Europa Archives

July 14, 2014December 23, 2015 by Elizabeth Howell

The Search for Alien Life Could Get A Boost From NASA’s Next-Generation Rocket

Artist's conception of NASA's Space Launch System with Orion crewed deep space capsule. Credit: NASA

In three years, NASA is planning to light the fuse on a huge rocket designed to bring humans further out into the solar system.

We usually talk about SLS here in the context of the astronauts it will carry inside the Orion spacecraft, which will have its own test flight later in 2014. But today, NASA advertised a possible other use for the rocket: trying to find life beyond Earth.

At a symposium in Washington on the search for life, NASA associate administrator John Grunsfeld said SLS could serve two major functions: launching bigger telescopes, and sending a mission on an express route to Jupiter’s moon Europa.

The James Webb Space Telescope, with a mirror of 6.5 meters (21 feet), will in part search for exoplanets after its launch in 2018. Next-generation telescopes of 10 to 20 meters (33 to 66 feet) could pick out more, if SLS could bring them up into space.

“This will be a multi-generational search,” said Sara Seager, a planetary scientist and physicist at the Massachusetts Institute of Technology. She added that the big challenge is trying to distinguish a planet like Earth from the light of its parent star; the difference between the two is a magnitude of 10 billion. “Our Earth is actually extremely hard to find,” she said.

Much like our solar system, Kepler-62 is home to two habitable zone worlds. The small shining object seen to the right of Kepler-62f is Kepler-62e. Orbiting on the inner edge of the habitable zone, Kepler-62e is roughly 60 percent larger than Earth. Image credit: NASA Ames/JPL-Caltech.

While the symposium was not talking much about life in the solar system, Europa is considered one of the top candidates due to the presence of a possible subsurface ocean beneath its ice. NASA is now seeking ideas for a mission to this moon, following news that water plumes were spotted spewing from the moon’s icy south pole. A mission to Europa would take seven years with the technology currently in NASA’s hands, but the SLS would be powerful enough to speed up the trip to only three years, Grunsfeld said.

And that’s not all that SLS could do. If it does bring astronauts deeper in space as NASA hopes it will, this opens up a range of destinations for them to go to. Usually NASA talks about this in terms of its human asteroid mission, an idea it has been working on and pitching for the past year to a skeptical, budget-conscious Congress.

But in passing, John Mather (NASA’s senior project scientist for Webb) said it’s possible astronauts could be sent to maintain the telescope. Webb is supposed to be parked in a Lagrange point (gravitationally stable location) in the exact opposite direction of the sun, almost a million miles away. It’s a big contrast to the Hubble Space Telescope, which was conveniently parked in low Earth orbit for astronauts to fix every so often with the space shuttle.

An Artist's Conception of the James Webb Space Telescope. Credit: ESA. — An Artist’s Conception of the James Webb Space Telescope. Credit: ESA.

While NASA works on the funding and design for larger telescope mirrors, Webb is one of the two new space telescopes it is focusing on in the search for life. Webb’s infrared eyes will be able to peer at solar systems being born, once it is launched in 2018. Complementary to that will be the Transiting Exoplanet Survey Satellite, which will fly in 2017 and examine planets that pass in front of their parent stars to find elements in their atmospheres.

The usual cautions apply when talking about this article: NASA is talking about several missions under development, and it is unclear yet what the success of SLS or any of these will be until they are battle-tested in space.

But what this discussion does show is the agency is trying to find many purposes for its next-generation rocket, and working to align it to astrophysics goals as well as its desire to send humans further out in the solar system.

July 9, 2014December 23, 2015 by Jason Major

A New Image of Europa Emerges

Europa's icy, cracked surface imaged by NASA's Galileo spacecraft Credit: NASA/JPL-Caltech/SETI Institute

Eureka – it’s Europa! And a brand-new image of it, too! (Well, kinda sorta.)

The picture above, showing the icy moon’s creased and cracked surface, was made from images acquired by NASA’s Galileo spacecraft during its exploration of Jupiter and its family of moons in 1997 and 1998. While the data itself isn’t new per se the view seen here has never been released by JPL, and so it’s new to you! (And to me too.)

