Mike Holland

2011-May-12, 01:38 AM

I am posting this under ATM, but it is pure Mainstream. I am not proposing any new theory, just pointing out aspects of existing theory which many people are unaware of.

When discussing black holes, there are basically two points of view, that of a remote observer and that of a poor spaceman who falls into one. The difference is caused by gravitational time dilation. From the remote viewer’s point of view (or in his time frame, if you prefer), the passage of time is retarded near the black hole, and comes to a complete stop at the Schwarzschild radius. So as far as he is concerned, the falling spaceman never reaches the Schwarzschild radius (which for convenience I will abbreviate to R0), but hovers just outside it gradually edging closer and closer. The spaceman, in turn, would have a very different experience, falling through R0 in a very short period of time.

The consequence of this is that as far as the outside universe is concerned, the spaceman never enters the black hole. And neither does any other falling matter. Nothing has ever fallen into a black hole as far as our clocks are concerned!

But you don’t need a black hole to get time dilation. We have it right here due to Earth’s gravitational field, as has been measured using atomic clocks in orbit. We ourselves are time-delayed relative to a remote observer in space. So a super-massive collapsing object which is nearly a black hole would itself be highly time dilated (by our clocks), and the collapse process itself would slow down and come to a complete stop just as it reaches black hole status - when our clocks read infinity.

What we end up with is an object collapsing more and more slowly as it tries to fit within its Schwarzschild radius, and this almost EH area becomes extended as more material falls onto it. The almost-EH is not a surface, but a whole volume of the collapsing mass, with never enough mass within that radius to actually form an event horizon.

Here are some big guns to back up this picture of events:

“What would happen if you fall in? As seen from the outside, you would take an infinite amount of time to fall in, because all your clocks – mechanical and biological – would be perceived as having stopped’”

- Carl Sagan “Cosmos”, 1981

“ .. a critical radius, now called the “Schwarzschild radius,” at which time is infinitely dilated.”

- Paul Davies “About Time”, 1995

“From the standpoint of an outside observer, time grinds to a halt at the event horizon.”

- Timothy Ferris “The Whole Shebang”, 1997

“The closer we are to the event horizon, the slower time ticks away for the external observer. The tempo dies down completely on the boundary of the black hole.”

- Igor Novikov “The River of Time”, 1998

“When all thermonuclear sources of energy are exhausted a sufficiently heavy star will collapse. This contraction will continue indefinitely till the radius of the star approaches asymptotically its gravitational radius.”

- Oppenheimer and Snyder “Phys.Rev. 56,455” 1939

“According to the clocks of a distant observer the radius of the contracting body only approaches the gravitational radius as t -> infinity.”

- Landau and Lifschitz “The Classical Theory of Fields”, 1971

“What looks like a black hole is “in reality” a star frozen in the very late stages of collapse.”

- Paul Davies “About Time”, 1995

“At the stage of becoming a black hole, time dilatation reaches infinity.”

- Jayant Narlikar

In all his writings, Fred Hoyle referred to them as “near black holes”.

The problem, as I see it, is that everyone has become obsessed with the time frame of a falling observer, because it is mathematically so much more interesting. Frozen stars are very dull. And so many people do not realize that all the black hole phenomena do not occur in the universe we live in, but only beyond the far end of time when the universe is infinitely old.

At this point I would like to mention different time dilation processes which occur. For a static object, suspended near R0 (not possible, I know!), we would only observe the gravitational time dilation. For a falling object we have, added to this, the Doppler effect due to the speed of the object away from us, and another apparent dilation due to the longer and longer time it takes for light signals to escape the gravity as the object moves in. This last light signal delay is often confused with the delay effect of gravity itself.

Now, just out is interest, I will add some figures to the time dilation process.

Einstein’s General Relativity states that relative to a remote viewer, time is dilated in a gravitational field, and in the Schwarzschild metric the dilation in the vicinity of a non-rotating massive spherically-symmetric object is governed by the formula

dT/dt = √(1 - r0/r)

where dT = proper time interval of the falling object

dt= time interval observed by remote viewer

r = distance from the centre of the black hole

r0 = Schwarzschild radius of the black hole.

To simplify calculations, I will replace r with r0+dr, so that dr is the distance from the Schwarzschild event horizon.

Then (1 – r0/r) = ((r0 + dr)/(r0+dr) – r0/(r0+dr)) = (dr/(r0+dr)) = dr/r0 for dr<<r0.

And so, close in to the Schwarzschild radius,

dT/dt= √(dr/r0)

Next I will consider a black hole with mass about 3x the mass of the sun, and radius 10 km.

Then at a distance of 1 meter, we have dT/dt = √ 1/10,000 = 1/100, so one minute of local time at the falling object would correspond to 100 minutes in our time frame. Using this method, we can easily find the distance from the event horizon for any degree of time dilation we choose. For a dilation of 1:10^6 we need dr/r0 = 10^-12.

