• Question: are there any living species on other planets

    Asked by to Laurence, Greig, Dave, Chris, Aimee on 16 Jun 2014. This question was also asked by .
    • Photo: Laurence Perreault Levasseur

      Laurence Perreault Levasseur answered on 16 Jun 2014:

      Short answer: we don’t know.

      Long answer:
      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. You can check out daily updates and pictures here:
      http://www.nasa.gov/mission_pages/msl/#.U57fF43V_O8

      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: Greig Cowan

      Greig Cowan answered on 16 Jun 2014:

      I hope so! I think finding evidence of life on other planets would be one of the greatest discoveries that we have ever made. However, at the moment we don’t have any indication that such life exists. There are a few interesting places in our own solar system where we should try and look for life before trying to go beyond our system. In particular, the moons of Jupiter and Saturn look very promising as we have already made observations using satellites and probes that shown that some of these have liquid oceans beneath their surfaces. Hopefully we send up some robotic mission to these moons soon. There is also the possibility of using telescopic observations of other stars to study the light that comes from exo-planets. However, this is a new and exciting field so it is not clear if we will be able to infer the presence of life from these observations.

      Have you heard of the Drake equation? This is the equation that allows people to play with the idea of life on other planets. One of the questions it raises is “where is everyone else?”.

    • Photo: Dave Jones

      Dave Jones answered on 16 Jun 2014:

      So far we haven’t found any! But, that could just be because it’s really difficult. For example, we could think about whether aliens would know about 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 16 Jun 2014:

      I’d certainly like to think so – hydrocarbons (chains of hydrogen, carbon and oxygen) have definately been found on other planets, the these are the building blocks of life. We just need to find a planet close enough to us to see if the right conditions are on the planet too…

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