• Question: how did the first living thing existed on planet earth and why did it only existed on planet earth why didn't it existed in other planet

    Asked by 477gdna29 to Arthur, Clare, Daniel, David, Tora on 10 Nov 2014. This question was also asked by mr brightside.
    • Photo: Clare Harding

      Clare Harding answered on 10 Nov 2014:

      Wow, these are hard questions!

      So the current theory is first there was chemistry and some chemicals managed to create reactions which could keep themselves going. These got more and more complex until gradually, what we could recognize as life developed. This probably happened a few different times in different places on Earth but it took a long time, millions of years at least.

      Personally, I think life probably does exist on other planets. I have no idea if intelligent life like us does but I think at least single cells will exist in other places in the universe. And if we could find even a single, living cell that evolved somewhere other than earth it would be one of the most exciting things ever to happen in science and it would help answer a lot of really interesting questions about why we evolved the way we did!

    • Photo: Daniel Parsons

      Daniel Parsons answered on 10 Nov 2014:

      Right now, life as we know it would not survive anywhere except Earth or Mars, and possibly Europa (a moon of Jupiter in our solar system).

      Areas of Mars near its equator get above freezing for parts of the year, and while the Martian atmosphere is too thin to sustain liquid water on the surface, the pressure is great enough underground, and muddy slurries of landslides from subsurface water have been observed. So there might be life hidden away on Mars.

      On Europa we know that there is mud some hundreds of kilometres below the ice that will have water in it, so there might be life there too.

      Earth of course has oceans of water and so lots of life.

      Now the answer above is about there here and now….but how did we get here. Well, it is all a matter of TIME. On Earth, we have had liquid water, energy and the right chemical mix to sustain life for a very, very, long time. This means that evolution from the simplest little bugs right through to us has had the time to happen. Elsewhere, its not the same. Mars for example lost its atmosphere a long time ago.

    • Photo: Arthur Dyer

      Arthur Dyer answered on 10 Nov 2014:

      Hi there,

      Good question and one we still don’t 100% know the answer to.

      one of the current theories is that there were little molecules that learned to use the heat and light from the sun to make energy and that this meant they could grow really well. Because they could get extra energy from the sun (like plants do today) they could grow bigger and stronger than other things around them.
      From this evolution started so the cells that had strong walls were more protected so they grew better then the cells that learned to work together grew faster and stronger so there were more of them and bit by bit life evolved into what we see today.

      As for why there isn’t life (that we have found!) on other planets it’s thought to be because of something called the Goldilocks Theory. Basically our planet is just in the right place. If it were nearer to the sun it would be too hot (like venus) and if it were too far away from the sun it would be too cold (like jupiter) but where it is now it’s just right (like the porridge in Goldilocks!)

      If there is another planet circling another star in just the right position then i’m sure there’s some kind of life there too.

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