• Question: Can you explain the Big Bang Theory to me please?

    Asked by holdl004 to Ben, Jony, Katharine, Mark, Peter on 15 Nov 2011.
    • Photo: Ben Still

      Ben Still answered on 15 Nov 2011:

      The Big Bang was thought to be the birth of the Universe – an unimaginable amount of energy was squeezed into an infinitely small space suddenly exploded. To imagine it exploding like gunpowder is wrong because outside of the explosion nothing existed. The Big Bang didn’t only give birth to the raw materials to build the Universe but also time and space itself – even the idea of nothing didn’t exist before the Big Bang. Or so people think, there are theories in which another Universe existed before the Big Bang but the honest answer is we are not sure what happened in the first 0.000000000000000000000000000000000000000000001 seconds of the Universe, this is where we need the physics of the largest things in the Universe and the smallest things in the Universe to work together which right now they don’t.

    • Photo: Mark Basham

      Mark Basham answered on 15 Nov 2011:

      Great explanation from Ben, A lot of what’s known is due to experiments which are done at the big facilities like CERN

    • Photo: Katharine Schofield

      Katharine Schofield answered on 15 Nov 2011:

      Yep I think Ben’s summed it up there nicely too.
      There are a lot of astronomy obsevations that have led scientists to (generally) agree that the Big Bang theory is correct. One was Hubble’s observation that distant galaxies all seemed to be moving away, which means that the universe appears to be expanding. He did that by looking at the ‘redshift’ of the light coming from galaxies. Redshift happens when an object is moving away and the wavelength of the light appears to get stretched out, so it gets shifted to the red end of the spectrum. This is just the same effect as you get when an ambulance goes past at speed with it’s sirens on – the sound changes pitch because of the sounds waves getting bunched together as it comes towards you and stretched as it drives away. Hubble found that the further away the galaxy, the greater the redshift – so the further away they are, the faster they’re moving away. This observation of things moving apart meant that in the past things must have been closer together, all the way back to the Big Bang.

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