrive, given how common hydrothermal vents or underwater geysers are on Earth’s ocean floor. Additionally, a potential plume was identified gushing out of Europa, one of Jupiter’s moon, which suggests similar processes to Enceladus might occur beneath the moon’s crust of ice as well.

Cassini spacecraft diving through the plume of Saturn's moon Enceladu

NASA’s Cassini spacecraft diving through the plume of Saturn’s moon Enceladus, in 2015. Credit: NASA/JPL.

“This is the closest we’ve come, so far, to identifying a place with some of the ingredients needed for a habitable environment,” said Thomas Zurbuchen, associate administrator for NASA’s Science Mission Directrate at Headquarters in Washington. ”These results demonstrate the interconnected nature of NASA’s science missions that are getting us closer to answering whether we are indeed alone or not.”

All the ingredients for life

Around these hydrothermal vents on Earth, cold water mingles with hot magma to produce hydrogen gas that rises from the vents and the same chemical processes provide ample breeding grounds for microbial life to thrive. Similarly, Enceladus’ hydrothermal vents could provide similar conditions with hydrogen acting as a major food source and the heat providing the right temperature. The energy content of the hydrogen sniffed by Cassini is equivalent to 400 pizzas, said on NASA researcher at the press conference.

“Although we can’t detect life, we’ve found that there’s a food source there for it. It would be like a candy store for microbes,” said Hunter Waite, lead author of the Cassini study.

The discovery was published in the journal Science was made by NASA’s Cassini mission, right on time since the spacecraft is nearing the end of its mission and will soon be decommissioned. The spacecraft ‘sniffed’ the hydrogen as it gushed out of Enceladus’ four parallel depressions known as ‘tiger stripes’ on Oct. 28, 2015. The plumes get ejected as high as 50 to 100 km above the moon’s surface, despite the fact we’re talking about a cosmic body that’s comparable in size with our very own Moon. This means whatever’s propelling the plumes is an insanely energetic process. Scientists determined that nearly 98 percent of the gas in the plume is water, about 1 percent is hydrogen and the rest is a mixture of other molecules including carbon dioxide, methane, and ammonia.

cassini-enceladus

How Cassini scientists think water interacts with rocks at the bottom of the ocean of Saturn’s icy moon Enceladus, producing hydrogen gas. Credits: NASA/JPL-Caltech

Data suggests that the Enceladus ocean contains up to 1.4% hydrogen and 0.8% carbon dioxide, besides methane, propane, acetylene, formaldehyde, and ammonia — all of which were detected previously.

Scientists had suspected for a long time that intense energetic processes happen on Enceladus given the moon has a solid, hot core whose heat is capable of sustaining a 10-kilometer thick liquid ocean beneath the icy surface. Previous observations suggest the core is also porous allowing pockets of the ocean to heat up more than others.

“Confirmation that the chemical energy for life exists within the ocean of a small moon of Saturn is an important milestone in our search for habitable worlds beyond Earth,” said Linda Spilker, Cassini project scientist at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California.

Another paper published by researchers working with the Hubble Space Telescope reported plume erupting from Europa, the smallest of the four Galilean moons orbiting Jupiter. The plume was seen gushing from the same location an earlier event occurred in 2014. These findings suggest that plumes on Europa might be a real phenomenon.

The plume rose to about 100 kilometers above Europa’s surface from an unusually warm region where cracks dot the moon’s icy crust. Like on Enceladus, this may be evidence of hot water erupting from the moon’s interior.

“The plumes on Enceladus are associated with hotter regions, so after Hubble imaged this new plume-like feature on Europa, we looked at that location on the Galileo thermal map. We discovered that Europa’s plume candidate is sitting right on the thermal anomaly,” said William Sparks of the Space Telescope Science Institute in Baltimore, Maryland. Sparks led the Hubble plume studies in both 2014 and 2016.

https://www.youtube.com/watch?v=wG-jrJnfI3g

All of these findings are terribly exciting. They tell us that both of these ‘ocean worlds’ are potentially inhabitable. What’s certain is that we need to do more work and keep our eyes open for more evidence of life on these seemingly inhospitable worlds — and we might get a confirmation sooner than some think. In the 2020s, NASA’s Europa Clipper mission will be ready to make similar measurements to Hubble’s, but from thousands of times closer. As for Enceladus, NASA is already talking about landing a lander on one of the moon’s tiger stripes where it should literally start drilling for life. The stars seem to be aligning.