Europa's bizarre surface features suggest an actively churning ice shell above a salty liquid water ocean. Credit: JPL — Europa’s bizarre surface features suggest an actively churning ice shell above a salty liquid water ocean. Credit: JPL

The original high-resolution images were acquired on Nov. 6, 1997, in greyscale and colorized with data acquired during a later pass by Galileo in 1998. The whiter areas are regions of relatively pure water ice, while the rusty red bands are where ice has mixed with salts and organic compounds that have oozed up from deeper within Europa.

The entire image area measures about 101 by 103 miles across (163 km x 167 km).

Europa has long been one of the few places we know of outside our own planet where life could very well have evolved and potentially still exist. Getting a peek below the icy moon’s frozen crust — or even a taste of the recently-discovered water vapor spraying from its south pole — is all we’d need to further narrow down the chances that somewhere, something could be thriving in Europa’s subsurface seas. Get a planetary scientist’s perspective in a video interview with Dr. Mike Brown here.

Launched in October 1989, the Galileo spacecraft arrived at Jupiter in December 1995. Through primary and extended missions Galileo explored the giant planet and its family of moons until plunging into Jupiter’s atmosphere on September 21, 2003. Learn more about Galileo here, and check out some of the amazing images it acquired on the CICLOPS imaging diary page here.

Source: NASA’s Planetary Photojournal

December 17, 2013December 23, 2015 by Shannon Hall

Lithopanspermia: How Earth May Have Seeded Life on Other Solar System Bodies

The theory of Lithopanspermia states that life can be shared between planets within a planetary system. Credit: NASA

With the recent discovery that Europa has geysers, and therefore definitive proof of a liquid ocean, there’s a lot of talk about the possibility of life in the outer solar system.

According to a new study, there is a high probably that life spread from Earth to other planets and moons during the period of the late heavy bombardment — an era about 4.1 billion to 3.8 billion years ago — when untold numbers of asteroids and comets pummeled the Earth. Rock fragments from the Earth would have been ejected after a large meteoroid impact, and may have carried the basic ingredients for life to other solar system bodies.

These findings, from Pennsylvania State University, strongly support lithopanspermia: the idea that basic life forms can be distributed throughout the solar system via rock fragments cast forth by meteoroid impacts.

Strong evidence for lithopanspermia is found within the rocks themselves. Of the over 53,000 meteorites found on Earth, 105 have been identified as Martian in origin. In other words an impact on Mars ejected rock fragments that then hit the Earth.

The researchers simulated a large number of rock fragments ejected from the Earth and Mars with random velocities. They then tracked each rock fragment in n-body simulations — models of how objects gravitationally interact with one another over time — in order to determine how the rock fragments move among the planets.

“We ran the simulations for 10 million years after the ejection, and then counted up how many rocks hit each planet,” said doctoral student Rachel Worth, lead author on the study.

Their simulations mainly showed a large number of rock fragments falling into the Sun or exiting the solar system entirely, but a small fraction hit planets. These estimations allowed them to calculate the likelihood that a rock fragment might hit a planet or a moon. They then projected this probability to 3.5 billion years, instead of 10 million years.

In general the number of impacts decreased with the distance away from the planet of origin. Over the course of 3.5 billion years, tens of thousands of rock fragments from the Earth and Mars could have been transferred to Jupiter and several thousand rock fragments could have reached Saturn.

“Fragments from the Earth can reach the moons of Jupiter and Saturn, and thus could potentially carry life there,” Worth told Universe Today.

The researchers looked at Jupiter’s Galilean satellites: Io, Europa, Ganymede and Callisto and Saturn’s largest moons: Titan and Enceladus. Over the course of 3.5 billion years, each of these moons received between one and 10 meteoroid impacts from the Earth and Mars.