Obviously we need to get very close to the EH to achieve a respectable amount of dilation. At the surface of a neutron star it is only 20%! How close can we go? Well, the smallest distance we can consider is the Planck length, 1.6x10^-35m. Then

Dr/r0 = 1.6x10^-39, and dT/dt= 4x10^-19. A year is just over 3x10^10 seconds, and so a one second interval at this distance would pass in about 100,000,000 years in our timeframe. If two objects fell passed this point on two successive days in local time, then in our time frame we would see them pass this point about 10,000,000,000,000,000 years apart (IF we could see anything this close in).

But because the time dilation effects occur so close in to the EH, it would be impossible to detect them. So no observation would show the difference between a black hole and an eternally collapsing object.

To avoid repetition, here are some objections posted by WayneFrancis in another topic:

“If stuff really didn’t ever cross the EH of a black hole then they’d be far from black. They’d just have very long radio wavelengths. This is where it gets into what really happens. Because take the 3600x time dilatation. If I had a green shirt on then that green shirt would no longer be green to an external observer.

I’ll go through the maths.

Green wavelength – 545 nanometers or 5.45x10-7

At a time dilatation of 3600x its wavelength would now be 1.962x10-3m

This is on the border between infrared and microwave radiation. VERY easily picked up.

Now work out how close an object would have to be to be time dilated to something like 10Hz. I’ll give you a clue … you’d have to have something time dilated by

~1.000.000.000.000.000 times.

So if things didn’t actually fall through the EH then in theory we would still be receiving photons from them that we could pick up for like 10 million years or so.

The objects DO pass the event horizon and the proof is not only in the maths but in our observations and even if they didn’t pass through the EH, as I and others have pointed out, the EH would bubble out past that shell anyway. End effect is the same. The stuff is lost inside the EH and the only way its getting back out is the slow process of HR.”

Yes, Wayne, the maths show that objects DO pass the event horizon, but the maths also shows that it happens when our clocks read infinity. As for observations? Do you have a photograph of an object falling through? I think I have shown that our observations would not show the difference.

I have explained what happens regarding “the EH would bubble out”. There IS no EH, only a volume extremely close to being one.

I have just been re-reading Kip Thorne’s book “Black Holes and Time Warps”, an excellent description of the development of the subject. On page 218 he refers to Oppenheimer and Snyder’s view that the implosion freezes forever as measured in the static external frame but continues rapidly on past the freezing point as measured in the frame of the star’s surface. In the early 1960’s Wheeler was converted to this view. But then Astronomers became obsessed with the falling mass, and the “space” inside the event horizon, and stopped looking at the outside picture. Thorne writes “because of the enormous difficulty light has escaping gravity’s grip, as seen from afar the implosion seems to take forever; the star’s surface seems never quite to reach the critical circumference, and the horizon never forms.” But the horizon never forms because of the gravitatiional effect on time. The light delay is an optical effect, not a real time delay.

When discussing black holes, there are basically two points of view, that of a remote observer and that of a poor spaceman who falls into one. The difference is caused by gravitational time dilation. From the remote viewer’s point of view (or in his time frame, if you prefer), the passage of time is retarded near the black hole, and comes to a complete stop at the Schwarzschild radius. So as far as he is concerned, the falling spaceman never reaches the Schwarzschild radius (which for convenience I will abbreviate to R0), but hovers just outside it gradually edging closer and closer. The spaceman, in turn, would have a very different experience, falling through R0 in a very short period of time.

The consequence of this is that as far as the outside universe is concerned, the spaceman never enters the black hole. And neither does any other falling matter. Nothing has ever fallen into a black hole as far as our clocks are concerned!

But you don’t need a black hole to get time dilation. We have it right here due to Earth’s gravitational field, as has been measured using atomic clocks in orbit. We ourselves are time-delayed relative to a remote observer in space. So a super-massive collapsing object which is nearly a black hole would itself be highly time dilated (by our clocks), and the collapse process itself would slow down and come to a complete stop just as it reaches black hole status - when our clocks read infinity.

What we end up with is an object collapsing more and more slowly as it tries to fit within its Schwarzschild radius, and this almost EH area becomes extended as more material falls onto it. The almost-EH is not a surface, but a whole volume of the collapsing mass, with never enough mass within that radius to actually form an event horizon.

Here are some big guns to back up this picture of events:

“What would happen if you fall in? As seen from the outside, you would take an infinite amount of time to fall in, because all your clocks – mechanical and biological – would be perceived as having stopped’”

- Carl Sagan “Cosmos”, 1981

“ .. a critical radius, now called the “Schwarzschild radius,” at which time is infinitely dilated.”

- Paul Davies “About Time”, 1995

“From the standpoint of an outside observer, time grinds to a halt at the event horizon.”

- Timothy Ferris “The Whole Shebang”, 1997

“The closer we are to the event horizon, the slower time ticks away for the external observer. The tempo dies down completely on the boundary of the black hole.”

- Igor Novikov “The River of Time”, 1998

“When all thermonuclear sources of energy are exhausted a sufficiently heavy star will collapse. This contraction will continue indefinitely till the radius of the star approaches asymptotically its gravitational radius.”

- Oppenheimer and Snyder “Phys.Rev. 56,455” 1939

“According to the clocks of a distant observer the radius of the contracting body only approaches the gravitational radius as t -> infinity.”