“If there are plumes on Europa, as we now strongly suspect, with the Europa Clipper we will be ready for them,” said Jim Green, Director of Planetary Science, at NASA Headquarters.

NASA’s mission to search for life on Europa takes shape

NASA just revealed comprehensive plans to search for life on Europa. The space agency intends to send a stationary lander which will include three different instrument suites which will collect samples and analyze them, looking for native life forms.

Artist’s illustration of NASA’s possible Europa lander on the surface of the icy Jovian moon.
Credit: NASA/JPL-Caltech

If we want to look for extraterrestrial life, Europa might be one of the best guesses in the solar system. An icy satellite doesn’t seem like a likely candidate, but astronomers are fairly certain it is. After finding convincing evidence of water plumes on Jupiter’s moon, it seems quite likely that Europa has Earth-like oceans beneath its frozen surface. These oceans might very well foster life, which is why NASA is quite eager to send a probe onto its surface.

While the lander mission still hasn’t been detailed yet, Congress wants it to happen — so NASA will likely make it happen. The report is also preliminary, which means that many things from it might still change, but it’s a clear show of intent: if everything goes according to plan, we’ll be soon searching for Europa’s life forms.

Viking, Mars, and Europa

Mars was a prime candidate for extraterrestrial life, and there may well be life on Mars, but we’ve learned quite a few things in the past decades. The Viking landers searched for life on Mars in the 1970s, sending back results that are still debated to this day. Two instruments failed to send conclusive evidence, but one did provide some tantalizing information, indicating the presence of organic molecules. But if there’s one thing we learned from the Viking missions, is that you can’t just bump in and out and hope to sort things out.

“What Viking taught is us that you don’t just jump in and look for life,” says Curt Niebur, program scientist on the Europa lander mission, as well as the Europa Clipper, which will fly by the frozen moon in the 2020s. “You need a general understanding of the environment in which you’re looking, because it can complicate things.”

This close-up of Europa, taken by the Galileo spacecraft in 1997, has been color-enhanced to reveal surface features. Blue-white terrain shows relatively pure water ice; reddish stripes may contain salts from an ocean, and hence would be a good target location for a lander. Credit: NASA/JPL-Caltech/SETI Institute

Things get even trickier on Europa. There’s very little chance that life survives on its surface, so you need to touch down and take samples from beneath the surface. Thus, NASA wants to equip three instrument suites, featuring an “organic compositional analyzer,” a microscope system and a “vibrational spectrometer.” The research suite is tailor made to identify extremophiles — microscopic creatures which survive in extreme environments.

“The science return possible from the model payload is such that, if life is present in Europa’s ice at a level comparable to one of the most extreme and desolate of environments on Earth (Lake Vostok ice), then this mission could detect life in Europa’s icy surface,” the report’s authors wrote. (Lake Vostok lies beneath the surface of the East Antarctic Ice Sheet.)

Aside from looking for life, the mission would also characterize Europa’s surface and its subsurface habitability. Even if it isn’t inhabited, it could be habitable. Who knows, at some point in the future, Europa might become Earth’s fishery.

NASA finds more evidence of water plumes on Europa

Astronomers working with NASA’s Hubble Telescope have confirmed what many researchers were already suspecting: water plumes are erupting from Jupiter’s moon Europa. This means that we could sample the water on the satellite without having to drill into it.

