Black Holes, for Eta Carinae

Hello Eta (and any others interested).This has nothing to do with Creationism, just Cosmology. Eta, you have shown that you are well versed in this area, and prepared to devote some of your time to sorting out the misconceptions of others, so I would appreciate your comments on the following.For several decades I have been studying Astronomy and Cosmology (and many other branches of science) as an intelligent layman, and have come to some conclusions which are out of line with the popular Cosmology books, New Scientist, etc.Time slows down in a gravitational field. Our clocks run slow because of the Earth’s gravity, and this has been measured using atomic clocks up in orbit, which run faster. Similarly, time would run slower for something falling into a black hole, relative to an outside, distant observer. At an event horizon, time comes to a complete standstill. Ok, that is not quite correct. Space-time becomes distorted so that time actually extends along the event horizon, and inside the event horizon, future time actually points towards the centre of the black hole.But our distant observer will see the descent of the falling object slow up, and will never see the object reach the event horizon. From his (our) point of view, nothing can ever quite fall into a black hole - it would take an infinite time! An observer falling into a black hole, on the other hand, will see our clocks speed up. He will see the sun, and then the galaxies, grow old and die during his last few moments before he reaches the event horizon (all this assumes that he can still make observations at this point).So I conclude that matter can only enter a black hole by leaving our universe - at the far end of time. This means that no matter has ever fallen into a black hole according to our time frame. It is all frozen on the edge of the event horizon waiting for our clocks to tick over to infinity. NB. The Russian cosmologists refer to black holes as frozen stars, and British astronomer Fred Hoyle called them almost black holes. But looking in from the outside, they are such a dark grey that they might as well be called black. Radiation from in-falling matter would hide anything right at the event horizon, anyway.But wait! There’s more!If you consider a collapsing star, heavy enough to collapse past the neutron star stage, then as its inner regions approach the event horizon stage, the collapse itself will slow down, and it will never quite get to the state of being a black hole.So we have a universe full of galaxies, with cores containing extremely heavy objects busy collapsing very slowly near the centre, and very violently further out, but no event horizons and no black holes. Unfortunately, our observations cannot tell the difference (yet).You can still jump into a black hole, but you leave our universe in the process.If any of you plan to shoot me down, as I am sure some of you will, please explain exactly where you think I have gone wrong.Mike.

Sorry Ringokid, but you are way ahead of us. My topic is about whether black holes really exist, or are they theoretical end-points of processes which can only be reached after an infinite time.You seem to have accepted black holes and wormholes as facts, and branched way out in speculations in a Brad Mcfall style, leaving the rest of us behind. You assume that black holes form wormholes, and that the matter entering black holes re-appears somewhere else in the universe. I am questioning whether any matter ever enters a black hole.Mike.

Thanks for the response, Percy. Nice to know I am not alone!But it occurred to me that I had better add a couple of addenda to my post, before things go wild (optimistic - probably be ignored).Firstly, I am well aware that the theory of event horizons get a lot more complicated when the black hole is spinning, as I am sure all of them are. I don't know whether this affects the issue.Secondly, there is an APPARENT time dilatation seen by the distant observer caused by the time taken for light emitted by the falling object to reach him. This is in addition to the ACTUAL time dilatation caused by the gravitational field near the event horizon. So these two effects need to be added together to account for the observations of the distant observer.Mike.

No, Percy, I am assuming that the remote observer is stationary relative to the black hole.If the object falling into the BH is emitting pulses at a steady rate (by its clock), then these pulses will get slower and slower by the observer's clock due to general relativity effects. But the pulse signals will also take longer and longer to reach the observer as the object falls deeper into the gravitational field. Each successive pulse has more gravitational field to crawl up through, and takes longer to reach the observer.This results in a red-shift like the doppler effect, but not due to relative velocity.If the object was hanging stationary above the event horizon, and not falling in, then the observer would only see the first effect, just like a spaceman in orbit observing our clocks here in Earth's gravity field.Mike.

