• Question: Are there any other living things except us in the universe?

    Asked by anon-267480 on 5 Nov 2020. This question was also asked by anon-267455, anon-270887, anon-267551.
    • Photo: Zsolt Keszthelyi

      Zsolt Keszthelyi answered on 5 Nov 2020:

      There are two possible final answers (yes or no) and either would be quite dramatic. At present, the answer is that we simply don’t know.

      If you think about how many stars there are in the universe (more than the number of people on Earth, a really large number), and how many planets as well, then the puzzle pieces put together would make it look like that life could be present elsewhere. The ingredients are given. But we don’t fully know how difficult some steps of evolution are so it is not easy to say what would happen if there were planets out there that looked just like Earth.

    • Photo: Julian Onions

      Julian Onions answered on 5 Nov 2020:

      Maybe! We don’t really know although we are looking hard. Mars, Venus, the Moons of Jupiter and Saturn, and planets around others stars are all being studied. So far nothing definite has been found.

    • Photo: Daisy Shearer

      Daisy Shearer answered on 5 Nov 2020:

      We don’t know for sure is the honest answer. There are lots of scientists studying Earth-like exoplanets which could be inhabitable. There are also people investigating other kinds of life, like bacteria, on planets like Mars and Venus which are closer to home. We won’t know for sure until we have sufficient evidence though.

    • Photo: Adrien Chauvet

      Adrien Chauvet answered on 6 Nov 2020:

      In our search for extraterrestrial life, we are usually looking for “signatures” of life.
      As we know it, life requires liquid water and is composed mostly of carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur (CHNOPS).
      Hence, that is what we are looking for: traces of liquid water and of these elements in specific proportions.
      And because the closest known exoplanet (earth-like planet) is so far unreachable, all we can look at are the spectral signature of these elements (through the way they interact with the light that the near by star emits). It is far from trivial, and so far, as others have said, we have not found anything substantial.

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