Black Holes and Wormholes: Fact or Fiction?

[narrator]

Hi,

Lay questions again.

What's the real story - is a black hole potentially a worm hole?

If someone theoretically entered a black hole, the common portrayal is experiencing tremendous acceleration. But with time compression, how different would that acceleration feel to the traveler compared to what an observer would witness?

And would the acceleration still be a=F/m in m/s^2 ?
Does that change at any point during the journey?

Thanks

p.s. no, I don't have any travel plans...

 

[Ryan_m_b]

Any one getting close to a black hole will be ripped apart by tidal forces. If they are falling feet first the gravity pull on their feet will be greater than that on their head (this is true on Earth but would be much more pronounced closer to a black hole). The difference will be so great that they will be torn apart http://en.wikipedia.org/wiki/Spaghettification

Time dilation wouldn't be to much of an issue as that pertains to high velocity not high acceleration. Whilst a black hole might pull you in at high acceleration relativistic forces aren't going to make much of a difference.

Worm holes are completely different objects to black holes, they are also entirely speculative. There is no evidence that worm holes could exist (to exist they would require exotic matter with negative mass)

 

[Cosmo Novice]

Hi,

Lay questions again.

What's the real story - is a black hole potentially a worm hole?

If someone theoretically entered a black hole, the common portrayal is experiencing tremendous acceleration. But with time compression, how different would that acceleration feel to the traveler compared to what an observer would witness?

And would the acceleration still be a=F/m in m/s^2 ?
Does that change at any point during the journey?

Thanks

p.s. no, I don't have any travel plans...

Hello Narrator,

From my understanding (As you know I am layperson same as yourself) from the perspective of the observer the object would begin to slow as it approached the 'edge' of the Event Horizon, as it crosses the EH the light from the object will become increasingly redshifted (due to gravitational time dilation) and will eventually shift through the electromagnetic spectrum. This will 'appear' to take a very long period of time for the observer - some posters have suggested an infinite time although i do believe there to be a finite - albeit very long time to dissapearence.

From the perspective of the object crossing the edge of the EH then time will be subjectively a normal speed. (At this point both timefram references are actual and correct.) Some posters have argues that while the subjective observer still sees the object it is long since gone - I disagree with this as I think the object is still, just times are moving relative to gravitational time dilation.

Hope this helps and I am not off topic and as always corrections are most welcome.

 

[phinds]

From the perspective of the object crossing the edge of the EH then time will be subjectively a normal speed. (At this point both timefram references are actual and correct.) Some posters have argues that while the subjective observer still sees the object it is long since gone - I disagree with this as I think the object is still, just times are moving relative to gravitational time dilation.

Rather that tell us what you personally agree or disagree with it would be lots more helpful if you would cite references that support one theory or another. Please understand that I am not trying to be in any way rude here, but physics and math don't care what we think, so facts are useful, opinions less so.

 

[IsometricPion]

What's the real story - is a black hole potentially a worm hole?

If someone theoretically entered a black hole, the common portrayal is experiencing tremendous acceleration. But with time compression, how different would that acceleration feel to the traveler compared to what an observer would witness?

And would the acceleration still be a=F/m in m/s^2 ?
Does that change at any point during the journey?

There are two things of which I am aware that might lead one to think that a black hole could harbor a wormhole. One is that the fully extended schwarzschild (exterior) solution http://books.google.com/books?id=w4...ack hole Misner&pg=PA838#v=onepage&q&f=false" (so, conceivably, one could free fall through the center of the black hole and miss the singularity). Neither of these solutions is considered to be a good description of the inside of a black hole (since they are vacuum solutions and must, in order to be realistic, be matched to a solution inside the horizon that results from the collapse of a star).

If the person is free falling, he feels no acceleration (though, as mentioned by ryan_m_b, he still experience tidal forces so, spaghettification could be a problem).

For a http://en.wikipedia.org/wiki/Four-acceleration" (ref. equation 32.9c) time after he sees the nearest part of the (spherical) star reach a radius of ~3GM/c² from its center.

 

[narrator]

Thanks guys for your input, and the links.. all good reading, especially the spaghettification and force-acceleration links and the reference to SR.

Side note, there must be a lot of terms in this forum that the site spell-checker doesn't like.. lol

 

[Cosmo Novice]

Rather that tell us what you personally agree or disagree with it would be lots more helpful if you would cite references that support one theory or another. Please understand that I am not trying to be in any way rude here, but physics and math don't care what we think, so facts are useful, opinions less so.

That being the case I should probably limit my comemnts to this sit as my limited knowledge comes from posters on this site rather than scientific papers.

Not to worry - I will limit my posting.

Thanks

 

[phinds]

That being the case I should probably limit my comemnts to this sit as my limited knowledge comes from posters on this site rather than scientific papers.

Not to worry - I will limit my posting.

Thanks

I'm certainly not trying to get you to limit your postings. I think that rank amateurs such as us sometimes ask interesting questions and even when we ask about things lots of folks here already understand well, we sometimes stimulate an interesting discussion.