• Question: How were we created after the Big Bang

    Asked by anon-267414 on 5 Nov 2020.
    • Photo: Zsolt Keszthelyi

      Zsolt Keszthelyi answered on 5 Nov 2020:

      I will outline some points in terms of the Astronomy part and let a Biologist comment on the evolution aspect.

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      The Big Bang created hydrogen and helium, and some very fragile light elements (such as some lithium, for example). All other elements were not present initially. Then, stars were formed and these stars were powered by nuclear fusion, a process in which heavier elements were created.
      These elements were recycled after the first stars finished their lives. So the second “generation” of stars already had some elements other than only hydrogen and helium, but not much. These stars also fused elements to remain stable and shine. So they could create more elements. In the present-day Universe, when stars and planets form, they contain this material.

      This allows us to have carbon, oxygen, and iron (and so on), which are all essential for life as we know it. So, luckily, the Universe is old enough that these elements were available when the Sun and Earth formed. Once the Earth was formed from gas and dust, the first species are thought to appear “shortly” after.

      From these first species, humans could evolve over a rather long period of time.

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    • Photo: Sam Geen

      Sam Geen answered on 6 Nov 2020:

      This is a really complicated question! Carl Sagan said: “If you wish to make apple pie from scratch, you must first create the universe” – like Zsolt says, you need the right atomic elements, which you need stars and supernovae to make, you need planets to form, and planets that life can live on (this is very hard to do!), and you need a long time for life itself to evolve from simple chemicals. Life is really amazing and we still don’t really know how much life is out there in the universe. The future of looking for life in space is very exciting, and people are still finding out new things about distant planets where life might be found.

    • Photo: Daisy Shearer

      Daisy Shearer answered on 8 Nov 2020:

      Great question! This is really complicated and in the realm of cosmology (which isn’t my area of expertise!). Basically, we think that after the big bang various particles formed to make elements which made the stars and planets. Eventually, life started on Earth and we evolved. This is such a complicated area that covers the entire history of the universe so there are many people working on answering this question as we speak!

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