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Life on Mars

Updated Friday, 14th December 2012
What happens if we find evidence of life on Mars? 

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Curiosity Mars Rover NASA's Curiosity Rover

Discover how asteroids and microbes flying through space could hold the secret to life on Earth and Mars in this animated video.

The ill-fated Beagle2 lander (see link below) which was led by a consortium from the Open University and was lost on its way down to the planet had some instruments to detect the chemical and isotopic effects of life on the martian environment.

More recent, and successful, landers have been rovers whose job is to seek out the places that could support life, or at least that could have supported life in the past. NASA’s Curiosity Rover landed on 6 August 2012 in Gale crater. This was chosen from a shortlist of several sites offering access to layers of martian sediment that had been deposited over a long time period, and thus expected to preserve evidence of how surface conditions have changed over billions of years. That makes for a fascinating geological journey, whether or not life ever occurred there.

Currently we know of at least two other worlds in our Solar System where life could exist – Mars and Jupiter’s satellite Europa. It has also become clear that most of the stars in our Galaxy may have their own planets. If conditions suitable for life occur on only a small fraction of those, that is still a vast number of potential habitats.

So, are we alone, or not? We don’t know how common it is for life to get started: some scientists think that it is inevitable, given the right conditions. Others regard it as an extremely rare event. If we were to find present or past life on Mars, then provided we could rule out natural cross-contamination by local meteorites, this evidence of life starting twice in one Solar System would make it virtually unthinkable that it had not started among numerous planets of other stars too.

Based on what we know today, Earth could be the only life-bearing planet in the Galaxy, but if we find life on Mars that is not related to life on Earth, then life, and probably intelligence, is surely abundant everywhere. As the visionary Arthur C Clarke put it: “Two possibilities exist: Either we are alone in the Universe or we are not. Both are equally terrifying.”  Mars may not hold the key, but it surely holds one of the numbers of the combination-lock. 

Question: How would your outlook on humanity’s place in the cosmos change if we knew for sure that there was life, maybe even intelligent life, on the planets of other stars? Share your answers using our Comments facility. 

Find out more about astronomy and planetary science at the Open University: 


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