Yes, Percy, it gets confusing, because we have Special Relativity and General Relativity effects combining here.If we didn't have General Relativity sticking its oar in, then the falling object would reach the speed of light at the event horizon (assuming it fell from infinity), and we would see normal Special Relativity time dilatation (dilation?) effects for both reference frames before this moment.But the gravitational field adds a non-relative GR effect. Contrary to Eta's post, atomic clocks in orbit HAVE been observed to run FASTER than those on the ground - after the effects of orbital motion have been eliminated. If an observer was suspended just above the event horizon by a very powerful rocket motor, and we were suspended in a similar manner, but a million kilometres away, then there would be no relative motion to bother about, and he would see us (and the rest of the universe) running fast.But if he is falling at high velocity, then SR adds its effects, and I don't know how they add up, but I am certain the GR time dilatation will slow him up just before he reaches the event horizon or speed of light.NB. Imagine an object falling through an event horizon. Just as it reaches there it reaches the velocity of light, acquires infinite mass, and sucks the whole universe in with infinite acceleration. Sorry, I don't buy it.I am working on a reply to Eta to cover this. Some research needed.Mike.

For Eta and Nosyned:Yes, the speed of light does decrease, but as Eta says, it depends on your reference frame. An observer down there with the slow light would have his clock slowed in the same ratio, so his measurement would still be c.Replying on behalf of ‘All’,There are many entries on the web describing the problems with timing GPS systems due to the GR effect, which causes clocks in orbit to tick over FASTER than those down here - by 442.5 parts in 10**12, or 45 microseconds per day.A couple of references that I looked up are
http://www.phys.lsu.edu/mog/mog9/node9.html
Page Not Found | PhysicsCentralSome other references for the time effects near an event horizon (quotes from 'authorities') -If the observer follows a stone falling into a black hole, he will find that close to the Schwarzschild sphere the stone starts to ‘decelerate’ and gets to the black hole boundary only after an infinitely long time
A distant observer will see a similar picture in the very process of generation of a black hole, when the stellar matter is pulled by gravitation towards the centre. For this observer, the surface of the star takes an infinitely long time to reach the Schwarzschild sphere as if stalling at the gravitational radius.
The red shift due to time dilatation caused by a strong gravitational field is aggravated by reddening due to the Doppler effect.
Igor Novikov Black Holes and the UniverseAs Betty hovers closer to the Schwarzschild radius, so the timewarp grows ever larger. She will see Ann’s clock racing faster and faster ahead of her own. ..... But, although in principle Ann from afar would see events in the spaceship running very slowly, in practice she has a hard time seeing anything at all, because of the spiralling red shift.
...what looks like a black hole is in reality a star frozen in the very late stages of collapse. But all the properties of this collapsing star become very rapidly (typically in milliseconds or less from the onset of collapse) indistinguishable from a genuinely empty, already-formed black hole.
This means that, in the few microseconds that Betty takes to whiz across the horizon, all of eternity will have passed by outside. The fast-forwarded images will accelerate to infinite speed. Betty will know, once inside the black hole, that the universe outside is ‘over’, even if it has lasted forever.
Paul Davies About Time... the star’s implosion, as seen by a stationary observer who remains outside, would slow and ultimately freeze as the star’s surface approached the critical Schwarzschild circumference.
John Preskill and Kip S. Thorne in Forward to Feynman Lectures on Gravitation.Is that enough to back up my claim that there is a GR time dilatation in addition to Special Relativity effects, and this is a slowing down of clocks near the event horizon, and not simply a red-shift due to the light taking longer to reach us; and also that the observer in the strong gravitational field will see the clock of the remote observer running fast?Mike.

