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[bjlong]

What happens to light traveling straight into a black hole?

It gets blue-shifted. That is, its wavelength changes to show an increase in energy. Somewhat counter-intuitive, but think of it like a ball rolling down a hill--it's going to pick up energy. But since light can't speed up, it instead changes to a wavelength with a higher energy.

It's a pretty important aspect of modern astronomy, too, so good job picking up on this question.

[G-Flex]

Well, I'm happy to keep providing an alternative viewpoint if you ever get tired (or upset) with your current one. It's not like I'm pressing my beliefs onto someone.

The problem is that coming up with "alternative viewpoints" is pretty useless when they involve a field you pretty much have no clue about. You might as well be pulling ideas out of a hat.

And to the rest of the people accusing me of dropping to sci-fi jargon - pardon me, you're accusing me of not believing in stuff I don't yet know to be true.

No, I didn't. Being skeptical is great.

However, there's a difference between being skeptical and what you're doing.
Being skeptical is when you're unsure of the truth given a lack of evidence or understanding.
What you're doing is coming up with your own truth due to a lack of understanding on your part. You don't understand the science or even the terminology involved, and this is a really damn tough science, yet you still somehow have enough confidence in yourself to think that your own "alternative viewpoints" can hold water.


A lot of science seems wrong or counterintuitive before you understand it well enough, and that should go double for things as unintuitive as relativity, astrophysics, etc. A scientific person will easily find things that seem wrong about a scientific law or theory when he first hears about it, or will come up with situations where it's said to apply but seems not to. Hell, this even applies to relatively simple things like fluid pressure laws. It also happens a lot with the laws of thermodynamics; sometimes you might think of something that seems to be an infinite source of energy (or perpetual motion machine), but the solution is to look into the theory and see if there's a reason why you're wrong, not to assume that you've found some amazing alternative.

[Neruz]

The problem is that coming up with "alternative viewpoints" is pretty useless when they involve a field you pretty much have no clue about. You might as well be pulling ideas out of a hat.

For my next trick; a Rabbit!

[eerr]

The problem is that coming up with "alternative viewpoints" is pretty useless when they involve a field you pretty much have no clue about. You might as well be pulling ideas out of a hat.

For my next trick; a Rabbit!

Ditch that subtitle dude.

[JoshuaFH]

I was hoping Jack would jump in.

[Virex]

What happens to light traveling straight into a black hole?

It gets blue-shifted. That is, its wavelength changes to show an increase in energy. Somewhat counter-intuitive, but think of it like a ball rolling down a hill--it's going to pick up energy. But since light can't speed up, it instead changes to a wavelength with a higher energy.

It's a pretty important aspect of modern astronomy, too, so good job picking up on this question.

Besides that, since a black hole is a singularity, there is no such thing as directly into the singularity (it's infinitismally small), so any light shot "almost" directly at the singularty, and then it'll turn around and go back to the other edge of the event horizon (the acceleration working on the photons at this moment will be quite absurd, because they're making a 180 degrees turn while maintaining a speed of C, all while going along an eliptical trajectory with a short axis of far less then a picometer). This means that if you'd be inside the event horizon of a black hole, you'd constantly see light comming from all directions, since even a minute deviation in the way light enters the event horizon causes a completely diferent trajectory. For example, any light comming in at a 90 degrees angle with the event horizon and hitting the event horizon will make a perfect circular orbit at the event horizon, the sphere of light.

This realtes to something else I thought of. Generaly, a singularty is assumed to actualy exist. But wouldn't the space-time curving effects of gravity prevent matter from actualy reaching the singularity itself? After all, the closer matter (and energy) comes to the singularity, the more time dialatation it's going to experience, and if the gravity goes to infinity, so does the dilatation. It's been said that Hawking radiation would cause a black hole to evaporate long before you reached the singularity, but why is this not true for the matter that is to form a new black hole?
One would expect the singularity to be virtual, that is there appears to be a singularity, but only from the outside, since in the inside matter hasn't reached the centre yet and never will.

[bjlong]

This realtes to something else I thought of. Generaly, a singularty is assumed to actualy exist. But wouldn't the space-time curving effects of gravity prevent matter from actualy reaching the singularity itself? After all, the closer matter (and energy) comes to the singularity, the more time dialatation it's going to experience, and if the gravity goes to infinity, so does the dilatation. It's been said that Hawking radiation would cause a black hole to evaporate long before you reached the singularity, but why is this not true for the matter that is to form a new black hole?
One would expect the singularity to be virtual, that is there appears to be a singularity, but only from the outside, since in the inside matter hasn't reached the centre yet and never will.

Well, some of your questions are speculating about the inside of the singularity. All I can say is have fun.

However! You bring up Hawking Radiation, which has not been experimentally observed as of yet, IIRC. And there are some theorists who claim that it's unlikely to be true. etc, etc, etc.

The black hole question is a good one, though, and you might want to contact an astrophysicist for the answer.

[Muz]

I get the feeling up to half the answers on this thread are incorrect. But I'm not even going to bother to check.

[Starver]

Besides that, since a black hole is a singularity, there is no such thing as directly into the singularity (it's infinitismally small), so any light shot "almost" directly at the singularty, and then it'll turn around and go back to the other edge of the event horizon [...]

Except that the inexorability of light falling 'towards' the singularity (see below for an agreement, as opposed to an objection) means that it's not a matter of light 'sloshing around' within the Event Horizon.  More like... (well, I suppose intentionally like..., seing as it's supposed to be a model of same) those "gravity wells" that you can send balls into where they can loop around.  Down to a certain point, you can engineer an eliptic (give or take loss of energy through air and material resistance) coming back up to the level of release, but after a certain depth you can only really see them going downwards (although, due to intrinsic classical effects its a fast orbital barely downwards rather than dragged mostly 'down').