It’s statistically possible that life was carried from the Earth or Mars to one of the moons of Jupiter or Saturn. During the period of late bombardment the solar system was much warmer and the now icy moons of Saturn and Jupiter didn’t have those protective shells to prevent meteorites from reaching their liquid interiors. Even if they did have a thin layer of ice, there’s a large chance that a meteorite would fall though, depositing life in the ocean beneath.

In the case of Europa, six rock fragments from the Earth would have hit it over the last 3.5 billion years.

It has previously been thought that finding life in Europa’s oceans would be proof of an independent origin of life. “But our results suggest we can’t assume that,” Worth said. “We would need to test any life found and try to figure out whether it descended from Earth life, or is something really new.”

The paper has been accepted for publication in the journal Astrobiology and is available for download here.

December 12, 2013December 23, 2015 by Jason Major

Hubble Discovers Water Plumes Erupting from Europa

UV observations from Hubble show the size of water vapor plumes coming from Europa's south pole (NASA, ESA, and M. Kornmesser)

It’s been known since 2005 that Saturn’s 300-mile-wide moon Enceladus has geysers spewing ice and dust out into orbit from deep troughs that rake across its south pole. Now, thanks to the Hubble Space Telescope (after 23 years still going strong) we know of another moon with similar jets: Europa, the ever-enigmatic ice-shelled moon of Jupiter. This makes two places in our Solar System where subsurface oceans could be getting sprayed directly into space — and within easy reach of any passing spacecraft.

(Psst, NASA… hint hint.)

The findings were announced today during the meeting of the American Geophysical Union in San Francisco.

“The discovery that water vapor is ejected near the south pole strengthens Europa’s position as the top candidate for potential habitability,” said lead author Lorenz Roth of the Southwest Research Institute (SwRI) in San Antonio, Texas. “However, we do not know yet if these plumes are connected to subsurface liquid water or not.”

The 125-mile (200-km) -high plumes were discovered with Hubble observations made in December 2012. Hubble’s Space Telescope Imaging Spectrograph (STIS) detected faint ultraviolet light from an aurora at the Europa’s south pole. Europa’s aurora is created as it plows through Jupiter’s intense magnetic field, which causes particles to reach such high speeds that they can split the water molecules in the plume when they hit them. The resulting oxygen and hydrogen ions revealed themselves to Hubble with their specific colors.

Unlike the jets on Enceladus, which contain ice and dust particles, only water has so far been identified in Europa’s plumes. (Source)

Rendering showing the location and size of water vapor plumes coming from Europa's south pole. — Rendering showing the location and size of water vapor plumes coming from Europa’s south pole.

The team suspects that the source of the water is Europa’s long-hypothesized subsurface ocean, which could contain even more water than is found across the entire surface of our planet.

“If those plumes are connected with the subsurface water ocean we are confident exists under Europa’s crust, then this means that future investigations can directly investigate the chemical makeup of Europa’s potentially habitable environment without drilling through layers of ice,” Roth said. “And that is tremendously exciting.”

One other possible source of the water vapor could be surface ice, heated through friction.

Cassini image of ice geysers on Enceladus (NASA/JPL/SSI)

In addition the Hubble team found that the intensity of Europa’s plumes, like those of Enceladus, varies with the moon’s orbital position around Jupiter. Active jets have been seen only when Europa is farthest from Jupiter. But the researchers could not detect any sign of venting when Europa is closer.

One explanation for the variability is Europa undergoes more tidal flexing as gravitational forces push and pull on the moon, opening vents at larger distances from Jupiter. The vents get narrowed or even seal off entirely when the moon is closest to Jupiter.

Still, the observation of these plumes — as well as their varying intensity — only serves to further support the existence of Europa’s ocean.

“The apparent plume variability supports a key prediction that Europa should tidally flex by a significant amount if it has a subsurface ocean,” said Kurt Retherford, also of SwRI.

(Science buzzkill alert: although exciting, further observations will be needed to confirm these findings. “This is a 4 sigma detection, so a small uncertainly that the signal is just noise in the instruments,” noted Roth.)

“If confirmed, this new observation once again shows the power of the Hubble Space Telescope to explore and opens a new chapter in our search for potentially habitable environments in our solar system.”

