Antarctic lake, ho! Nearly twenty years ago Russian scientists began drilling through the over two miles of ice above Lake Vostok, a gigantic underground lake in Antarctica that hasn’t seen the surface in 20 million years. The pristine lake was reached last week, prompting a flurry of discussion among scientists and members of the media about how the Russian team could keep from contaminating it and whether unusual microbial life would be found there. Kept warm and liquid by heat from the center of the Earth, Lake Vostok, the largest in a chain of about 200 underground (or under-ice) lakes, is similar to the oceans supposed to exist below the surface on moons Enceladus and Europa, which makes this an exciting time to be an astrobiologist. Or, really, anyone interested in the origins of life.
It can be hard to reconstruct in your head the long, drawn-out process of reaching the lake when poring over the recent news stories on this topic. But a nice graphic put together by Nature News gives a blow-by-blow: In 1990, scientists began drilling at Vostok Station, the Russians’ Antarctic base, returning every summer to continue the task. At first they were drilling to remove ice cores that would provide data on climate, but by the mid-1990s, scientists had realized that a huge lake was deep below the surface. To protect the lake from contamination by the drilling fluids, which include kerosene, the team agreed they would melt the last bit of ice using a thermal probe instead of the drill (we don’t know yet if they did in fact follow the plan). As they got deeper into the ice, the drill became stuck, but trying another route met with success on February 5th.
[via Nature News]
Image courtesy of Nature News, created from Lukin, V. & Bulat, S. Geophys. Monogr. Ser. 192, 187–197 (2011).
What’s the News: Jupiter’s moon Io is more volcanically active than any other object in our solar system, releasing 30 times more heat than Earth through volcanism. It’s thought that Jupiter’s gravity pulls so hard on the moon and causes so much friction that the resulting thermal energy melts a huge amount of underground rock, feeding Io’s 400 active volcanoes.
For years, astronomers have debated whether Io’s spewing lava comes from isolated pockets of magma or a layer that spans the entire moon. Astronomers have now peered into Io’s interior for the first time, discovering that it has a global sea of magma roughly 30 miles thick. “It turns out Io was continually giving off a ‘sounding signal’ in Jupiter’s … magnetic field that matched what would be expected from molten or partially molten rocks deep beneath the surface,” lead researcher Krishan Khurana told Wired. Read More
There’s a lot more going on beneath those huge sheets of Antarctic ice than you might think. NASA researchers say they uncovered a major surprise in December: The team drilled an eight-inch hole and stuck a video camera 600 feet down, hoping to observe the underbelly of the thick ice sheet. To their amazement, a curious critter swam into view and clung to the video camera’s cable [Washington Post]. The three-inch crustacean in their video (and pictured in the image here) is a Lyssianasid amphipod, a relative of a shrimp. The team also retrieved what they believe to be a tentacle from a jellyfish.
“We were operating on the presumption that nothing’s there,” said NASA ice scientist Robert Bindschadler, who will be presenting the initial findings and a video at an American Geophysical Union meeting Wednesday. “It was a shrimp you’d enjoy having on your plate” [AP]. Indeed, researchers previously believed that nothing more complex than microbes could live in such a hostile place, beneath an ice sheet in total darkness. While complex organisms have shown up before in retreating glaciers, this seems to be the first time any have been found 600 feet down below an intact sheet of ice.
Life sure turns up in the darnedest places. The latest discovery comes from Blood Falls, a rusty red discolouration on the face of the Taylor Glacier in Antarctica [that] occasionally gushes forth a transparent, briny, iron-rich liquid that quickly oxidizes and turns red, staining the ice below [Nature News].
The source of that water is an intensely salty lake trapped beneath 1,300 feet of ice, and a new study has now found that microbes have carved out a niche for themselves in that inhospitable environment, living on sulfur and iron compounds. The bacteria colony has been isolated there for about 1.5 million years, researchers say, ever since the glacier rolled over the lake and created a cold, dark, oxygen-poor ecosystem.
The next stop in the search for life in outer space will be Jupiter’s ice-covered moon Europa. NASA announced plans on Wednesday to launch a probe to the moon in 2020, a mission that could cost $3 billion and will focus on the possibility that in the gigantic ocean thought to be hidden under the moon’s thick cover of ice is a habitable zone where rudimentary forms of life could exist…. What makes Europa so important, said Robert Pappalardo, a senior research scientist at [NASA], is that “icy satellites are the most common potentially habitable environment in the outer solar system,” and therefore could be common throughout the universe. Understanding how they function, and whether they are indeed a good home for life, is key to answering the “are we alone” question” [Los Angeles Times].
After years of debate over the destination for NASA’s next flagship mission, the agency finally homed in on Europa, the smallest of Jupiter’s four large moons, because the mission would be easier to accomplish than other moons of interest orbiting Jupiter or Saturn.
The mission will seek to “produce a global map in preparation for a journey many years in the future that would land on the moon. Using radar and other devices, the probe will try to verify the thickness of the ice sheet and determine the presence of the ocean covering the 2,000-mile diameter moon. “Europa is tremendously exciting,” said Jim Green, director of the Planetary Sciences Division at NASA. “It may have more water underground than the Earth” [Los Angeles Times].
Which celestial bodies are more likely to host extraterrestrial life: Saturn’s hazy moon Titan and water-spewing moon Enceladus, or Jupiter’s icy moons Europa and Ganymede, which may have liquid oceans beneath their frozen crusts? That’s the difficult question facing NASA and the European Space Agency (ESA) as they try to decide where to send the next planetary probe. By the end of this month, agency officials plan to pick a destination for a massive mission, costing nearly US$4 billion, to be launched around 2020 for the distant reaches of the Solar System. The battle pits Titan, which recent discoveries have made the cool new kid on the block, against Jupiter’s moon Europa, which has long sat atop community wish lists [Nature News].
In advance of that decision, the space agencies have released details of the dueling proposals. The potential Saturn mission would follow up the remarkable discoveries made by the Nasa/Esa Cassini-Huygens mission which continues to operate at the ringed planet…. Cassini has sent back data that indicates Titan is akin to a primitive – albeit frozen – Earth. It has a thick atmosphere and is rich in organic (carbon-rich) molecules [BBC News]. The plan calls for an orbiter that would release a hot air balloon to drift in Titan’s hazy atmosphere and would drop a lander to the surface, where it could float on one of moon’s lakes of liquid ethane and methane. The orbiter would also dip into the atmosphere of Enceladus, which has fired imaginations with the revelation that it has geysers that spew jets of icy water into space.
When NASA’s Cassini spacecraft swooped past Saturn‘s moon Enceladus last year, it got a close-up view of the water vapor and ice plumes that stream away from the small moon. After analyzing the data, researchers say the evidence suggests that the material in the plumes originates as liquid water trapped beneath the moon’s icy surface, which increases the possibility that microbial, extraterrestrial life could exist in the lakes. “We think liquid water is necessary for life and there is more evidence that there is liquid water there,” said lead researcher Candice Hansen…. Scientists are aware of only three places where liquid water exists near the surface of a planet or other body – Earth, Jupiter’s moon Europa and now Enceladus [Telegraph].
Researchers identified four distinct jets within the plume where the water vapor appears to be traveling faster than 1,300 miles per hour. Such high speeds imply that the jets are fed by pressurised water vapour that shoots through narrow openings – which act like rocket nozzles – in the moon’s icy surface. The simplest way to generate such pressures is by evaporating a reservoir of liquid water that lies close to the moon’s surface [New Scientist], researchers say.