Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Universe=Black Hole?

  1. Nov 4, 2005 #1
    Now before i begin i want to say that i have no formal education regarding the nature of the universe or even any astrophysics it is merely a hobby, a point of interest for me but i started thinking of this recently and wanted a some opinions of it.
    So here goes.
    It is my basic understanding that the universe is expanding in all directions. That is to say that an observer in our solar system, on our planet will observe the stars in all and every direction to be travelling away from us. It is also my understanding that there are two schools of thought on this that this expansion is finite and will reverse and result in a 'Big Crunch' or that this expansion is infinite and we exist in a boundry less universe. Supposing the latter is true our observer on earth will observe the expansion in all directions for all of time.
    Now if we were to imagine an observer inside a black hole(bear with me) it can also be said that they would observe expansion of the black hole in all directions as it absorbs matter and radiation from the surrounding space. Now its assumed that time, space, and matter all break down within a black hole but there is no conclusive proof of this.
    Now imagine an observer outside our universe. The gravitational pull of our entire universe should be equal to the sum of all gravitational forces within this universe as Gravity is always attractive so there is no negative gravity to cancel any of it out. So, as light cannot escape from a black hole due to its gravitational pull, similarily light should be unable to escape from our universe due to its enormous gravitational pull. Now imagine one adds a mass to our universe. The observer can no longer see this mass, only feel its gravitational attraction added to the overall gravitational pull of the universe. The observer cannot confirm nor deny if any matter added to our universe is destroyed or not, just as we cannot summize the same from the addition of matter to a Black hole.
    Is it then a step too far to say our universe behaves similarily to a black hole when observed from outside. We cannot say whether there is a limit to the expansion of either our universe or a black hole. So perhaps it can be deduced that a black hole is a small boundry less universe and that we are in effect inside a blackl hole. If this was the case perhaps each black hole within our universe contains matter which it has absorbed which has regions which are denser and slower than others and which are collapsing and spinning faster and faster until disklike galaxies are formed. Also outwardly perhaps our universe is just a black hole within another universe which is a black hole within another universe and so on and on and on...
    So perhaps there was no 'Big Bang' just a sort of 'Big Sak' of whatever matter or radiation came within range of our densely packed recently collapsed star. As we began absorbing so we began expanding and this cintinues even now.
    Of course as i say i have no education in this field nor am i well read on the subject but i feel if i have understood what little i have read (and there is a very very large chance i have completely misunderstood all of it) then this is't a very far-fetched idea. I am aware that there are no answers to all these Big questions and that many people suggest that black holes may contain some form of tunnel to another universe or something equally science-fictiony but i just thought i'd see what other people have to say on the matter. Please feel free to absolutely demolish my ideas and rip apart my limited knowledge on the subject it probably won't take very much for all this to completely fall apart.
  2. jcsd
  3. Nov 4, 2005 #2
    I think this idea is presented in Lee SMolin's bookThe Life of the Cosmos . He argues that natural selection accounts for the apparent fine-tuning of the physical constants leading to carbon based life because such constants also lead to the formation of universes having a large numbers of black holes. For this to be the case the 'laws of physics' must be passed on (with minor mutations) through the window of each new black hole. I'm still reading this particular book so I warn you that I may be missing something.
  4. Nov 4, 2005 #3
    Sounds interesting. I'll check it out. Thanks.
  5. Nov 4, 2005 #4
    Just a few comments :

    Yes its entirely possible that our part of the universe is a giant black hole.

    But I don't see how the mechanism "as we began absorbing so we began expanding" can work?

Share this great discussion with others via Reddit, Google+, Twitter, or Facebook