Space Sciences Black holes: what are your thoughts?

[Blobbenstein]

The train will never fit entirely inside the tunnel and the bomb should never go off.

but the bombs sensors are not travelling with the train, so what the perspective of people on the train is, is irrelevant to whether the bomb would go off.

People in different reference frames see things differently.

 

[das_nut]

but the bombs sensors are not travelling with the train, so what the perspective of people on the train is, is irrelevant to whether the bomb would go off.

People in different reference frames see things differently.

Relativity is weird.

Next week, we should cover quantum entanglement.

 

[nog]

but the bombs sensors are not travelling with the train, so what the perspective of people on the train is, is irrelevant to whether the bomb would go off.

No, it's not irrelevant, the bomb still goes off in both points of view. They still see events unfold, they're not somehow set apart completely. What it shows is that simultaneity is based on perspective.

To put it another way, whether the bomb is moving or not, it's programmed to explode when certain conditions are met and should be explainable regardless of the point of view. This is entirely explainable whether the bomb is moving or not. It's actually rather elegant and counter intuitive. Well for me.

To relate it back to my original point, you can't simply disregard a perspective because you want to, not unlike the case with the black hole. The perspectives must be explainable or one arrives at a paradox (or an apparent one). You cannot simply will away one as irrelevant.

People in different reference frames see things differently.

Clearly.

Perhaps for distant observers they never see a black hole, but for those falling in, a black hole exists.

 

[nog]

Relativity is weird.

Next week, we should cover quantum entanglement.

I don't get it.

 

[Blobbenstein]

No, it's not irrelevant, the bomb still goes off in both points of view. They still see events unfold, they're not somehow set apart completely. What it shows is that simultaneity is based on perspective.

To put it another way, whether the bomb is moving or not, it's programmed to explode when certain conditions are met and should be explainable regardless of the point of view. This is entirely explainable whether the bomb is moving or not. It's actually rather elegant and counter intuitive. Well for me.

To relate it back to my original point, you can't simply disregard a perspective because you want to, not unlike the case with the black hole. The perspectives must be explainable or one arrives at a paradox (or an apparent one). You cannot simply will away one as irrelevant.



Clearly.

Perhaps for distant observers they never see a black hole, but for those falling in, a black hole exists.

I don't try to will away the perspective of the black hole in-faller.......the model I believe in is one where the in-faller would see the collapsing ball less and less magnified, until he was just part of a small, time dilated, eternally collapsing object.....I think this small ETO is seen, by the distant observer, spread out as the matter falling towards what looks like an event horizon, but to the in-faller it is just a small ball....I don't know how big the ball would look for such time dilation; maybe a grain of sand(for a stellar mass BH)?

 

[beancounter]

Next week, we should cover quantum entanglement.

Oh, what a tangled web we weave, when we practice to deceive.

 

[nog]

I don't try to will away the perspective of the black hole in-faller.......the model I believe in is one where the in-faller would see the collapsing ball less and less magnified, until he was just part of a small, time dilated, eternally collapsing object.....I think this small ETO is seen, by the distant observer, spread out as the matter falling towards what looks like an event horizon, but to the in-faller it is just a small ball....I don't know how big the ball would look for such time dilation; maybe a grain of sand(for a stellar mass BH)?

Okay, but I think the underlying physics and what is actually seen are two different issues. Like in Special Relativity, the underlying physics isn't necessarily what is seen. I remember some computer programs (I assume there are still some, but am not up to 'speed' on the current programs) that would show objects (that you could model in some modeling program then input into the program) traveling at relativistic speeds and how they would appear (which is a different issue from simple length contraction).

Perhaps different isn't the right word, but 'built upon'. You have to know the underlying physics so that you can then model the appearance.

As for the bolded part, the object falling in would never experience the actual time dilation, time would advance as usual according to its own clock. Assuming a black hole existed, it would cover a finite distance, pass through the event horizon noticing nothing special at that place and continue on to land on the surface (or into the singularity). In a finite amount of time this would all occur as experienced by the falling in object. Assuming it could experience and not be spaghetti-fied and ripped apart by tidal forces.

 

[Blobbenstein]

well, like I said, I think going though the event horizon is like going through the north pole and going further north.

 

[Blobbenstein]

.

As for the bolded part, the object falling in would never experience the actual time dilation, time would advance as usual according to its own clock. Assuming a black hole existed, it would cover a finite distance, pass through the event horizon noticing nothing special at that place and continue on to land on the surface (or into the singularity). In a finite amount of time this would all occur as experienced by the falling in object. Assuming it could experience and not be spaghetti-fied and ripped apart by tidal forces.

well, no one "experiences" time dilation; we all experience time as we normally do, but as someone falls towards a black hole, time would slow down for them, as seen by the distant observer.

I just think that "inside the event horizon" is a non-existent palace; an illusion created by gravitational self-magnitism. All that really exists is the infalling matter and the space it falls in.........I reject the event-horizon/singularity idea.

