Astrobiology

Mars, the fourth planet from the Sun, is currently undergoing a great deal of investigation concerning its capacity for maintaining life.

A biosignature, a substance that provides scientific evidence of past or present life, is present in the form of fog on the planet Mars.

Terraforming Mars is the hypothetical idea that Mars could be altered in such a way to sustain human and terrestrial life forms.

Europa, one of Jupiter's four moons, is covered by a layer of ice/water and scientists have multiple hypotheses to explain its structure.