# Time Dilation and Black Hole Inflation

1. Feb 24, 2006

### InfernoSun

Here's the idea:

As one approaches the event horizon of a black hole, gravity increases, and time slows. The outside universe appears to speed up. The rate of infalling matter increases, which is consumed by the black hole to increase it's mass. The Schwarzschild radius of the black hole varies with mass, so the black hole grows in size faster and faster. When one crosses the event horizon, the rate of infalling matter approaches infinite and the black hole sucks in the whole outside universe, and inflates to the corresponding size, which is larger than the visible universe. So the end-effect is that a black hole is a secondary explosion triggered by a supernova (like how a fission bomb triggers a fusion bomb), but which has the critical density for a chain reaction that consumes the entire universe. A space-time explosion.

Opinions?

Last edited: Feb 24, 2006
2. Feb 24, 2006

### pervect

Staff Emeritus
This isn't what happens at all.

There are several concepts of mass in physics, the most useful concept is "invariant mass", which is the only sort of mass that's a property of the object itself.

The invariant mass of a black hole does not change with velocity.

The Schwarzschild radius of a black hole does not change with velocity either.

The above are mostly defintional points, let's look at some phsics. It is true to some extent that gravity is affected by velocity, but the relationship is more complex than you think it is.

It is instructive to look at the tidal forces on an observer falling into a black hole, and how they depend on velocity. For a stationary observer, the tidal force in GR is the same as that of the tidal force in Newtonian physics - it is proportional to the mass of the black hole and inversley proportional to the radius (in the case of the black hole, that's the Schwarzschild R coordinate).

F = GM/r^3

An observer falling into a black hole can't measure the acceleration of gravity directly (he is in free fall, that's really all he can measure), but he can measure how fast gravity changes, he can measure the tidal force.

If we have two observers at the same point in space-time, one falling into a black hole, and one stationary (at a constant Schwarzschild radius) they will experience exactly the same tidal forces.

Interestingly enough, however, if you look at someone moving not into the black hole, but at right angles to it, the tidal force on such a transversly moving observer WILL increase due to his velocity.

So that's the simplest description of the end result - the tidal forces do not change for the infalling observer, but they do change for an obsever who is moving in other directions.

A crude way of looking at it that's not entirely accurate but helpful is to imagine the "gravitational field" of a black hole as being a little bit like the electric field of a moving charge. The field is not uniform, but it gets "squished" by the Lorentz contraction.

See for instance http://www.phys.ufl.edu/~rfield/PHY2061/images/relativity_14.pdf

and rember that this is just a crude approximation.

Probably the most important thing that your analysis is missing is the concept of genreal covariance.

This means that analyzing the problem in the frame of reference in which the sun is stationary, and the obsever moves rapidly must give the same answer as analyzing the problem in which the observer is stationary, and the sun moves rapidly.

Your approach does not have this important property, because you get different answers depending on which frame of reference is used.

Physics in general and GR specifically does have this property - the frame of reference does not matter to the answer.

Last edited by a moderator: Apr 22, 2017
3. Feb 26, 2006

### InfernoSun

1. Is it true that an atomic clock will run faster at a higher altitude where gravity is weaker?

2. Would time slow down almost to a stop as one approaches infinitesimally close to a black hole event horizon?

3. If time slows down near a black hole, then from a vantage point very near a black hole event horizon wouldn't the rate of infalling matter increase, since the universe further away is not affected by time dilation?

4. At the event horizon, wouldn't all the matter in the whole universe get sucked into the black hole, and the size of the black hole expand to fill the universe, maybe become a new universe?

5. Wouldn't all the matter getting pulled into the event horizon be length contracted, and therefore accumulate into a thin massive shell as the whole shebang gained mass and the event horizon moved outwards?

6. Don't massive shells exert zero net gravitational force on objects inside them?

7. At the instant the event horizon is crossed, assuming one survived, wouldn't one then find oneself inside a large empty space?

8. Wouldn't Hawking radiation be emitted into this empty space?

9. Wouldn't radiation emitted by the event horizon be highly redshifted, since the event horizon increased in radius at such a huge rate?

10. Isn't a black hole a black body emitter?

11. Could this Hawking radiation be shifted into the microwave spectrum, if viewed from the inside?

12. Could we be inside a black hole now?

13. Could the cosmic microwave background be redshifted Hawking radiation, essentially an image of the inside of the event horizon?

14. Black holes begin as supernovae, with only 6-15 solar masses. Could Hawking radiation from accreted matter outside the black hole, have led to baryogenesis inside the black hole?

