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Wednesday, 24 June 2015

Does Europa's ice hold the key to alien life?

Life's building blocks on Europa?
Europa is the second moon out in the Jupiter system of moons, and one of the most fascinating worlds we've come across. Why? Its looks maybe?

Above: Well wouldn't you be curious if you found a scratched pool ball thousands of miles across? Courtesy of NASA.
Not looks then - the gigantic cue ball look is soooo 2007. In one word the real reason is: Water. A world engulfing ocean of it in fact: Beneath Europa's icy surface all the evidence suggests (and there's a lot of it these days) that Europa has a global ocean, maybe hundreds of kilometres deep. The ocean is made from ice kept liquid by the way that Jupiter's gravity constantly kneads the moon's core into volcanic fury, the same process that drives the insanely huge levels of volcanic activity on Europa's neighbour, Io:

Above: If you're unclear about what makes Europa soooo interesting this should clear that up for you.
This doesn't just make Europa a unique place in our solar system*, it means that Europa has two of the major things needed (we think) for life: Lots of water and an energy source. But what about the all important third thing, organic chemistry? Well researchers from the  Earth-Life Science Institute, Tokyo Institute of Technology, may have found a way that the right chemical ingredients can make their way into Europa's ocean: C-type asteroids, and comets, are known to contain the basic chemical building blocks of life, such a nucleobases and amino aids.These are thought to have been formed in the interstellar dust clouds that preceded our solar system, and in the warm subsurface of protoplanets. Over time fragments of these protoplanets and comets would have rained onto Europa's ice... but that isn't enough to start life. 

Above: Comets like 67-P here might be the source of life's building blocks - one of the goals of the Rosetta mission is to find that out - but what makes those blocks come together? Courtesy of ESA.
What the Tokyo team have found is that the simple organic chemicals buried in the cold ice near Europa's surface will polymerise - which means join together to form more complex molecules. Over time these more complex molecules will be drawn into the ocean by the movement of the ice, and we know from lab experiments here on Earth that when molecules like these are mixed with water they can start to form life-like structures that do things like reproduce and adapt to their environment.

Does all this actually add up to life?
We don't know, but we're going to find out a lot more about Jupiter and Europa in the next decade or two: The JUNO mission will arrive at Jupiter to study the giant planet itself in almost exactly a year, and NASA is launching a dedicated mission just to study Europa itself in the 2020's. Here's a (40 minute long or so) video on the decision and the mission, from NASA:

Above: NASA announce that it intends to send a probe to Europa. About time! Courtesy of NASA.

For now though, the Tokyo team will have to content themselves with lab experiments and simulations. But someday soon they'll get to find out, from Europa itself, how close to the mark their research is. Their paper is here.

Elsewhere in the Universe:
Pluto-Charon animation:The image wizards over on have produced this animation of Pluto and Charon:

Above: See how the two worlds swig around each other? That's becuse Charon is so big compared to Pluto that ts gravity forces Pluto to Orbit Charon a bit as well. Courtesy of Fred_76 on

* Technically this doesn't even make Europa a unique place, as many icy worlds are suspected to harbour hidden seas and oceans, including Europa's other neighbour Ganymede, Saturn's moon Enceleadus, Pluto's moon Charon and possibly even the dwarf planet Ceres

Elsewhere on the internet:
How the Martian atmosphere changed
Stability of exomoon atmospheres
Going into space to see Earth's core
Ultra dark galaxies
Rosetta mission extended

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