Well, you have presented me with a lot of contrary views, but have not provided evidence that my interpretation is wrong.Eta, in message 16 you said:
No, the observer falling through the event horizon does not see the universe age - he sees their clocks run slow just as they see his clock run slow.but when I said in message 17
But the gravitational field adds a non-relative GR effect. Contrary to Eta's post, atomic clocks in orbit HAVE been observed to run FASTER than those on the ground - after the effects of orbital motion have been eliminated.you responded in message 20 with
You jumped the gun and assumed something I did not say
Of course a clock runs faster in a plane at higher altitude than lower altitude.Do you accept that an observer in Earth’s gravitation field sees the same speeding up (blueshift) in an orbiting clock as an observer hovering above an event horizon observing a remote clock? Is there just a confusion because of the relative velocity of a falling observer?Thank you, cjhs, for referring me to that interesting website Page Redirection
Fascinating animated diagrams. Must have taken an age to set it up. I will have to spend some time on it to get a feel for Kruskal-Szekeres coordinates. But it does support my arguments, as per the following extracts from some paragraphs -Gravitational slowing of time
This time dilation factor tends to zero as r approaches the Schwarzschild radius rs, which means that someone at the Schwarzschild radius will appear to freeze to a stop, as seen by anyone outside the Schwarzschild radius.Gravitational redshift
That is, an outside observer will observe photons emitted from within a gravitational potential to be redshifted to lower frequencies, or equivalently to longer wavelengths.
Conversely, an observer at rest in a gravitational potential will observe photons from outside to be blueshifted to higher frequencies, shorter wavelengths.That the redshift factor is the same as the time dilation factor (well, so one's the reciprocal of the other, but that's just because the redshift factor is, conventionally, a ratio of wavelengths rather than a ratio of frequencies) is no coincidence. Photons are a good clocks. When a photon is redshifted, its frequency, the rate at which it ticks, slows down.So a hovering observer near an event horizon will see remote light blueshifted, which means that remote clocks run fast (just as observed by GPS systems), and the outside universe appears accelerated. You cannot separate these effects - they are all the result of General Relativity time dilatation.Schwarzschild Spacetime Diagram
Unfortunately, I could not cut and paste this diagram, but if you have a look at it you will see that all the light ray world lines approaching the event horizon curve upwards and approach it asymptotically - they never reach it. The exact same thing applies to the world lines of any object falling in - it never reaches the event horizon (or does after an infinite time, if you like). So, in our time frame, where time in measured by our clocks and calendars, nothing has ever fallen into a block hole, and nothing ever will.Eta, you say that the event horizon has no physical reality, but it defines a volume from which no light can escape into the outside universe. Surely that is a physical reality!Cjhs, you say that it all depends on the metric, and
a falling object itself certainly passes through the event horizon without dramas, and reaches the central singularity within a finite time
Of course you can fall into a black hole. There is nothing to stop you. In fact, the fall is almost instantaneous - but by your clock, not ours. But in OUR universe it never happens. You have to remember than we have two observers, with very different space and time coordinates. I don’t care if he meets up with angels and fairies on the way, it doesn’t happen in our universe.No changing of metrics will allow light to pass out through an event horizon. We only have our clocks and metre-rules. Whatever metric we are in, we are stuck with it. I have never seen a clock calibrated for Kruskal-Szekeres coordinates, which look even worse than a logarithmic scale!I am sorry if I seem obtuse to you, but neither of you have produced anything to contradict my views yet. Many thanks for the time you have devoted to this cause.Mike.NB. How does one use italics, boldsface, etc in these posts? I can't find any options![This message has been edited by Mike Holland, 01-30-2004]

Thanks Asgara. I have edited my last post, and set up all the pasted quotes in italics. Much better. There will be no holding me back now.
Mike.

Thanks for your time and effort, Eta. I am not serious about the falling observer actually seeing the universe fade and die, because it happens in the last billionth of a second (by his clock) before he passes the event horizon.
But please have a look at the diagram on the website referred to by cjhs. It shows the paths of light rays curve up and approach the event horizon asymptotically. This is exactly the point I am making. Light rays never reach the event horizon (in our universe), and neither do falling objects. A falling object would be moving slower than light, so its world-line would be more vertical than those of the light rays. As it approaches the event horizon light rays will keep intersecting its worldline, and it 'sees' light approaching it from the outside universe for the rest of (our) time, but all in an instant in its time.Mike.

Sure, you could choose a metric with a time scale based on the reciprocal of our time. Then the object passes the event horizon at "time" zero. So what! If you look at those other diagrams you will see that time for us is no longer linear. In fact, as I remarked, one looks worse than logarithmic.The point is, using these metrics, our clocks still read infinity when the object reaches the event horizon. The metrics do not change this fact. They simply distort the picture.Mike.