This composite image shows suspected plumes of water vapor erupting at the 7 o’clock position off the limb of Jupiter’s moon Europa. Credits: NASA/ESA/W. Sparks (STScI)/USGS Astrogeology Science Center

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 definitely a likely candidate. We’ve written extensively before about the life harboring possibilities of 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, but acquiring valuable samples would be very difficult because we’d have to drill through a lot of ice. Thankfully, we might get a bit of help from the local geology – basically, we could just send a shuttle there and the water might come to it.

“Europa’s ocean is considered to be one of the most promising places that could potentially harbor life in the solar system,” said Geoff Yoder, acting associate administrator for NASA’s Science Mission Directorate in Washington. “These plumes, if they do indeed exist, may provide another way to sample Europa’s subsurface.”

Europa’s subsurface oceans have twice as much water than Earth’s, so there’s plenty of material to be ejected – the watery plumes are estimated to rise to about 125 miles (200 kilometers). The team, led by William Sparks of the Space Telescope Science Institute (STScI) in Baltimore observed these ejections while studying Europa’s atmosphere.

“The atmosphere of an extrasolar planet blocks some of the starlight that is behind it,” Sparks explained. “If there is a thin atmosphere around Europa, it has the potential to block some of the light of Jupiter, and we could see it as a silhouette. And so we were looking for absorption features around the limb of Europa as it transited the smooth face of Jupiter.”

[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 a more robust exploration is needed.[/panel]
During observations which lasted 15 months, the team noticed plume-like features three times. This confirms a previous study conducted by Lorenz Roth of the Southwest Research Institute in San Antonio, which detected vapor erupting from the frigid south polar region of Europa. They both used the same equipment but used a different method to reach the same conclusion.

“When we calculate in a completely different way the amount of material that would be needed to create these absorption features, it’s pretty similar to what Roth and his team found,” Sparks said. “The estimates for the mass are similar, the estimates for the height of the plumes are similar. The latitude of two of the plume candidates we see corresponds to their earlier work.”

However, even if these plumes are real, there’s no evidence that they are connected to the subsurface ocean. Europa’s surface is riddled with geological features, cracks and fissures, which could host liquid pockets of water – the plumes could originate there.

Both NASA and the European Space Agency are planning missions to Europa, and many astronomers are eagerly supporting a thorough exploration of the satellite. There is already a NASA spacecraft at Jupiter called Juno, which may provide more information about these plumes, but is not designed for this purpose.

“We took great pains to make sure that that spacecraft does not get anywhere near Europa, because we want to protect Europa from contamination,” says Curt Niebur, NASA’s program scientist for outer planets missions.

The work by Sparks and his colleagues will be published in the Sept. 29 issue of the Astrophysical Journal.

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.

NASA presents toolkit to search for life on Jupiter’s Moon Europa

Sending a probe to look for alien life is just half of the work – it’s the tools you send there that will actually do the job, and NASA has decided which tools it wants to send to Jupiter’s moon Europa, a place considered by many the likeliest to hold alien life.

Realistic-color Galileo mosaic of Europa, highlighting the mysterious lines. Image via Wikipedia.

Hundreds of years ago, many people were convinced that the Moon was inhabited by aliens. Even decades ago, some still had the belief that Venus might be inhabited, and up until very recently, Mars was considered the likeliest place in the solar system to hold alien life. We now know a lot about Mars, and while Martian life is still an open possibility, there are other, seemingly unlikely places, where astronomers hope to find life. Such is Jupiter’s Europa.

Water on Europa

Europa is one of Jupiter’s many moons, orbiting the gas giant in just over three and a half days. Naturally, when it’s so far away from the Sun, its surface is frozen. So why then do researchers have such great expectations? The first clues about Europa’s potential came when astronomers realized that it is extremely smooth. It’s so smooth that it seems there’s a liquid ocean beneath the frozen surface, one which might have the potential to host life.

But how could it have liquid water? The key is something called tidal flexing – basically, Jupiter is so massive that it tugs and pulls Europa, creating heat through friction and maintaining liquid water under a frozen crust, while also driving geological activity similar to plate tectonics. There were also other, more direct indications, such as in 2013, when astronomers spotted 200 km high water plumes spurting from its surface. Also in 2013, astronomers “tasted” the surface of Europa and found evidences of salt, something which was confirmed in May 2015. This suggests that the ocean is in interaction with the seafloor, which holds even more promise for life existing in the liquid water.