I do wonder, if all you have is a ball of collapsing matter, what the evaporation process is....that's the thing; it is probably a very important quantum process, a thing that happens to ultra-dense matter....while scientists are pondering the non-existent event horizon, there is that process going un-studied......I do think that BHs evaporate, but not via the Hawking Radiation process, but a process which probably matches quantitatively the HR process.

 

[Blobbenstein]

anyway, do you see that an object gravitationally self magnifies?
And what effect does that have on a collapsing ball of matter?

 

[Blobbenstein]

here's a diagram I made a while ago:

So from the outside, it looks like the infaller would gradually fall towards the outer event horizon, but that would be an illusion.....

Maybe if Steven Hawking could just walk down the pub and have a pint of beer or eight, he would see things differently....but he is kind of stuck in a hole.


eta: and maybe I shouldn't have put the distant observer at an infinite distance away...but you get the idea: a distant observer.

 

[das_nut]

Your diagram doesn't make any sense - why would the apparent position be different?

 

[das_nut]

I don't get it.

I was referring to oddities in science. Quantum entanglement happens in a way that is non-intuitive.

 

[FortyTwo]

 

[Blobbenstein]

Your diagram doesn't make any sense - why would the apparent position be different?

because we would see where the light was coming from along the trajectory it was on when it entered our eyes, even though it had a curved path.
We would see the light source along the tangent at the place where it entered our eye.

 

[Blobbenstein]

here is a PDF page on self magnification and stuff:
http://www.spacetimetravel.org/licht/light.pdf

bit beyond me, but some pretty pictures.

like:

 

[nog]

well, like I said, I think going though the event horizon is like going through the north pole and going further north.

Unfortunately, that's just not the way the math works out.

well, no one "experiences" time dilation; we all experience time as we normally do, but as someone falls towards a black hole, time would slow down for them, as seen by the distant observer.

I agree. Which is really the only reason why, to me, one can say it takes an infinite amount of time for a black hole to form, therefor, they cannot exist (as a singularity). Or at least not yet, unless time has passed for an infinite amount of time already, then I'd admit that black holes could exist.

I just think that "inside the event horizon" is a non-existent palace; an illusion created by gravitational self-magnitism. All that really exists is the infalling matter and the space it falls in.........I reject the event-horizon/singularity idea.

The self magnification you talk about is simply gravitational lensing. I'm familiar with it. The exact details would depend on the mass of the object. However, it's not clear to me that an event horizon is just due to gravitational lensing. I'd have to see the details (the math/calculations).

The event horizon is a mathematical structure that is just due to points of view. There is a similar horizon due to the expansion of the universe as well as a horizon due to an accelerating particle. It's a mathematical construct that has very real effects (aside and independent from any gravitational lensing).

So the event horizon of a black hole, with regard to the universe (as in a distant observer) can be calculated by the Schwarzschild radius (if I remember correctly). As you fall in, that event horizon is in relation to a distant observer, but one could calculate exactly when that would occur. However, as you fall in, you'd forever see an event horizon in front of you, even after you cross the black hole event horizon.

I do wonder, if all you have is a ball of collapsing matter, what the evaporation process is....that's the thing; it is probably a very important quantum process, a thing that happens to ultra-dense matter....while scientists are pondering the non-existent event horizon, there is that process going un-studied......I do think that BHs evaporate, but not via the Hawking Radiation process, but a process which probably matches quantitatively the HR process.

My understanding is that Hawking radiation is just black body radiation (details in thermodynamics). However, Hawking radiation specifically was trying to show, using QM, how this process occurs.

 

[nog]

anyway, do you see that an object gravitationally self magnifies?

Yes. However, the exact details depend on the given circumstances.

And what effect does that have on a collapsing ball of matter?

It has no effect on the collapsing matter. It does have an effect on what a person at some point sees though. However, like I already stated, this is independent to the underlying physics of what is an event horizon. The event horizon is based on the curvature of space time and the position of an observer, but is not due to the light paths taken from the collapsing matter to the observer.

 

[Blobbenstein]

Unfortunately, that's just not the way the math works out.

Well, I don't know the details of the maths.

I've read that there is no time dimension at or within the supposed event horizon.

I would like to study it more...but I think I'll have to leave it until I get some sort of brain enhancement.

But what you say about the infaller always seeing the EH bellow him, seems to go along with what I believe....The in faller sees the event horizon always bellow him, and the distant observer sees the infaller fall slower and slower towards the EH......those two perspectives seem to match without anyone crossing any event horizon.

 

[nog]

I've read that there is no time dimension at or within the supposed event horizon.

I think that's because, based on a distant observer there is none. However for an object falling in, or even an object really close to a black hole there is nothing special at the Black Hole Event Horizon (as calculated for the distant observer).

But what you say about the infaller always seeing the EH bellow him, seems to go along with what I believe....The in faller sees the event horizon always bellow him, and the distant observer sees the infaller fall slower and slower towards the EH......those two perspectives seem to match without anyone crossing any event horizon.

Just to be clear they're two different event horizons. It can be calculated when the 'infaller' would reach the EH has viewed by a distant observer. They actually cross this distance noticing nothing special, however they do notice an ever changing (in terms of distance) EH below them.

This assumes a black hole already exists.