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Author Topic: Can we see out of the universe?  (Read 284 times)

Offline thedoc

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Can we see out of the universe?
« on: 15/08/2016 13:53:01 »
Jon  asked the Naked Scientists:
   I listened to your podcast with interest this week.  One speaker said
that once you cross the event horizon of a black hole, you can no longer
see out of the black hole.  I believe he got it wrong.  Observers from
outside the event horizon can no longer see you once you cross the event
horizon, but you can certainly see out.  In fact, enormous amounts of
light (and particles) will come crashing down on you. Where does the truth lie? Can we see  out of the black hole?




   
What do you think?
« Last Edit: 15/08/2016 13:53:01 by _system »


 

Offline Ethos_

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Re: Can we see out of the universe?
« Reply #1 on: 16/08/2016 01:27:52 »
Jon  asked the Naked Scientists:
   I listened to your podcast with interest this week.  One speaker said
that once you cross the event horizon of a black hole, you can no longer
see out of the black hole.  I believe he got it wrong.  Observers from
outside the event horizon can no longer see you once you cross the event
horizon, but you can certainly see out.  In fact, enormous amounts of
light (and particles) will come crashing down on you. Where does the truth lie? Can we see  out of the black hole?




   
What do you think?
Because no one has yet made that trip, our certainty about this question is somewhat limited. Bearing this in mind, take my answer with a grain of salt.

Firstly, from your title; "Can we see out of the universe?" may not be the same scenario as your secondary thoughts about looking out of a black hole. While there are similarities between our universe and a black hole, we can't assume they are the same, and may not in truth even be that similar.

Secondly, for us to see out of our Universe, there would necessarily need to be something outside to see. And with the distances involved, even if there were, we might never have opportunity to view them because of expansion. And many theorists also believe that there is nothing outside to see because the universe is closed.

Thirdly, the question about black holes is an interesting one. Current theory suggests that anything falling into a black will be red shifted to the extreme and the image of the falling object will be forever frozen upon the surface of the event horizon. Note; This is only current theory and as yet, we have no observable evidence.

Fourthly, seeing out of a black hole would in my opinion be as you have speculated. In fact, current belief suggests that not only could someone see out, but they would see the rest of the universe pass from present into the far future in a matter of a split second. This possibility is, of course, if they had enough time to turn and look back before they were spaghetti-fied.


So what would they view from this vantage point? Depends upon how the universe dies and how long it would take. If heat death is the end, they will see everything go very dark very quickly. If the universe collapses into another Big Bang, they will witness the fire and glow of it's rebirth.

This is of course mere speculation, we just don't have enough information yet to be certain about these questions but it is fun none the less to surmise isn't it?
« Last Edit: 16/08/2016 01:40:48 by Ethos_ »
 

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Re: Can we see out of the universe?
« Reply #1 on: 16/08/2016 01:27:52 »

 

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