In December 2013, NASA reported the detection of “clay-like minerals” (specifically, phyllosilicates), often associated with “organic material” on the icy crust of Europa. But Europa’s most striking feature is a series of dark streaks crisscrossing the entire globe, called lineae (which is just “lines” in English). These lines are more than 20 km (12 mi) across, often with dark, diffuse outer edges, regular striations, and a central band of lighter material. But what could have caused them? While there are a few competing theories, it seems that they are “scars” from warm water erupting through the surface – again, an indication of liquid water.

Artist’s drawing of Europa. Image via Slate.

All in all, Europa is an intriguing place, and despite its appearance, it may very well harbor life beneath its frozen surface – hence why NASA is so keen to explore it and see if this is the case.

NASA’s mission to Europa

NASA has been planning a mission to Jupiter’s satellite for quite a while, but things seem to be finally coming together.

“We’re excited about the potential of this new mission and these instruments to unravel the mysteries of Europa in our quest to find evidence of life beyond Earth,” said John Grunsfeld, associate administrator for Nasa’s Science Mission Directorate.

The mission will come at a $30 million price tag, which honestly doesn’t seem that crazy when you consider that the objective is to send a probe 628.300.000 km away to study a frozen moon and look for alien life beneath its surface. To me, the very fact that we can actually do this is remarkable. The fact that we can do it at a lower price than a Eurocopter Tiger is even more exciting.

But as I said above, it’s not just about sending the probe there, there’s also the rather complicated issue of choosing what instruments you send on the mission. NASA received 33 proposals from universities and research institutions across the country for the mission’s science instruments; from these, they chose nine, which we present below:

  • Plasma Instrument for Magnetic Sounding (PIMS). This instrument is key for determining the location, thickness and salinity of Europa’s under-ice ocean. It works in conjunction with a magnetometer (next line)
  • Interior Characterization of Europa using Magnetometry (ICEMAG). Working together with PIMS, this magnetometer will measure the magnetic field near Europa and use multi-frequency electromagnetic sounding to help determine the parameters of Europa’s ocean.
  • Mapping Imaging Spectrometer for Europa (MISE). It will identify and map the distribution of organics, salts, acid hydrates, water ice phases, and other materials, to help determine the habitability of the ocean.
  • Europa Imaging System (EIS). This is basically a wide and narrow angle camera that will map most of Europa at 50 meter (164 foot) resolution, and will provide high resolution images of Europa’s surface.
  • Radar for Europa Assessment and Sounding: Ocean to Near-surface (REASON). This dual-frequency ice penetrating radar instrument is designed to characterize and sound Europa’s icy crust from the near-surface to the ocean, revealing its internal structure.
  • Europa Thermal Emission Imaging System (E-THEMIS). This is a “heat detector” that will highlight Europa’s active areas, specifically hotter vents and potential plumes.
  • MAss SPectrometer for Planetary EXploration/Europa (MASPEX). This instrument will determine the composition of the surface and subsurface ocean by measuring Europa’s think atmosphere and any material that might be ejected into it.
  • Ultraviolet Spectrograph/Europa (UVS). The main focus of UVS will be to spot out any water plumes spurting out – even smaller ones.
  • SUrface Dust Mass Analyzer (SUDA). The name pretty much says it all – SUDA will measure the composition of small, solid particles (dust) ejected from Europa.

Aside from the tools above, the SPace Environmental and Composition Investigation near the Europan Surface (SPECIES) instrument has been chosen for further technology development. This is a trove of instruments, a myriad of tools to help scientists figure out whether or not Europa might host life.

“This payload will help us answer all of these questions,” said Niebur, “and take great strides forward in understanding the habitability of Europa.”

However, astronomers stress that while these instruments can detect indicators of life, they are not directly life detectors.

