ExoMars 2016 launches

We're sending another probe to Mars! But why are we going back?
20 March 2016

Interview with 

Ben Pilgrim, Cambridge University


The ExoMars 2016 probe launched successfully last week. This mission aims to seek out methane, which could be a crucial clue to whether there is life on the red planet, as Ben Pilgrim explained...

Ben - The European Space Agency launched the ExoMars probe recently and this is the latest in a series of probes to go to Mars and it's going to look for methane.  It's going to look for methane in a search for life on Mars. 

This has been one of the biggest scientific question for hundreds of years actually, and if life on Mars were discovered it would certainly be one of the biggest scientific discoveries ever.  Now, why methane is important is, if you think about Earth, most methane on Earth is produced by living things. A process called methanogenesis; this is where, if you imagine a swamp or somewhere like this or a rubbish tip, there's not much oxygen, we get bacteria breaking down carbon-based products and they produce methane and they use this anaerobic respiration process to produce their energy. 

Now, methane in the atmosphere doesn't last very long; the radiation coming from the Sun in the Earth's atmosphere can generate single oxygen, then we get these hydro radicals and this breaks down methane.  So atmospheric methane doesn't last very long so, if it's present, it had to have been generated reasonably recently and a couple of probes that have been to Mars in the last ten years or so, detected the presence of small amounts of methane.  So there is methane in the martian atmosphere and then the question is, well how did it get there. 

There are other processes that can produce methane in the atmosphere other than living things. It can come from volcanic activity or it can also come from the action of, again, strong sun radiation on organic compounds that might have got there on meteorites or something like that. 

So, the presence of methane doesn't suggest life in itself, but this probe has gone to look at it in more detail. It has instruments on it that will be able to detect, perhaps, what other gases are present to give us an idea on the source of the methane and also to look at, more specifically, the isotope composition in methane which will, again, help to track down its origin.


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