– John Grunsfeld, NASA’s Associate Administrator for Science

So. Who’s up for a mission to Europa now? (And unfortunately in this case, Juno doesn’t count.)

“Juno is a spinning spacecraft that will fly close to Jupiter, and won’t be studying Europa,” Kurt Retherford told Universe Today. “The team is looking hard how we can optimize, maybe looking for gases coming off Europa and look at how the plasma interacts with environment, so we really need a dedicated Europa mission.”

We couldn’t agree more.

The findings were published in the Dec. 12 online issue of Science Express.

Sources: Hubble news releases (US and ESA)

Image credits:
Graphic Credit: NASA, ESA, and L. Roth (Southwest Research Institute and University of Cologne, Germany)
Science Credit: NASA, ESA, L. Roth (Southwest Research Institute and University of Cologne, Germany), J. Saur (University of Cologne, Germany), K. Retherford (Southwest Research Institute), D. Strobel and P. Feldman (Johns Hopkins University), M. McGrath (Marshall Space Flight Center), and F. Nimmo (University of California, Santa Cruz)

December 11, 2013December 23, 2015 by Elizabeth Howell

The Search For Life On Europa Could Center On Celestial Party-Crashers

Jupiter's moon, Europa, appears to have clay-like minerals on it (visible in blue in the false-color patch, amid red-colored water ice). The information came from new data analysis from NASA's Galileo mission, which concluded in 2003. The backdrop is a mosaic of visual-light images from Galileo's Near-Infrared Mapping Spectrometer. Credit: NASA/JPL-Caltech/SETI

The cool thing about space missions is long after they conclude, the data can yield the most interesting information. Here’s an example: Jupiter’s moon Europa may have a ripe spot for organic materials to take root.

Scouring the data from NASA’s past Galileo mission — which ended a decade ago — scientists unveiled an area with “clay-like minerals” on it that came to be after an asteroid or comet smashed into the surface. The connection? These celestial party-crashers often carry organics with them.

“Organic materials, which are important building blocks for life, are often found in comets and primitive asteroids,” stated Jim Shirley, a research scientist at NASA’s Jet Propulsion Laboratory. “Finding the rocky residues of this comet crash on Europa’s surface may open up a new chapter in the story of the search for life on Europa.”

Europa is considered one of the best spots in our solar system to look for life, due to the ocean lurking beneath its icy surface, surface salts that can provide energy, and a source of heat as the mighty Jupiter squeezes and releases the moon like a tennis ball.

The minerals (called phyllosilicates) emerged after Shirley’s team ran a new analysis on infrared pictures snapped by Galileo in 1998, basically working to refine the signal out of the images (which are much lower quality than what we are capable of today).

After the analysis, the phyllosilicates appeared in a “broken ring”, NASA stated, about 75 miles (120 kilometers) away from a crater site. The crater itself is about 20 miles (30 kilometers) in diameter. Scientists are betting that the ring of phyllosilicates is debris (“splash back of material”, NASA says), after a celestial body struck at or around a 45 degree angle from vertical. It’s unlikely the phyllosilicates came from Europa’s ocean given the crust, which can be as thick as 60 miles (100 kilometers).

Europa Report was a 2013 film that focused on a human mission to the Jovian moon. Poster by Start Motion Pictures.

“If the body was an asteroid, it was likely about 3,600 feet (1,100 meters) in diameter. If the body was a comet, it was likely about 5,600 feet (1,700 meters) in diameter. It would have been nearly the same size as the comet ISON before it passed around the sun a few weeks ago,” NASA stated.

To be clear, nobody has found organic materials on Europa directly, and even if they were detected it would then be another feat of science to determine if they related to life or not. This does, however, lend credence to theories that life came to Earth through comets and asteroids.

Ample fodder to consider as the community waits for the European Space Agency’s JUICE (JUpiter ICy moons Explorer) to get going to Europa and Jupiter upon its expected launch in 2022. The probe should arrive there in 2030.

Shirley will give a talk on this topic at the American Geophysical Union’s fall meeting on Friday.