NASA Plans Life-Searching Mission on Jupiter’s Satellite Europa

Jupiter’s satellite Europa is definitely one of the most interesting places in our solar system – despite being really far from the Sun and frozen on the surface, NASA researchers actually believe it is the best bet to search for extraterrestrial life. Now, scientists and engineers have actually planned a mission aimed to reveal whether life on Europa exists or not.

“Europa is clearly such a prime target for astrobiology that having a workshop like this to try and figure out all the ways in which we could possibly sample its ocean … [is] critically important,” said Kevin Hand, an astrobiologist at California’s Jet Propulsion Laboratory, who was at the meeting.

Several reports concluded that the icy moon might harbor life. Despite being extremely far from the Sun and therefore frozen on the surface, there is significant evidence that under the ice, there is actually an ocean of liquid water. Europa is thought to have a hot, iron core and an ocean underneath its thick crust of ice on the surface. Measurements indicate that the ocean is in liquid form and is actually warm, heated by the tidal stresses exerted on Europa by Jupiter and several other large moons, 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.

Scientists have decided on a mission called Clipper. The Europa Clipper is a concept still under development, but it will cost an estimated $2.1 billion and could launch as early as 2022. The plan is for the shuttle to brush by Europa about four dozen times over three and a half years, snapping photos and taking a good, close look at the moon.

“We are going to do a Europa mission, and I’m very excited about that,” said John Grunsfeld, a former astronaut who is now NASA’s associate administrator for the science mission directorate. “I think it’s unlikely that Congress is going tell us, ‘No, NASA shouldn’t be doing a Europa mission.’ Very unlikely.”

Still, just flying by isn’t going to help us learn whether or not life exists on Europa. There are a number of ideas floating around – the craziest one being blasting a piece of the satellite and measuring what flies out of it. A more tame (and likely) approach is to land a probe and have it look in the ice for life signatures, while the ideal version would involve also launching a submarine to dive in the under-ice waters.

But there are also serious hurdles – it will be a huge scientific and engineering task and will come with a hefty price tag. There is also the problem of contamination – if life does exist on Europa, then we might contaminate it with microorganisms brought from Earth. So an idea that popped up in this meeting is to have a probe orbit the satellite at close range and simply test the plumes of water vapor that erupt from the moon’s surface into space. In 2013, astronomers observed 200 km high plumes spurting from Europa’s surface. This would allow researchers to test the water without actually landing on Europa. However, the problem here is that these plumes can be very unpredictable and likely only erupt sporadically.

Artistic representation of water plums spurting out of Europa. Image via Daily Galaxy.

Artistic representation of water plums spurting out of Europa. Image credits: K. Retherford/Southwest Research Institute

“The plumes, if they exist, offer an incredible opportunity to go in and measure something and even search for life itself,” said Scott Bolton of the Southwest Research Institute, in San Antonio. “We don’t want to design an entire mission that’s based on that because they’re hard to see … but we do need to take advantage of this.”

So the desired method of test hasn’t been decided yet, but in the end, variety will probably be the better option – different types of data are better than any approach alone.

“The data we take from these spacecraft will last forever. And we’re not going to get a lot of opportunities to do these kinds of things,” says planetary scientist Sarah Hörst of Johns Hopkins University, in Baltimore. In the future, she says, when we might have a better idea of how to detect alien life, we will want to have enough data to mine for those extraterrestrial signatures.

As for what we should be looking for… this again is an open question; we have to be prepared for anything. Europan life may or may not exist, it might be microscopic or macroscopic (though the former seems more likely), and its chemistry might be different from anything we know.

“We need to go look for complexity,” said Lee Cronin of the University of Glasgow. Complex molecules—those with branches and different types of atoms—are usually clues that some kind of living factory is churning away nearby, he said.

Jupiter’s Moon Europa found to have Plate Tectonics

Europa, Jupiter’s icy moon is the only body in the Solar System found to have plate tectonics (besides Earth). A new study has found several defining features, including plate subduction, broken linear features and offset likely caused by strike slip faults.

