• Question: Is there life on other planets?

    Asked by samuelharrison to Alex, Amy, Andy, Georgia, Ollie on 21 Jun 2011.
    • Photo: Andy MacLeod

      Andy MacLeod answered on 18 Jun 2011:

      No one knows. Yet.

      Hello again Samuel. The universe is pretty big, so the chance of there being another planet out there capable of sustaining life is pretty high. It may not be life as we know it, but if life does exist elsewhere, we will certainly share some characteristics.

      An astronomer call Frank Drake once tried to put some concrete numbers to try and work out how many civilizations in the galaxy there might be capable of communicating with us. Given some assumptions about the stars in our galaxy, and the probability of life arising, Drake initially came up with a number of about 10 civilizations in our galaxy capable of communicating.

      But the final outcome depends on the values you assume for the numbers you put IN. The output can vary dramatically depending on your assumptions. If you want to try it yourself, there’s an online calculator here:

    • Photo: Georgia Campbell

      Georgia Campbell answered on 21 Jun 2011:

      We haven’t found life on other planets yet, but we have found a lot of evidence that there could be (of could have been, or could be in the future…) life on other planets. A lot of scientists work on atmospheric data, or surface samples, from other planets to try and work out what sort of life they could sustain.

      One of the most exciting recent discoveries has been right here on Earth though – scientists found a type of bacteria in a lake in california that partially builds its DNA from arsenic. Every other living creature on Earth uses phosphorous as the ‘backbone’ to build its DNA, and arsenic is poisonous to almost everything living thing we previously knew about too – so this means that DNA is more flexible in structure than we thought,and gives more scope for finding living organisms elsewhere! Pretty cool 🙂