Source: NASA

October 11, 2013December 23, 2015 by Jason Major

These Antarctic Research Photos Look Like Exploration on Another Planet

Researchers work in the Antarctic polar night during a storm (Credit: Stefan Hendricks, Alfred Wegner Institute)

Some day, human explorers will land a spacecraft on the surface of Europa, Enceladus, Titan, or some other icy world and investigate first-hand the secrets hidden beneath its frozen surface. When that day comes — and it can’t come too soon for me! — it may look a lot like this.

One of a series of amazing photos by Stefan Hendricks taken during the Antarctic Winter Ecosystem & Climate Study (AWECS), a study of Antarctica’s sea ice conducted by the Alfred Wegener Institute in Germany, the image above shows researchers working on the Antarctic ice during a winter snowstorm. It’s easy to imagine them on the night-side surface of Europa, with the research vessel Polarstern standing in for a distant illuminated lander (albeit rather oversized).

Hey, one can dream!

One of the goals of the campaign, called CryoVex, was to look at how ESA’s CryoSat mission can be used to understand the thickness of sea ice in Antarctica. The extent of the Antarctic sea ice in winter is currently more than normal, which could be linked to changing atmospheric patterns.

Antarctica’s massive shelves of sea ice in winter are quite dramatic landscapes, and remind us that there are very alien places right here on our own planet.

See this and more photos from the mission on the ESA website (really, go check them out!)

August 19, 2013December 23, 2015 by Elizabeth Howell

Poof! This Spacecraft Could Get Under A Planet’s Skin

A subsurface spacecraft prototype is deliberately slammed into 10 tonnes of ice in a rocket facility. Credit: European Space Agency/YouTube (screenshot)

If you want to get inside a planet or moon fast, the European Space Agency says lobbing a spacecraft at the surface might be a good approach.

This concept may sound like suicide. A recent prototype test, however, shows the spacecraft structure is mostly okay. Next step is figuring out what can survive on the inside.

ESA, like NASA and other agencies, isn’t afraid to test out new landing concepts if they suit better than the traditional ones (which use rockets and/or parachutes to land a spacecraft softly on the surface). Witness the Curiosity rover’s “seven minutes of terror” concept as a successful example.

Imagine that you want to look at water below the surface of Mars, or (like the people in Europa Report) you wish to plumb into the ice of Jupiter’s moon, Europa. One option could be a drill. Another one could be a subsurface spacecraft.

“One benefit over landers and rovers is that penetrators provide access to the subsurface without the need for additional drilling or digging,” ESA stated.

To test this out, engineers put 12 solid-propellant boosters on to a 44-pound (20 kilogram) prototype and fired it at almost the speed of sound at sea level: 1,118 feet a second (341 meters/second). (More technical details on the test).

The 1.5-second test, shown in the video, saw the prototype careening into 10 tonnes of ice at a deceleration of 24,000 times the force of gravity. Astronauts, by contrast, usually only withstand 3-4 g when going into space.

The scuffed and dented spacecraft was retrieved successfully, and now ESA is reviewing how well the internal structure held up in the chaos. They also plan to develop battery and communications systems that could somehow survive intact.

High-speed tests are not only useful for spacecraft landings, but also for meteor simulations.

Most meteors are comet dust striking at the atmosphere at speeds so high, they vaporiz in a blaze of light. This is a meteor from the Leonid shower in 2001. Credit: Bob King

An article in Wired recently covered the progress of the NASA Ames Vertical Gun range in its nearly 50 years of operation.

“Though it’s called a gun, the facility doesn’t look much like any firearm you’ve ever seen,” wrote Adam Mann. “The main chassis is a long metal barrel as thick as a cannon mounted on an enormous red pole that forks at the end into two legs.”

Check out how it’s studying meteor impacts on Mars in the Wired article.

April 5, 2013December 23, 2015 by Jason Major

Hydrogen Peroxide Could Feed Life on Europa

According to research by NASA astronomers using the next-generation optics of the 10-meter Keck II telescope, Jupiter’s ice-encrusted moon Europa has hydrogen peroxide across much of the surface of its leading hemisphere, a compound that could potentially provide energy for life if it has found its way into the moon’s subsurface ocean.

