• Question: Are We Alone In the Universe?

    Asked by alanah to Cathal, Ciara, Emma, Michael, Sive on 14 Nov 2013.
    • Photo: Sive Finlay

      Sive Finlay answered on 14 Nov 2013:

      Hi Alana,
      I don’t think so! The universe is so enormous that there are bound to be some galaxies very similar to ours with planets that have conditions suitable for life. However, the type of life that’s out there probably doesn’t look like the little green aliens we see in films. All life on our planet is carbon-based but elsewhere in the universe there might be living things made of silicon or some other element.
      So I don’t think we’re alone but I do think it’s unlikely that we’ll bump into any alien space craft any time soon!
      Sive

    • Photo: Michael Nolan

      Michael Nolan answered on 14 Nov 2013:

      Hi again Alanah,

      nice question and very topical with results from Kepler in recent times.

      20 years ago we had no way to find extra-solar planets (that is outside our solar system), now with Kepler in particular we have made great leaps forward.

      We think we know what conditions are needed for a planet to be favourable to life like our own carbon based life and now we can go hunting for such planets.

      Of course, even if we find something like earth there are other possibilities
      (1) life has yet to start on that planet
      (2) life did start, but has remained single celled
      (3) there was life but it was rendered extinct
      (4) there was life, but it destroyed itself
      and more…

      Also, there could be other ways of generating life, based on say, liquid metals (who knows!) or hydrogen metal (crazy form of hydrogen!).

      Given that there are around 1000000000000000000000000 stars in the Universe (answer to another question), then if even only one-billionth of them have habitable planets, that still means 100000000000000 planets with life – life could be everywhere, but separated by vast distances so that communication will be very difficult (speed of light being the main culprit).

      If you are asking about there being other life in the universe in general, then the answer is most definitely we are NOT alone, and we will find evidence for that on Mars (at least in for the past). It may be that 99.99% of life is single celled, but its still life.

      If you mean if there is other intelligent, conscious life like us, then it is hard to be definite, but I would say WE ARE NOT ALONE and we have simply not encountered them yet and the distance to be traveled to the nearest system with life will be immense, so we are, day-to-day, unfortunately, alone in the universe.

      See how far Voyager has gone in 35 years – just the edge of the solar system or 0.002% of a light year, with 200,000 years to get to the nearest start with habitable planets; homo sapiens is around maybe 20,000 years. So communication with neighbours may be tricky

      This does make my head spin when I think about it!!

      M

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