• Question: Could an organism (Specifically an extraterrestrial) survive on something that isn't water? I have been thinking about how a lot of scientists state water is the building blocks of life, but what if the building blocks for life on another planet were different, and they survived on a different abundant element, possably a type of sulphuric acid or otherwise. Water seems to be the required element for life on earth, so evolution could have created some ingenious creatures on other planets (If they exist)

    Asked by danm36 to Hywel, Joseph, Patience, Poonam, Rachael on 20 Jun 2010 in Categories: .
    • Photo: Poonam Kaushik

      Poonam Kaushik answered on 18 Jun 2010:


      So far dear! no extraterrestrial life has been observed though predicted. Whatever knowledge we have today is based on life existing on earth. And so is the scenario on earth that no life can exist without water. If we do not have any experience of extraterrestrial life plus any evidence how can we predict anything !!!

    • Photo: Joseph Cook

      Joseph Cook answered on 19 Jun 2010:


      Water is important for life on Earth, but you’re right – life on other planets may have evolved under different conditions and may have different needs. It’s doubtful that sulphuric acid would be a necessary element as it is quite a harsh substance and would probably be very harsh in other atmospheres as well.

      If life exists on other planets, then it’s very likely that it’s a very long away from here and we may never reach them.

    • Photo: Dr Hywel Jones

      Dr Hywel Jones answered on 20 Jun 2010:


      You are right that water appears to play a vital role for life on earth, as does oxygen, carbon and sunlight. However, deep in the see there are organisms that do not rely on the presence of oxygen or sunlight and use sulphur and heat emitted from sub-sea volcanic vents to sustain life (although of course water is still important for these creatures). Also there are plenty of desert life forms that survive in the presence of very little water.
      There is therefore no real reason to think that water is absolutely necessary although I’m not aware of there being any water free life on earth (I could be wrong).
      So there is no evidence of such life and life on other planets has not yet been detected although big efforts are on-going with respect to Mars. Of course these searches all rely on the idea of water being present on Mars at some stage to sustain life as we understand it.
      But of course you are correct in the fact that there is the possibility that life elsewhere may have evolved to be independent of water, although, as I say above, we have no evidence of its existence.

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