Europa. Image via Wiki Commons.

An introduction to plate tectonics

Plate tectonics is one of the newest big theories in science. Developed in the 1960s, it claims that lithosphere, which is the rigid outermost shell of a planet (on Earth, the crust and upper mantle), is broken up into tectonic plates. These plates are not immobile – they move, especially because the Earth’s lithosphere has greater strength than the underlying asthenosphere. Lateral density variations in the mantle result in convection. Here on Earth, that movement is at a few cm per year.

plate tectonics earth

Plate tectonics movement. Image via BBC.

The exact mechanism of movement is still a matter of debate (with underlying magma currents being a newer proposal). Other major factors play a role, the most notable being the motion of the seafloor away from the spreading ridge (due to variations in topography and density of the crust, which result in differences in gravitational forces) and drag, with downward suction, at the subduction zones. Another explanation lies in the different forces generated by the rotation of the globe and the tidal forces of the Sun and Moon. It’s likely that all these forces (and probably others) work together to create the extremely complex movement we observe today.

So far, no other celestial body has been observed to have plate tectonics (other than Earth that is) – it’s the first time we can almost definitely say that we’ve found tectonic movement on an extraterrestrial body – and Jupiter’s moon was quite an unlikely candidate.

Europa’s plate tectonics

europa tectonics

Proposed structure of Europa. Image via NASA.

Up to 50 years ago, Europa held little interest for astronomers and geologists, but now, it is one of the most interesting bodies in the solar system. We regard it today as one of the places most likely to harbor life, and NASA is currently planning a mission to study it more carefully. So what changed?

Well, Europa is a moon of Jupiter primarily made of silicate rock and probably has an iron core. It has a tenuous atmosphere composed primarily of oxygen. However, it is covered with extremely smooth ice – but that doesn’t mean it can’t host life; on the contrary!

Scientists believe that under the frozen surface, there lies a vast ocean of liquid water. Europa is under a constant state of tug and pull from its planet, and this gravitational war causes friction. The friction generates heat, which is why we believe that there is liquid water beneath the ice. To make things even more interesting, huge 200 km water plumes were observed spurting from Europa. On December 11, 2013, NASA reported the detection of “clay-like minerals” (specifically, phyllosilicates), often associated with organic materials, on the icy crust of Europa. For all its low temperatures and icy features – the moon is an extremely interesting place; and it just got more interesting!

Europa’s lineae, colorized. Image via NASA.

Dr. Simon Katterhorn, geologist and former professor at the University of Idaho and Louise Prockter, planetary scientist at the Johns Hopkins Applied Physics Laboratory in Laurel, Maryland have discovered clear signs of plate tectonics on Europa. They studied lineae – dark streaks that cover the entire moon, caused by Jupiter’s gravitational attraction. They observed that some of these features appear to be moved – shifted, like in a strike slip fault. Other features appear to be abruptly ending, as if they were subducting under something else. The disappearance of material is entirely consistent with subduction, and when you also take into consideration the huge water plumes, it makes even more sense.

It’s pretty clear that we need a probe to better study this celestial body, and figure out its geological (and perhaps biological) secrets.

Journal Reference: Simon A. Kattenhorn& Louise M. Prockter. Evidence for subduction in the ice shell of EuropaNature Geoscience (2014) doi:10.1038/ngeo2245

Pluto’s Moon may have harbored underground ocean

The new NASA-funded study showed that if the icy surface of Pluto’s giant moon Charon is cracked, analyzing the fractures could show if the interior was warm and perhaps warm enough to have maintained a subterranean ocean of liquid water.

Pluto is the most distant planetoid (no longer a planet, sorry) in the solar system. It’s extremely far from us, as it orbits the sun over 29 times faster than the Earth. The surface temperature estimated is approximately 380 degrees below zero Fahrenheit (around minus 229 degrees Celsius), which means it is way too cold to allow liquid water on its surface. Pluto’s moons are no less frigid than the planet they orbit around. Since until further investigation it is highly difficult to draw any conclusions, in July 2015 NASA’s New Horizons spacecraft will be the first to visit Pluto and Charon, and a much more detailed observation will be provided to the scientists.

