• Question: is there life out there...

    Asked by 282spaa47 to Heather, Helen, Hugh, Jane, Julian on 7 Nov 2014. This question was also asked by CherLouise, Harry payton 657, Jasmin, Meganthemarsbar, 425spaa38, OneDirection, maisie374, Talan007, TJJohnson, Oliver Johns, DaisyB123, ConnorM, FelicityP, ollie.t, Dom.H, jess.i.am, Befney, BethanyGSAWRUS, Amazing person called Aston Martin, Chrissypops, Emily_Luisa_Taylor, Will Hallett :-), myles from LIDL, mini me.
    • Photo: Julian Onions

      Julian Onions answered on 7 Nov 2014:

      I think almost certainly.
      If we look at the Earth, it was formed 4.5 billion years ago, but within 500 million years it appeared life had started, and this was on a very hot planet, bathed in ultra violet light (which would give anything on the surface REALLY bad sunburn) and was being bombarded with meteorites. However life still got started, and very quickly too.

      There are a 100 billion suns in our galaxy, and missions like Kepler have shown nearly all suns have planets around them, and some are very like our own. So if life can start on our own planet, its fairly likely it can start elsewhere.

      Intelligent life is a different matter. There are several barriers it has to go through, and whilst we are here today, many times in the history of the planet life could perhaps have shown intelligence, but didn’t. So maybe it’s a combination of things that needs to happen.
      A planet like our own, around a long lived star, not too far from it but not too close. Maybe a large moon to keep the seasons stable, and a few happy accidents along the way.
      With 100 billion stars in our galaxy, and maybe 1000 billion galaxies all with similar numbers of stars in them, it seems likely somewhere, the same set of circumstances will come together.

    • Photo: Hugh Osborn

      Hugh Osborn answered on 7 Nov 2014:

      Honestly – we don’t know. But we are looking.

      There are a few things we do know, though, and we can make a few educated guesses. Thanks to recent planet-hunting missions like Kepler, which I am lucky enough to work on, we know there are hundreds of billions of planets in our Galaxy. And we know there are hundreds of billions of galaxies just like ours in the patch of the universe we can see. We also know that life found a way to get started on at least one of those planets; Earth. So it seems likely that there would be life on other worlds as well.

      In fact, there’s a really simple and interesting (honest) equation you can use to guess the number of alien civilisations that might be in our galaxy alone. That’s called the Drake Equation and the best guesses show that there’s a load of civilisations like ours out there waiting to be discovered. (BBC piece on the Drake Equation: http://www.bbc.co.uk/guides/zqdbgk7#z3yx6sg )

    • Photo: Jane MacArthur

      Jane MacArthur answered on 7 Nov 2014:

      The Drake Equation was constructed partly in answer to the “Fermi Paradox”, whereby Enrico Fermi asked, given we know there are billions of stars, many older than our Sun, and some will have Earth-like planets, if the Earth is typical then other planets should have developed intelligent life and eventually interstellar travel, and should have colonised the galaxy by now – so why haven’t we seen them?

      The “Great Filter” is another interesting theory: “With no evidence of intelligent life other than ourselves, it appears that the process of starting with a star and ending with “advanced explosive lasting life” must be unlikely. At least one of the steps must be improbable. If it’s not an early step (i.e., in our past), then the implication is that the improbable step lies in our future and our prospects of reaching interstellar colonization are still bleak.” (http://en.wikipedia.org/wiki/Great_Filter)

      Although life got started on Earth about 3.8 billion years ago, as single-celled bacteria, these didn’t evolve to multi-cellular organisms for a further 1.7 billion years (2.1 billion years ago), with the first familiar life such as fish, plants and forests developing at a mere 0.5 billion years. Many people think the evolutionary break through from bacteria to multi-cellular organisms could be one of the improbable steps against intelligence life developing, per the Great Filter theory.

      Astrobiology is a fascinating new field exploring the possibilities and conditions needed for life, and in particular investigating “extremophiles”, organisms that can live in extreme high/low temperatures and pressures, and extremes of acidic/alkali.

    • Photo: Helen Johnson

      Helen Johnson answered on 9 Nov 2014:

      I definitely think there is, somewhere. Like the others have said, there are billions of other galaxies out there, with billions of stars, and lots of those stars have planets.
      Planet hunting missions like Hugh works on are really exciting, we’ve already found thousands of different worlds and maybe it won’t be so long before we find candidates that we seriously think could host life, in the so called ‘Goldilocks zone’ of a solar system – where it’s not too hot, not too cold!
      One really exciting mission at the moment is Rosetta. A probe has been travelling for 10 years to reach comet 67P (they call it the rubber duck comet) and land on it! This video is brilliant, I love it – http://www.esa.int/spaceinvideos/Videos/2014/11/Once_upon_a_time_preparing_for_comet_landing
      Scientists think a comet might have been what first brought life to Earth…

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