“Europa has the liquid water and elements, and we think that compounds like peroxide might be an important part of the energy requirement,” said JPL scientist Kevin Hand, the paper’s lead author. “The availability of oxidants like peroxide on Earth was a critical part of the rise of complex, multicellular life.”

The paper, co-authored by Mike Brown of the California Institute of Technology in Pasadena, analyzed data in the near-infrared range of light from Europa using the Keck II Telescope on Mauna Kea, Hawaii, over four nights in September 2011. The highest concentration of peroxide found was on the side of Europa that always leads in its orbit around Jupiter, with a peroxide abundance of 0.12 percent relative to water. (For perspective, this is roughly 20 times more diluted than the hydrogen peroxide mixture available at drug stores.) The concentration of peroxide in Europa’s ice then drops off to nearly zero on the hemisphere of Europa that faces backward in its orbit.

Hydrogen peroxide was first detected on Europa by NASA’s Galileo mission, which explored the Jupiter system from 1995 to 2003, but Galileo observations were of a limited region. The new Keck data show that peroxide is widespread across much of the surface of Europa, and the highest concentrations are reached in regions where Europa’s ice is nearly pure water with very little sulfur contamination.

This color composite view combines violet, green, and infrared images of Europa acquired by Galileo in 1997 for a view of the moon in natural color (left) and in enhanced color (right). Credit: NASA/JPL/University of Arizona

The peroxide is created by the intense radiation processing of Europa’s surface ice that comes from the moon’s location within Jupiter’s strong magnetic field.

“The Galileo measurements gave us tantalizing hints of what might be happening all over the surface of Europa, and we’ve now been able to quantify that with our Keck telescope observations,” Brown said. “What we still don’t know is how the surface and the ocean mix, which would provide a mechanism for any life to use the peroxide.”

The scientists think hydrogen peroxide is an important factor for the habitability of the global liquid water ocean under Europa’s icy crust because hydrogen peroxide decays to oxygen when mixed into liquid water. “At Europa, abundant compounds like peroxide could help to satisfy the chemical energy requirement needed for life within the ocean, if the peroxide is mixed into the ocean,” said Hand.

(Source: NASA)

What’s notable to add, on March 26, 2013, the U.S. President signed a bill that would increase the budget for NASA’s planetary science program as well as provide $75 million for the exploration of Europa. Exactly how the funds will be used isn’t clear — perhaps for components on the proposed Europa Clipper mission? — but it’s a step in the right direction for learning more about this increasingly intriguing world. Read more on SETI’s Destination: Europa blog.

March 5, 2013April 26, 2016 by Nancy Atkinson

Evidence for a Deep Ocean on Europa Might be Found on its Surface

Astronomers hypothesize that chloride salts bubble up from the icy moon's global liquid ocean and reach the frozen surface where they are bombarded with sulfur from volcanoes on Jupiter's largest moon, Io. This illustration of Europa (foreground), Jupiter (right) and Io (middle) is an artist's concept. Credit: Keck Observatory.

Astronomer Mike Brown and his colleague Kevin Hand might be suffering from “Pump Handle Phobia,” as radio personality Garrison Keillor calls it, where those afflicted just can’t resist putting their tongues on something frozen to see if it will stick. But Brown and Hand are doing it all in the name of science, and they may have found the best evidence yet that Europa has a liquid water ocean beneath its icy surface. Better yet, that vast subsurface ocean may actually shoot up to Europa’s surface, on occasion.

In a recent blog post, Brown pondered what it would taste like if he could lick the icy surface of Jupiter’s moon Europa. “The answer may be that it would taste a lot like that last mouthful of water that you accidentally drank when you were swimming at the beach on your last vacation. Just don’t take too long of a taste. At nearly 300 degrees (F) below zero your tongue will stick fast.”

His ponderings were based on a new paper by Brown and Hand which combined data from the Galileo mission (1989 to 2003) to study Jupiter and its moons, along with new spectroscopy data from the 10-meter Keck II telescope in Hawaii.