‘Our model predicts different fracture patterns on the surface of Charon depending on the thickness of its surface ice, the structure of the moon’s interior and how easily it deforms, an how its orbit evolved. By comparing the actual New Horizons observations of Charon to the various predictions, we can see what fits best and discover if Charon could have had a subsurface ocean in its past, driven by high eccentricity,’ declared Alyssa Rhoden of NASA’s Goddard Space Flight Center in Greenbelt, Maryland, who is lead author of a paper on this research.

There are some moons around the gas giant planets in the outer solar system that have cracked surfaces with evidence for ocean interiors – Jupiter’s moon Europa and Saturn’s moon Enceladus are just two examples of this kind. Concerning Charon, the study finds that a past high eccentricity could have been the cause for high tides, causing friction and surface fractures.

Compared to Pluto, this moon is suspiciously massive, about one-eighth of its mass, an undoubted solar system record. And it’s thought to have formed even much closer to Pluto, as a result of a giant impact ejecting material off the planet’s surface. The material went, thus, into orbit around Pluto and coalesced under its own gravity to form Charon, along with other smaller moons.

The gravity between Pluto and Charon caused their surfaces to bulge toward each other, so there were strong tides on both worlds at the beginning. The friction resulting from this is believed to have caused the tides to slightly lag behind their orbit positions. The lag is believed to act like a brake on Pluto, which causes its rotation to slow while transferring the rotational energy to Charon. This, at its turn, makes the moon speed up and move farther away from Pluto.

Depending on exactly how Charon’s orbit evolved, particularly if we went through a high-eccentricity phase, there may have been enough heat from tidal deformation to maintain liquid water beneath the surface of Charon for some time. Using plausible interior structure models that include an ocean, we found that it wouldn’t have taken much eccentricity to generate surface fractures like we are seeing on Europa’, declared Roden.

According exclusively to the observations by telescopes, Charon’s orbit is in a stable end state – a circular orbit with the rotation of both Pluto and Charon slowed to the point where they always show the same side to each other. It’s this orbit that’s expected to generate significant tides, so there’s the possibility for any ancient underground ocean to be frozen, according to the scientist.

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Considering the fact that liquid water is believed to be essential in order to detect any known forms of life, the oceans in Europa and Enceladus are believed to be the places where there’s the possibility to found extraterrestrial life. However, a usable energy source is also required to maintain life, along with many key elements (among which carbon, nitrogen, phosphorus). Since there is no knowledge of the oceans harboring these additional ingredients, or if they existed for a period of time enough for life to form, the same questions apply to any other ancient ocean that may have existed beneath the icy crust of Charon.

The research was founded by the NASA Postdoctoral Program at the NASA Goddard Space Flight Center, which is administrated by Oak Ridge Associated Universities, and NASA Headquarters through the Science Innovation Fund.

Astronomers find 200 km high water plums spurting from Europa

Europa, Jupiter’s satellite, has emerged as one of the top locations in the Solar System in terms of its potential of hosting extraterrestrial life. Despite the fact that it lies so far from the Sun, scientists believe that a liquid ocean lies under its icy surface – and that ocean could very well host life.

K. Retherford/Southwest Research Institute
The plumes detected on Europa by the Hubble Space Telescope may be 200 kilometres tall, as depicted in this artist’s impression.

Now, Europa just got a lot more interesting for that purpose: astronomers spotted possible plumes of water spraying from its South Pole.

The jets resemble an icy geyser, very similar to those already observed on Saturn’s moon Enceladus. However, plumes on Enceladus are even more interesting because they have such a good chance of tapping into a watery environment that hosts life.

“If this pans out, it’s potentially the biggest news in the outer Solar System since the discovery of the Enceladus plume,” says Robert Pappalardo, a planetary scientist at the Jet Propulsion Laboratory in Pasadena, California, who was not involved in the research.