15. Could these questions form a more complete cosmological model?

16. Should I be nominated for a nobel prize? :-)

4. Feb 27, 2006

### pervect

Staff Emeritus
Yes, though gravitational time dilation is a function of gravitational potential energy, not gravitational acceleration. Deep inside the Earth, for instance, there is no gravity, but there is still gravitational time dilation.

Yes - IF one hovers there, via constant acceleration.

See above. You might also find the sci.physics faq entry useful

http://math.ucr.edu/home/baez/physics/Relativity/BlackHoles/fall_in.html" [Broken]

Nope, nothing particularly special happens at the event horizion when you fall into a black hole (you fall in without trying to hold station).

Aside from the sci.physics.faq on the topic, Ted Bunn has a FAQ, which includes some questions about falling in

http://cosmology.berkeley.edu/Education/BHfaq.html

Hopefuly that's enough answers for now, anyway I have to go.

Last edited by a moderator: May 2, 2017
5. Feb 28, 2006

### InfernoSun

I've read Einstein's book, "Relativity: The Special and the General Theories" and he specifically used centripetal force at a point on the rim of a spinning disk as equivalent to gravitational force. The tangential velocity gives time dilation and length contraction values, in accordance with the special theory, for any equivalent force including gravity. This is the basis for general relativity.

So, time runs slower in a gravity well. A stationary observer near a black hole event horizon will see the universe further away speed up. All the matter and energy that was every going to fall into the black hole will very quickly succumb to that fate. If all the matter in the universe was doomed to that fate, it might happen in a matter of seconds from the perspective of the hovering observer. Nothing in your website links suggested this idea was in error. In fact they seemed to gloss over it. Maybe the authors weren't sure.

So you got stuck on question #4. I suppose I neglected to fill in a causal relationship, and state my assumptions, before posing that question. The statement of fact is that the Schwarzschild radius of a black hole with a mass equal to the estimated mass of the observable universe is larger than the observable universe. It is therefore possible that we live inside a black hole. My assumption was that we do live inside a very big black hole, and as such no matter or energy can escape. I also assume that smaller black holes exist, such as at the centers of galaxies, mostly formed from supernova explosions. The big picture then is of small black holes (supernova remnants) within a very large black hole (our universe). Any loose bits of matter and energy that are sailing between the stars cannot escape the universe and will follow paths that eventually collide with a smaller black hole. Therefore, all matter and energy in the universe will fall into a black hole. An observer hovering near the event horizon of one of these smaller black holes will see this come to pass at an accelerated rate. All the mass of the observable universe would be added to the smaller black hole, and it would then inflate to the corresponding Schwarzschild radius, and mimic its parent universe. Hence the following questions:

4. Wouldn't all the matter in the whole universe get sucked into the black hole, and the size of the black hole expand to fill the universe, maybe become a new universe?

5. Wouldn't all the matter getting pulled into the event horizon be length contracted, and therefore accumulate into a thin massive shell as the whole shebang gained mass and the event horizon moved outwards?

6. Don't massive shells exert zero net gravitational force on objects inside them?

7. At the instant the event horizon is crossed, assuming one survived, wouldn't one then find oneself inside a large empty space?

8. Wouldn't Hawking radiation be emitted into this empty space?

9. Wouldn't radiation emitted by the event horizon be highly redshifted, since the event horizon increased in radius at such a huge rate?

10. Isn't a black hole a black body emitter?

11. Could this Hawking radiation be shifted into the microwave spectrum, if viewed from the inside?

12. Could we be inside a black hole now?

13. Could the cosmic microwave background be redshifted Hawking radiation, essentially an image of the inside of the event horizon?

14. Black holes begin as supernovae, with only 6-15 solar masses. Could Hawking radiation from accreted matter outside the black hole, have led to baryogenesis inside the black hole?

15. Could these questions form a more complete cosmological model?

16. Should I be nominated for a nobel prize? :-)

6. Mar 1, 2006

### pervect

Staff Emeritus
Yes, for a stationary obsever hovering above a black hole, the outside universe will appear to age faster. That much I can agree with. If it were possible to hold station close enough to a large enough black hole, one could watch the universe age very rapidly.

Note that a non-stationary obsever (one falling into the black hole) sees things rather differently, as per the faq.

What was question 4 again? Oh yeah, here we go:

This seems more like outrageous speculation than a question to me.

There is no particular reason to believe that all the matter in the universe is going to get sucked into one particular black hole.

