• Question: who discovered the whole thing about the big bang?

    Asked by Elyse and Yukta to David, Dawn on 23 Jun 2016.
    • Photo: Dawn Lau

      Dawn Lau answered on 23 Jun 2016:

      I would say that the big bang theory has a lot of scientists that contributed to its explanation. I’ll try and do this answer justice as a non-expert.

      The idea behind the Big Bang seems to have been first proposed by Georges Lemaître, when he suggested that the universe could have originated from a single point. Using Einstein’s equations of general relativity, a mathematician called Alexander Friedmann also showed that the universe could be expanding. Supporting evidence came from Edwin Hubble, who noticed that galaxies were moving away from our planet in all directions, and that the speed at which they were moving away was proportional to their distance. This implies that the universe used to be smaller and denser.

      From then onwards, the discovery of cosmic microwave background radiation (which is kind of the leftover hot temperature from the big bang) and subsequent refinements of this observation cemented the big bang theory as the most rational theory of the universe’s starting point.

      So in short: I guess you could say a couple of dudes suggested the big bang theory, and many other people subsequently found evidence to support it.

    • Photo: David Robertson

      David Robertson answered on 24 Jun 2016:

      Good answer by Dawn.

      The idea started as just that, an idea. The key evidence was Hubble’s observations that all galaxies were moving away from each other, and the further away they were the faster they were going. If you run this idea backwards then everything collides at some point. It was such a strange idea that this was not enough to convince everyone. The next strong piece of evidence was the discovery of the cosmic microwave background by Arno Penzias and Robert Wilson. These guys were trying to build a super-sensitive radio detector and pointed their instrument at an empty bit of sky where they thought they shouldn’t see anything, but kept seeing a small signal. After months of investigation (including cleaning bird poo out of their antenna) they reported their results, and cosmologists got extremely excited as this was exactly what they had predicted from the big bang theory, but had not thought that anyone would be able to detect.

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