The study suggests there is a chemical exchange between the ocean and surface, making the ocean a richer chemical environment.

“We now have evidence that Europa’s ocean is not isolated—that the ocean and the surface talk to each other and exchange chemicals,” said Brown, who is an astronomer and professor of planetary astronomy at Caltech. “That means that energy might be going into the ocean, which is important in terms of the possibilities for life there. It also means that if you’d like to know what’s in the ocean, you can just go to the surface and scrape some off.”

“The surface ice is providing us a window into that potentially habitable ocean below,” said Hand, deputy chief scientist for solar system exploration at JPL.

Europa’s ocean is thought to cover the moon’s whole globe and is about 100 kilometers (60 miles) thick under a thin ice shell. Since the days of NASA’s Voyager and Galileo missions, scientists have debated the composition of Europa’s surface.

Salts were detected in the Galileo data – “Not ‘salt’ as in the sodium chloride of your table salt,” Brown wrote in his blog, “Mike Brown’s Planets,” “but more generically ‘salts’ as in ‘things that dissolve in water and stick around when the water evaporates.’”

That idea was enticing, Brown said, because if the surface is covered by things that dissolve in water, that strongly implies that Europa’s ocean water has flowed on the surface, evaporated, and left behind salts.

But there were other explanations for the Galileo data, as Europa is constantly bombarded by sulfur from the volcanoes on Io, and the spectrograph that was on the Galileo spacecraft wasn’t able to tell the difference between salts and sulfuric acid.

But now, with data from the Keck Observatory, Brown and Hand have identified a spectroscopic feature on Europa’s surface that indicates the presence of a magnesium sulfate salt, a mineral called epsomite, that could have formed by oxidation of a mineral likely originating from the ocean below.

This view of Jupiter's moon Europa features several regional-resolution mosaics overlaid on a lower resolution global view for context. The regional views were obtained during several different flybys of the moon by NASA's Galileo mission. Image credit: NASA/JPL-Caltech/University of Arizona. — This view of Jupiter’s moon Europa features several regional-resolution mosaics overlaid on a lower resolution global view for context. The regional views were obtained during several different flybys of the moon by NASA’s Galileo mission. Image credit: NASA/JPL-Caltech/University of Arizona.

Brown and Hand started by mapping the distribution of pure water ice versus anything else. The spectra showed that even Europa’s leading hemisphere contains significant amounts of non-water ice. Then, at low latitudes on the trailing hemisphere — the area with the greatest concentration of the non-water ice material — they found a tiny, never-before-detected dip in the spectrum.

The two researchers tested everything from sodium chloride to Drano in Hand’s lab at JPL, where he tries to simulate the environments found on various icy worlds. At the end of the day, the signature of magnesium sulfate persisted.

The magnesium sulfate appears to be generated by the irradiation of sulfur ejected from the Jovian moon Io and, the authors deduce, magnesium chloride salt originating from Europa’s ocean. Chlorides such as sodium and potassium chlorides, which are expected to be on the Europa surface, are in general not detectable because they have no clear infrared spectral features. But magnesium sulfate is detectable. The authors believe the composition of Europa’s ocean may closely resemble the salty ocean of Earth.

While no one is going to be traveling to Europa to lick its surface, for now, astronomers will continue to use the modern giant telescopes on Earth to continue to “take spectral fingerprints of increasing detail to finally understand the mysterious details of the salty ocean beneath the ice shell of Europa,” Brown said.

Also, NASA is looking into options to explore Europa further. (Universe Today likes the idea of a big drill or submarine!)

But in the meantime what happens next? “We look for chlorine, I think,” Brown wrote. “The existence of chlorine as one of the main components of the non-water-ice surface of Europa is the strongest prediction that this hypothesis makes. We have some ideas on how we might look; we’re working on them now. Stay tuned.”

Read Brown & Hand’s paper.

