Earth Ejecta Could Seed Life On Europa 130
KentuckyFC writes "Various astronomers have studied how far rocks can travel through space after being ejected from Earth. Their conclusion is that it's relatively easy for bits of Earth to end up on the Moon or Venus, but very little would get to Mars because it would have to overcome gravity from both the Sun and the Earth. Now, the biggest ever simulation of Earth ejecta confirms this result — with a twist. The simulation shows that Jupiter is a much more likely destination than Mars. So bits of Earth could have ended up on Jovian satellites such as Europa. Astrobiologists estimate that Earth's hardiest organisms can survive up to 30,000 years in space, which means that if conditions are just right, Earth ejecta could seed life there."
LHB is Late Heavy Bombardment (Score:2, Informative)
To save anyone else the bother of googling it to be reminded.
Misleading summary (Score:4, Informative)
Mars rocks have been found on Earth, and it has been a standard assumption in planetary science for some time now that Earth rocks have also been going to Mars by the same mechanism. You wouldn't know it from the summary, but the actual paper [arxiv.org] also predicts a significant rate of mass exchange Earth -> Mars -
Gladman et al. (2005) estimated the collision rate with Mars to be about 2 orders of magnitude lower that found on the basis of our simulations. However, as also noted in their paper, our results for Mars are within the known typical errors of such probability estimations. ... Both results, definite collisions with Mars and Jupiter, are of astrobiological significance,...
Re:Europa and the NASA Twins (Score:4, Informative)
The problem with Europa is that the interesting bits we want to get at are under (at least) 20 kilometers of ice. Whoever figures out how to breach that without destroying the environment beneath is going to be a winner in the big NASA lottery, and enable a lot of exciting exploration. Callisto probably has a similar subsurface ocean, for instance -
If I understand what I've read about Europa, we may not need to get through the ice at all. Due to tidal tugging, Europa is full of cracks. When those cracks form, it is believed that liquid water cycles to the surface and freezes again. It's Europa's version of plate tectonics. We should be able to get an excellent idea of what is below the surface by taking a sample of the surface ice on the surface near these cracks or even within the cracks themselves. As a bonus, whatever we find will be pre-frozen. Kinda like the frozen veggie aisle at your local grocer.
Why we have not sent a probe to land on Europa by now is beyond me.