• Question: If we can see some of the first ever galaxies that are no longer existent by pointing the Hubbell space telescope at a spot of sky for a lengthy time period, Is it possible that we could actually see the Big Bang if we pointed the Hubbell space telescope at the same position for an even longer period of time?

    Asked by yourmum to Meeks, Pete, Stephen, Steve, Tom on 22 Jun 2010 in Categories: .
    • Photo: Stephen Curry

      Stephen Curry answered on 18 Jun 2010:

      Hi yourmum,

      Gosh , great question – quite a conundrum. I’m guessing a bit here but assuming (i) the big bang didn’t last very long and (ii) the matter of the universe expanded outwards at less than the speed of light, I would say that the light quickly outruns the matter so that we can no longer see it.

      However, there is a flaw in my argument. If the light outruns the expansion of the universe, where does it go (assuming that created in the big bang were all of known space and time).

      And now my head hurts – I think I’m going to have to lie down…

      (More seriously though , I’ve never heard of anyone suggesting this would be possible. I do know that scientists have measured the cosmic background radiation, which is the ‘after-glow’ of the big bang. So while we may be able to detect its remnants, this would suggest that we have missed the man event)

    • Photo: Tom Hartley

      Tom Hartley answered on 20 Jun 2010:

      Again I am no expert, but my understanding is that you can detect a faint glow from just after the big bang in the microwave spectrum (very stretched out).

      Cosmologists can use these observations to figure out what shape (and how “lumpy”) the universe was when it was first formed, which will help explain why it is the way it is today (with clumps of stars, galaxies etc.).

      http://en.wikipedia.org/wiki/Cosmic_microwave_background_radiation

    • Photo: Pete Edwards

      Pete Edwards answered on 20 Jun 2010:

      Great question.
      It turns out that if we had a telescope that was infinitely powerful we would actually see just darkness.
      Most cosmologists believe that our universe began in the big bang an incredibly hot ‘soup’ of particles and high energy radiation. The universe began to cool, and it wasn’t until 380,000 years later that it was cool enough for stable gas atoms to form. At this time there was no visible light in the universe for any telescope to see.
      This period is called the cosmic dark ages – stars had yet to form and there was nothing shining and giving out light. It was only when the first stars formed from the cool gas that the universe lit up. This was around 500,000 years after the big bang.
      So an infinitely powerful telescope would reveal fewer and fewer galaxies until the universe goes dark. We are already starting to see this happening with some of the images from the best telescopes we have today.

    • Photo: Marieke Navin

      Marieke Navin answered on 22 Jun 2010:

      What a fab question. We can’t see all the way back to the Big Bang, but we can see back to 300,000 years *after* the Big Bang – we have a picture of the Universe at this time. It’s called the microwave background. You know when your TV isn’t tuned in and you get the black and white snow? Well a few % of those photons are from this background – isn’t that amazing? We can’t see back before that time because before this time light couldn’t escape.

    • Photo: Steve Roser

      Steve Roser answered on 22 Jun 2010:

      ….well we can see something called fossil radiation that seems to have been around for a very long time – if the speed of light is constant, and the age of the universe is 14biliion years, then we are looking for stuff, roughly that distance away…thats pretty tough!

Comments

  • Photo: yourmum

    yourmum commented on :

    Yes but stephen, cant we see galaxies that are no longer existent through the hubble telescope?

  • Photo: yourmum

    yourmum commented on :

    or is that just as you said about the big bang, an ‘afterglow’?

  • Photo: Stephen

    Stephen commented on :

    I believe that’s right, youmum, we can’t certainly see very far back in time to things that no longer exist because the light took so long to reach us.

    But the Big Bang was the very first visible event in the history of the universe (as far as we know – let’s leave aside what went on before that). I’m guessing that it’s simply too far back for us to have seen it – in other words the light waves reporting on this event have already passed us by.

    But I could be wrong!