Sources: Mike Brown’s Planets, Keck Observatory, JPL

November 30, 2012December 23, 2015 by Jason Major

In an Isolated, Ice-Covered Antarctic Lake Far Below Freezing, Life is Found

Lake Vida lies within one of Antarctica’s cold, arid McMurdo Dry Valleys (Photo: Desert Research Institute)

Even inside an almost completely frozen lake within Antarctica’s inland dry valleys, in dark, salt-laden and sub-freezing water full of nitrous oxide, life thrives… offering a clue at what might one day be found in similar environments elsewhere in the Solar System.

Researchers from NASA, the Desert Research Institute in Nevada, the University of Illinois at Chicago and nine other institutions have discovered colonies of bacteria living in one of the most isolated places on Earth: Antarctica’s Lake Vida, located in Victoria Valley — one of the southern continent’s incredibly arid McMurdo Dry Valleys.

These organisms seem to be thriving despite the harsh conditions. Covered by 20 meters (65 feet) of ice, the water in Lake Vida is six times saltier than seawater and contains the highest levels of nitrous oxide ever found in a natural body of water. Sunlight doesn’t penetrate very far below the frozen surface, and due to the hypersaline conditions and pressure of the ice water temperatures can plunge to a frigid -13.5 ºC (8 ºF).

Yet even within such a seemingly inhospitable environment Lake Vida is host to a “surprisingly diverse and abundant assemblage of bacteria” existing within water channels branching through the ice, separated from the sun’s energy and isolated from exterior influences for an estimated 3,000 years.

Originally thought to be frozen solid, ground penetrating radar surveys in 1995 revealed a very salty liquid layer (a brine) underlying the lake’s year-round 20-meter-thick ice cover.

“This study provides a window into one of the most unique ecosystems on Earth,” said Dr. Alison Murray, one of the lead authors of the team’s paper, a molecular microbial ecologist and polar researcher and a member of 14 expeditions to the Southern Ocean and Antarctic continent. “Our knowledge of geochemical and microbial processes in lightless icy environments, especially at subzero temperatures, has been mostly unknown up until now. This work expands our understanding of the types of life that can survive in these isolated, cryoecosystems and how different strategies may be used to exist in such challenging environments.”

Sterile environments had to be set up within tents on Lake Vida’s surface so the researchers could be sure that the core samples they were drilling were pristine, and weren’t being contaminated with any introduced organisms.

According to a NASA press release, “geochemical analyses suggest chemical reactions between the brine and the underlying iron-rich sediments generate nitrous oxide and molecular hydrogen. The latter, in part, may provide the energy needed to support the brine’s diverse microbial life.”

“This system is probably the best analog we have for possible ecosystems in the subsurface waters of Saturn’s moon Enceladus and Jupiter’s moon Europa.”

– Chris McKay, co-author, NASA’s Ames Research Center

What’s particularly exciting is the similarity between conditions found in ice-covered Antarctic lakes and those that could be found on other worlds in our Solar System. If life could survive in Lake Vida, as harsh and isolated as it is, could it also be found beneath the icy surface of Europa, or within the (hypothesized) subsurface oceans of Enceladus? And what about the ice caps of Mars? Might there be similar channels of super-salty liquid water running through Mars’ ice, with microbes eking out an existence on iron sediments?

“It’s plausible that a life-supporting energy source exists solely from the chemical reaction between anoxic salt water and the rock,” explained Dr. Christian Fritsen, a systems microbial ecologist and Research Professor in DRI’s Division of Earth and Ecosystem Sciences and co-author of the study.

“If that’s the case,” Murray added, “this gives us an entirely new framework for thinking of how life can be supported in cryoecosystems on earth and in other icy worlds of the universe.”

More research is planned to study the chemical interactions between the sediment and the brine as well as the genetic makeup of the microbial communities themselves.

The research was published this week in the Proceedings of the National Academy of Science (PNAS). Read more on the DRI press release here, and watch a video below showing highlights from the field research.

Funding for the research was supported jointly by NSF and NASA. Images courtesy the Desert Research Institute. Dry valley image credit: NASA/Landsat. Europa image: NASA/Ted Stryk.)