Astronomers have suspected that plumes like this existed on Europa for quite some time. The theoretical work seemed to suggest it, but observations just couldn’t find it – until now.

“It’s a first-time discovery, and we need to go back and look some more,” says team member Joachim Saur, a planetary scientist at the University of Cologne in Germany.

Saur and his teammates first tried to find these plumes several times, to no avail. But in 2012, they tried again, once in November, and once in December. The November survey came up empty, but just as they were about to give up hope, they found something in December: blobs of hydrogen and oxygen near Europa’s South Pole. They found this not through chance, but by focusing more on when they looked at it. They scheduled the observation for then the satellite is farthest away from its planet, when changes in the tidal forces cause additional stress in the icy crust. This could explain why other researchers haven’t been able to observe the plumes, and it also gives a very good starting point for future observations.

The plumes are approximately 200 km high – This is many times the height suggested by most theoretical research. The plumes may or may not reach deep into the liquid ocean – the heat generated by the friction of ice rubbing against itself might melt parts of the icy crust and feed the plumes. Either way, this is another thing to focus on for the 2022 European Space Agency mission which is set for Europa.

Zonal flows in Europa-like ocean simulation. Image credit: University of Texas Institute for Geophysics.

Jupiter’s icy moon, Europa, could harbor life according to report

We’ve written extensively before about the life harboring possibilities of Jupiter’s moon, the icy Europa. The moon is believed to be the likeliest candidate in our solar system, besides our own planet, capable of supporting life. Recently, a report compiled by researchers at University of Texas at Austin, the Georgia Institute of Technology, and the Max Planck Institute for Solar System Research modeled ocean currents and patterns beneath the moon’s icy crust and found it is likely these create enough heat and energy transfer to sustain life.

Zonal flows in Europa-like ocean simulation. Image credit: University of Texas Institute for Geophysics.

Zonal flows in Europa-like ocean simulation. Image credit: University of Texas Institute for Geophysics.

Previously, scientists have relied on valuable magnotometer readings supplied by the Galileo spacecraft, which orbits Europa, to estimate how conditions are like beneath the ice. This time, the researchers took a reverse path and looked at the effects to determine the cause. Namely, attention was shifted towards disrupted ice on the moon’s surface known as chaos terrains.

“The chaos terrains, which are concentrated in Europa’s equatorial region, could result from convection in Europa’s ice shell, accelerated by heat from the ocean,” explained lead author Krista Soderlund, from the University of Texas. “The heat transfer and possible marine ice formation may be helping form diapirs, or warm compositionally buoyant plumes of ice that rise through the shell.”

A warm ocean beneath an icy moon

The scientists compiled a numerical model of Europa’s ocean circulation and found  that warm rising ocean currents near the equator and subsiding currents in latitudes closer to the poles could account for the location of chaos terrains and other features of Europa’s surface. The report follows that these patterns could help intensive natural turbulence, increasing heat transfer near the equator and initiate upwelling ice pulses that create features such as the chaos terrains. To support their reasoning, the researchers liken their conclusions to similar phenomenon observed on Earth.

“This tells us foundational aspects of ocean physics,” notes co-author Britney Schmidt, assistant professor at the Georgia Institute of Technology. More importantly, adds Schmidt, if the study’s hypothesis is correct, it shows that Europa’s oceans are very important as a controlling influence on the surface ice shell, offering proof of the concept that ice-ocean interactions are important to Europa.

“That means more evidence that the ocean is there, that it’s active, and there are interesting interactions between the ocean and ice shell,” says Schmidt, “all of which makes us think about the possibility of life on Europa.”

When the  European Space Agency’s JUICE mission (JUpiter ICy moons Explorer) will be deployed to Europa, it will offer the necessary tools to test this hypothesis by probing into the characteristics of the ocean and ice shell through two flyby observations. NASA’s Europa Clipper mission concept, under study, would complement the view with global measurements.

Findings were reported in a paper published in the journal Nature Geoscience.