- Landau and Lifschitz “The Classical Theory of Fields”, 1971

“What looks like a black hole is “in reality” a star frozen in the very late stages of collapse.”

- Paul Davies “About Time”, 1995

“At the stage of becoming a black hole, time dilatation reaches infinity.”

- Jayant Narlikar

In all his writings, Fred Hoyle referred to them as “near black holes”.

The problem, as I see it, is that everyone has become obsessed with the time frame of a falling observer, because it is mathematically so much more interesting. Frozen stars are very dull. And so many people do not realize that all the black hole phenomena do not occur in the universe we live in, but only beyond the far end of time when the universe is infinitely old.

At this point I would like to mention different time dilation processes which occur. For a static object, suspended near R0 (not possible, I know!), we would only observe the gravitational time dilation. For a falling object we have, added to this, the Doppler effect due to the speed of the object away from us, and another apparent dilation due to the longer and longer time it takes for light signals to escape the gravity as the object moves in. This last light signal delay is often confused with the delay effect of gravity itself.

Now, just out is interest, I will add some figures to the time dilation process.

Einstein’s General Relativity states that relative to a remote viewer, time is dilated in a gravitational field, and in the Schwarzschild metric the dilation in the vicinity of a non-rotating massive spherically-symmetric object is governed by the formula

dT/dt = √(1 - r0/r)

where dT = proper time interval of the falling object

dt= time interval observed by remote viewer

r = distance from the centre of the black hole

r0 = Schwarzschild radius of the black hole.

To simplify calculations, I will replace r with r0+dr, so that dr is the distance from the Schwarzschild event horizon.

Then (1 – r0/r) = ((r0 + dr)/(r0+dr) – r0/(r0+dr)) = (dr/(r0+dr)) = dr/r0 for dr<<r0.

And so, close in to the Schwarzschild radius,

dT/dt= √(dr/r0)

Next I will consider a black hole with mass about 3x the mass of the sun, and radius 10 km.

Then at a distance of 1 meter, we have dT/dt = √ 1/10,000 = 1/100, so one minute of local time at the falling object would correspond to 100 minutes in our time frame. Using this method, we can easily find the distance from the event horizon for any degree of time dilation we choose. For a dilation of 1:10^6 we need dr/r0 = 10^-12.

Obviously we need to get very close to the EH to achieve a respectable amount of dilation. At the surface of a neutron star it is only 20%! How close can we go? Well, the smallest distance we can consider is the Planck length, 1.6x10^-35m. Then

Dr/r0 = 1.6x10^-39, and dT/dt= 4x10^-19. A year is just over 3x10^10 seconds, and so a one second interval at this distance would pass in about 100,000,000 years in our timeframe. If two objects fell passed this point on two successive days in local time, then in our time frame we would see them pass this point about 10,000,000,000,000,000 years apart (IF we could see anything this close in).

But because the time dilation effects occur so close in to the EH, it would be impossible to detect them. So no observation would show the difference between a black hole and an eternally collapsing object.

To avoid repetition, here are some objections posted by WayneFrancis in another topic:

“If stuff really didn’t ever cross the EH of a black hole then they’d be far from black. They’d just have very long radio wavelengths. This is where it gets into what really happens. Because take the 3600x time dilatation. If I had a green shirt on then that green shirt would no longer be green to an external observer.

I’ll go through the maths.

Green wavelength – 545 nanometers or 5.45x10-7

At a time dilatation of 3600x its wavelength would now be 1.962x10-3m

This is on the border between infrared and microwave radiation. VERY easily picked up.

Now work out how close an object would have to be to be time dilated to something like 10Hz. I’ll give you a clue … you’d have to have something time dilated by

~1.000.000.000.000.000 times.

So if things didn’t actually fall through the EH then in theory we would still be receiving photons from them that we could pick up for like 10 million years or so.

The objects DO pass the event horizon and the proof is not only in the maths but in our observations and even if they didn’t pass through the EH, as I and others have pointed out, the EH would bubble out past that shell anyway. End effect is the same. The stuff is lost inside the EH and the only way its getting back out is the slow process of HR.”

Yes, Wayne, the maths show that objects DO pass the event horizon, but the maths also shows that it happens when our clocks read infinity. As for observations? Do you have a photograph of an object falling through? I think I have shown that our observations would not show the difference.

I have explained what happens regarding “the EH would bubble out”. There IS no EH, only a volume extremely close to being one.

I have just been re-reading Kip Thorne’s book “Black Holes and Time Warps”, an excellent description of the development of the subject. On page 218 he refers to Oppenheimer and Snyder’s view that the implosion freezes forever as measured in the static external frame but continues rapidly on past the freezing point as measured in the frame of the star’s surface. In the early 1960’s Wheeler was converted to this view. But then Astronomers became obsessed with the falling mass, and the “space” inside the event horizon, and stopped looking at the outside picture. Thorne writes “because of the enormous difficulty light has escaping gravity’s grip, as seen from afar the implosion seems to take forever; the star’s surface seems never quite to reach the critical circumference, and the horizon never forms.” But the horizon never forms because of the gravitatiional effect on time. The light delay is an optical effect, not a real time delay.