In fact, the most recent results show that gravity is not even slowing down the expansion of the universe - rather than deaccelerating, the expansion of the universe appears to be accelerating.

Therfore objects far enough away from the black hole are unlikely to wind up in it, because distant objects are not only not getting closer to the black hole, they are moving away from it, and the velocity at which they are moving away is increasing rather than decreasing.

You sure did. You also seem to be engaging in quite a bit of rather wild speculation thinly disguised as a question as well.

It is highly unlikely that wew are living inside a black hole. See for instance

http://math.ucr.edu/home/baez/physics/Relativity/BlackHoles/universe.html" [Broken]

The universe has a singularity in its past (the Big Bang). This is not a good fit to the black hole, which would suggest that the singularity should lie in the future. The accelerating expansion of the universe is also not a good fit to a black hole - current estimates put the average density of matter at .1 of that needed for recollapse (IIRC), even without dark energy. With "dark energy" playing such a large role, re-collapse is currently not even on the table for serious cosmological models.

See above.

Last edited by a moderator: May 2, 2017
7. Mar 1, 2006

### InfernoSun

From the link that you posted:

"The previous argument against the big bang being a black hole still applies. The black hole singularity always lies in the future light cone whereas astronomical observation clearly indicate a hot big bang in the past."

The astronomical evidence that they give is the Cosmic Microwave Background. I've suggested that the CMB is actually redshifted Hawking Radiation being emitted from the event horizon to the interior of the black hole. I've also hypothesized that if the universe is a black hole then nothing can escape, and will bounce around until colliding with a smaller black hole. Ergo, the singularity IS in the future.

The established theories that you have cited seem to assume a single black hole, or a single white hole, or a single "element" comprising the entire cosmos. I have instead assumed multiple, nested black holes. A black hole appears to be a singularity from the outside, and a flat spacetime on the inside, due to a temporal rate transition and Schwarzschild inflation at the event horizon. What an astronomer sees through the telescope is the CMB billions of lightyears away, representing the outer boundary. At the centers of galaxies the astronomer sees singularities, representing the inner boundary, or "transition" horizon, or "portal" to the next universe. Whatever terminology you prefer. I think it's rather consistent. It seems to stand up rather well to criticisms.

As for wild speculation, I'm also being consistent with prior theories, such as dark energy, and white holes, and the implicate order and all that jazz. Don't you think that a lightspeed delay and relativistic effects are more likely explanation for the expansion of the universe than "dark energy"? The apparent size of the universe slowly catching up to the geometric size seems more believable to me. Just as the apparent position of the planets lags behind their geometric positions (just a little tidbit I learned from astronomy). The image of Mars for example accelerates in a circle as it tries to catch up to the geometric position of the planet. This may be a direct analogy. Although I can only imagine a perfect spherical shell as the outer boundary of the universe, the apparent shape of the cosmos may be following a more complex path as it catches up to the geometric shape. That geometric shape may be static or it may be dynamic. Hard to say. Maybe it is dynamic! Well, my imagination has its limits.

Last edited: Mar 1, 2006
8. Mar 3, 2006

### pervect

Staff Emeritus
Are these theories of yours above published in any peer-reviewed journals? If they are, now is your chance to give some references.

(I tend to doubt it, my impression is that they are your own personal ideas that you've become very attached to, in spite of the fact that they are a long, long ways away from anything approaching the mainstream).

9. Mar 4, 2006

### InfernoSun

Thanks for that intelligent feedback, thanks so much. To be as blunt as yourself, published theories are unintelligible tripe. It must be embarrassing for 'real' scientists to know that I can come up with ideas all by myself that attempt to explain all the phenomena that their theories attempt to explain, and then go further to explain some that their do not. My ideas even hypothesize an answer to the question "What came before the Big Bang?" But I'm sorry, you obviously see this as some sort of blasphemy against doctrine. I apologize. My condolences.

10. Mar 4, 2006

### pervect

Staff Emeritus
You should re-examine the forum guidlines that you signed to get a better idea of what we discuss on this board, why, and where.

Unpublished personal theories are not generally welcomed in the main forums. There is an independent research forum for presentation discussion of non-mainstream theories, but it has fairly strict guidelines of its own.

Statements like "published theories are unintelligible trip" are generally not welcome anywhere on the board,. If that's your attiutde, you probably won't last very long here.

11. Mar 4, 2006

### Janus

Staff Emeritus
InfernoSun,

If you wish, you can submit your ideas to our Independant Research forum. In the meantime, I am locking this thread.