Signs of Current Geological Activity on Europa
As far as extraterrestrial life goes, Europa would be quite far out. The moon basically has no atmosphere, and the planet warms to a regular high of 260 degrees Fahrenheit.
The beautiful image above is of Jupiter’s moon, Enceladus, in which jets of ice are being expelled through cracks in the surface up through its slight atmosphere.
This is relevant because as Europa orbits Jupiter, its slightly elliptical orbit brings it closer to Jupiter at certain points, and farther away at others. This change in gravitational pull, kneads the moon like bread, pulling it here and there. It is thought that this kneading would induce a heated core in the planet.
No one thought life could exist somewhere as harsh as Europa for a long time, but that all changed when we started discovering extremophile bacteria on Earth that lives in harshest of condition, in the frozen ice, on hydrothermal vents feeding of CO2, and that thrive off oxidized metals. This quickly lead to the realization that life could potentially exist in places such as Europa, and thus the search began.
(Image credit: NASA/JPL/Space Science Institute)
(via thedeadgypsygirl)
