• Question: is there such things as aliens?

    Asked by to Laurence, Greig, Dave, Chris, Aimee on 19 Jun 2014. This question was also asked by .
    • Photo: Laurence Perreault Levasseur

      Laurence Perreault Levasseur answered on 19 Jun 2014:

      We haven’t found any other living organism anywhere on other planets of the solar system yet. But really we are just starting to explore the other planets and their moons around our own sun. The only one we really have explored in details is Mars, and we haven’t found yet any evidence of life over there. At the moment, there is a NASA rover called Curiosity on the surface of Mars, looking for traces of life.

      Apart from Mars, there are few moons of Jupiter that could be good candidates for life:
      -Europa (it’s covered in ice, but under there is huge oceans of liquid water and there is volcanic activity – so heat, both essential for life)
      -Io (it has an atmosphere and a lot of volcanic activity – again good for the heat, and very interesting chemical elements for life)

      and moons of Saturn:
      -Titan (it’s pretty cold over there, but it looks like it could have hosted life in the past, due to some of the elements found in it’s atmosphere)
      -Enceladus (it’s very warm because it looks like it’s core is made of molten rock, and at the surface it’s covered in water ice, under which there are oceans. It also has all the elements essential for life)

      Note that here, we are talking about life in the form of microbes or very simple organisms, not big, human-like E.T. That, we are pretty sure, doesn’t exist in our own solar system.

      Outside our own solar system, we are starting to find more and more planets orbiting other stars (currently we estimate there are about 8.8 billions of habitable, Earth-size planets only in our own galaxy, the Milky Way, and there are billions and billions of galaxies in the Universe!!). So that means chances are very high that life exists somewhere else.

      To quote a movie from the 90s, ‘if it’s just us… seems like an awful waste of space. Right?’

    • Photo: Dave Jones

      Dave Jones answered on 20 Jun 2014:

      We haven’t found life on any planet other than the Earth… yet. But, that doesn’t mean that there aren’t any aliens. Aliens would be difficult to find. You have to think about how you would detect aliens if they were on another planet, and maybe the best way to think about that is to consider how aliens would detect us. How would they notice us? Probably from all the radio waves we emit into space (from our TV antennae, from radio antennae, communications, everything!). But, just as we know with our mobile phones that signal doesn’t always travel so far (I hate it when I can’t get a signal on my mobile, don’t you?). So, they’d probably need to be quite close (in astronomical terms, which means inside our Galaxy at least). Even more difficult we have to think about how long we’ve been producing radio waves, we only started with radio and tv etc. in the last hundred years or so, meaning that those radio waves can only have travelled about a hundred lightyears and so only aliens within one hundred lightyears of us will have picked up our radio signals. That really reduces the number of planets where they might have seen us!

      So, if we think about the same thing for aliens, we’d also only be able to notice them on a very small fraction of the planets out there and there are a lot of planets! So, maybe there are aliens, just we have had no chance of finding them so far!

    • Photo: Aimee Hopper

      Aimee Hopper answered on 21 Jun 2014:

      I would find it hard to accept that aliens dont exist. I am a strong believer that we are not the only planet with life in the universe – it seems far too unlikely. Though I have no idea why 1) we haven’t found any other forms of life yet 2) why other life hasn’t found us and 3) if other life is out there, whether we are ready as a race to accept it.
      We cant even get along with our own race, so maybe other life forms are avoiding us…

    • Photo: Greig Cowan

      Greig Cowan answered on 23 Jun 2014:

      At this point, we just don’t know. Life has only been observed on Earth, but given the large number of stars and planets that we have seen outside of our solar system, there must be a good chance that at least one of them has conditions suitable to life (have a read about something called the Drake equation). Even within our solar system we know there are some moons of Jupiter and Saturn that are covered in ice, indicating that there may be liquid water beneath them. These moons are cold, but due to their proximity to the gas giant planets, there are large gravitational forces acting on them. We believe this keeps the core of the moons warm enough that there really is liquid water below the surface that could give an environment for life to exist.
      I hope we send some probes to these moons soon so that we can find out! After that, our next step should be looking at planets outside of the solar system 🙂

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