Or perhaps, to remove the classical effects altogether, don't use the ball and instead painstakingly draw a line on the surface.  A straight line (across the constraints of the warped surface).  Some lines will merely go 'around' the hole, but some lines you draw will lead down into the funnel and never emerge.  The distinct diameter of hole which no line can pass without ending up 'only going downwards' from then on is the event horizon.  (Even then, there are flaws in the analogy, but different flaws.)

This realtes to something else I thought of. Generaly, a singularty is assumed to actualy exist. But wouldn't the space-time curving effects of gravity prevent matter from actualy reaching the singularity itself?

Now, this is more or less relevent to a prior reply of mine to someone regarding infinities.  In a perfect 'model' gravity well (the 'toy' ones are obviously finite in depth, and are probably designed to asymtotically close to 'just larger than the ball-size' anyway), the slope gets steeper and steeper (close to, but not vertical) and the slice across at that level reveals a smaller and smaller hole (close to, but not, of zero size) but it's an infinitely deep slope which never quite closes.  Thus there is no part of the model that relates to the point of the singularity.

However...

After all, the closer matter (and energy) comes to the singularity, the more time dialatation it's going to experience[...]

Beyond the event horizon, time dilation isn't really applicable any more, in the same manner.  A simple (wrong, but indicative) explanation is that v>c, so root(1-(v^2/c^2)) in the various equations is root(1-(>1)) is root(<0) and thus an imaginary number.  Which (given time works like an 'imaginary' dimension in various other formulae encompassing space and time coordinates) lends support to the whole "time becomes space, space becomes time" idea.

It's been said that Hawking radiation would cause a black hole to evaporate long before you reached the singularity, but why is this not true for the matter that is to form a new black hole?

I suspect because it's not a matter of the mass needing to be "at" the future singularity point to create the black hole, but that sufficient mass finds itself within either the event horizon or Schwarzchild radius.  (Actually, isn't that the definition of the SR?  I forget.  Must check Wiki or something at some point. , there then forms a 'singularity-centred' funnel (where previously there was just a dimple of whatever depth).  And (through quantum uncertainty) no actual matter or energy (e.g. baryon, electron, quark, photon, gluon, Higgs boson, graviton, whatever) will be precisely 'at' the virtual point in space that is the 'singularity-centre' to cause complications, and now you just have to worry about whether the energy and matter that form (or later fall into) the black hole loses its identity or not in the warping of space-time.

One would expect the singularity to be virtual, that is there appears to be a singularity, but only from the outside, since in the inside matter hasn't reached the centre yet and never will.

For an external observer, that's definitely the case.  You never even see anything pass the event horizon and (assuming an unobstructed view, the ability to handle the doppler issues and of course patience) would see it on the verge of disappearing 'forever' (or until the hole evaporates, when... ).  Holding a hypothetical external-to-the-universe POV (which is severaly flawed due to assumptions we must make and the manner of our descriptive language) it would be seen to be either forever 'falling' down the gravity well, beyond the EH level.  Perhaps doing so in a form without the original identity and physical limitations (thus allowing the evaporation).  But when the well loses efficacy and snaps back into a mere 'dimple', the mass and energy that remains exists smeared out everywhere except the precise (virtual) point of the singularity.

Of course, there's an issue about the potential discontinuity in the space-time as it converts between dimple and funnel, and vice-versa, but that's a question of cosmological topology that I shall leave unexplained, for want of the descriptive language I want.


Actually, all the above is really poorly described, for which I must apologise.

[DreamThorn]

@Muz:  I'd say at least half of the answers are at least half-way wrong, rather than at most.

[Neruz]

Jesus fucking christ we're onto the physics of what happens inside a Black Hole?

Step away people. Step far away. You are entering the realm of dark. evil magic that terrifies String Theorists.

[dreiche2]

Beyond the event horizon, time dilation isn't really applicable any more, in the same manner.  A simple (wrong, but indicative) explanation is that v>c, so root(1-(v^2/c^2)) in the various equations is root(1-(>1)) is root(<0) and thus an imaginary number.  Which (given time works like an 'imaginary' dimension in various other formulae encompassing space and time coordinates) lends support to the whole "time becomes space, space becomes time" idea.

[citation needed]

[Neruz]

You won't find one dreiche; anything making sense inside a Black Hole is, as of modern science, a complete fantasy.

I actually have one physics professor on record as stating that inside a Black Hole "Shit gets wierd."

[Muz]

@Muz:  I'd say at least half of the answers are at least half-way wrong, rather than at most.

Halfway wrong is still wrong. I actually looked over some posts. Yeah, it's like 30% correct, 40% empty babble, 10% false, and 20% stuff-i-dont-understand (likely babble or false). Unfortunately, the false stuff just ruins the whole conclusion. Anyone who's here to learn stuff should stay away.

Heh, I have this thing against people saying wrong things (that can't be proven wrong easily) just to sound smart. A lot of people making mistakes with basic assumptions, but damn, correcting it is like correcting someone in a religious thread.

[eerr]

@Muz:  I'd say at least half of the answers are at least half-way wrong, rather than at most.

Halfway wrong is still wrong. I actually looked over some posts. Yeah, it's like 30% correct, 40% empty babble, 10% false, and 20% stuff-i-dont-understand (likely babble or false). Unfortunately, the false stuff just ruins the whole conclusion. Anyone who's here to learn stuff should stay away.

Heh, I have this thing against people saying wrong things (that can't be proven wrong easily) just to sound smart. A lot of people making mistakes with basic assumptions, but damn, correcting it is like correcting someone in a religious thread.

give proper introduction for quantum mechanics.