NASA’s Curiosity Rover takes a selfie on Mars in June 2018. Image via NASA/JPL-Caltech/MSSS.
By Gareth Dorrian, University of Birmingham
The Earth’s biosphere contains all the known ingredients necessary for life as we know it. Broadly speaking these are: liquid water, at least one source of energy, and an inventory of biologically useful elements and molecules.
But the recent discovery of possibly biogenic phosphine in the clouds of Venus reminds us that at least some of these ingredients exist elsewhere in the solar system too. So where are the other most promising locations for extraterrestrial life?
Mars is one of the most Earth-like worlds in the solar system. It has a 24.5-hour day, polar ice caps that expand and contract with the seasons, and a large array of surface features that were sculpted by water during the planet’s history.
Mars has polar ice caps. Image via ESA & MPS for OSIRIS Team/ MPS/ UPD/ LAM/ IAA/ RSSD/ INTA/ UPM/ DASP/ IDA)
The detection of a lake beneath the southern polar ice cap and methane in the Martian atmosphere (which varies with the seasons and even the time of day) make Mars a very interesting candidate for life. Methane is ...