Cjhs, you seem to have a conviction that all my concerns can be resolved by considering alternative metrics. You seem to think that event horizons have no real existence, and are theoretical constructs of particular metrics. This is wrong. Matter does not escape from a black hole, in any metric.Let me try and handle your points one at a time:What you call "facts" are relative to your chosen co-ordinate system; not absolute statements about spacetime. Your terms are not defined. What do you mean by "when" the object reaches the event horizon? For this statement to make sense, you need to have some kind of relationship between times in different locations in space. But there is no absolute relationship of this kind; and metrics emphatically do not distort the picture. What could that even mean?So when we look at a Schwarzschild spacetime diagram, it is a ‘fact’ that light approaches the event horizon asymptotically, but when we look at an Eddington-Finkelstein diagram we see the ‘fact’ that light goes up the diagram at 45 degrees and crosses the event horizon. Fine. I have no problem with this. It is like the old conundrum ’Do parallel lines never meet, or do they meet at infinity?’.I see that Finkelstein time is given by
F = t + ln(r-1), so at the event horizon r =1, and F = t + ln(0) = t - infinity!
So the point where Finkelstein time shows a falling object crossing the event horizon is the point where our clocks read infinity. So we agree. A change of metric does not change the facts; it only changes the figures you use to describe them.But I have a problem with that metric because my wristwatch it not calibrated for Finkelstein time.The distortion is the claim that there is some kind of absolute which the metrics are distorting. That appears to be your error in a nutshull. There is no one correct metric; and you can pick your metric and do appropriate transforms from one set of co-ordinates to another. It is all still the same spacetime.As I pointed out above, a change of metric does not change the facts. But you are the one proposing to solve the problems by a change of metric. This is your error in a nutshell. Refer to your own first post on this topic:
The perception that things can't fall past the horizon is an error about what the metrics mean. A common metric (the Schwartzschild metric) diverges at the Schwartzchild radius. There are other metrics which are better suited for tracking what happens to an infalling object, such as the Kruskal-Szekeres metric, obtained by a suitable co-ordinate transformation, which also removes the divergence. In any case, a falling object itself certainly passes through the event horizon without dramas, and reaches the central singularity within a finite time.
So you propose to resolve the problem by choosing a more suitable metric!The Schwartzchild metric has a singularity at the event horizon. However, there is no special privileged status for that metric; and the discontinuity is a property of the metric; not a break down in relativistic physics. For a sufficiently large black hole, a spacecraft flying though the event horizon would not notice any special discontinuity or sudden effect as they fly past the point of no return.Yes and no! I have always accepted that the infalling observer would not see any space or time deformities, but the Schwarzschild diagram agrees with me that he would see a sudden effect if he looks back at the outside universe, because of the relative time dilatation. I have not analysed the other metrics in this regards, but if they disagree then we have a problem.Have another look at the Schwarzschild diagram. All those outside light rays curve upwards, but as the observer would be falling more slowly than light, his worldline would be more vertical, and all approaching light rays would intersect his worldline, for the rest of forever up the diagram. If you disagree with this reading of the diagram, please explain why. And if any of the other metrics give a different result, we have a problem.For an outside observer, there are various ways (metrics) they might choose to apply co-ordinates to the space. With a suitable transform to more appropriate metrics (more appropriate for discussing what happens as an object falls through the event horizon) there is no singularity or discontinuity. And there is most certainly no absolute basis for matching up events in different locations as being "simultaneous".Did I say ‘simultaneous’? Well, I suppose I implied it by talking about the clock of an outside observer when something happens at the event horizon.The singularity which appears at the center of the black hole is another thing entirely. That singularity appears in all the metrics, and it indicates that our current relativistic physics breaks down at the central singularity. We will need a better physical model (a mix of quantum mechanics and relativity) to describe that point in space.
But the event horizon presents no such problem. It is described just fine with classical relativistic physics, and there is no reason to think anything special is going on at the event horizon which breaks existing physics.But these are exactly the problems that my view resolves. I do not believe anything special is going on at the event horizon - I do not believe that objects falling from infinity would reach the speed of light there and acquire infinite mass; I do not believe in a total time dilatation where time comes to a complete stop (in any metric or reference frame); I do not believe in a singularity at the centre where the laws of physics break down. It is you guys who believe in all these weird things.Have another look at my original post. My position is that the slowing of time as gravity increases means that these situations are never quite reached, however close conditions may approximate to them. I propose a universe with no such absolutes or singularities or breakdowns of physics. And I hold that this is the universe implied by Einstein’s theories.Mike.

Ye Gods! So it has come to this! You plot to accuse me of being a crank, and have me arrained and publicly flogged or worse!
But all I ask is that you put your eye to the eyepiece.I looked through those articles/movies about what is seen as you approach and pass through an event horizon, and found them fascinating. But not much new to me. I have no problem with anything said there, except the author's answer to question 2 - that there is no blue shift/speeding up of the world behind you just before you pass the horizon. We see the speeding up when we look at orbiting sattelites, so why wouldn't we in tis stronger gravitational field? The only reason I can think of is that the opposite effect is introduced by the velocity of our fall. Eta Carina said he would calculate the net effect, but he has the problem of what velocity to assume for the falling observer. The observer could go in slowly with his retro-rockets firing all the way! Anyway, I am certain that the GR effect will dominate at the end.

Sheesh... Yes, I do resolve the "problem" of infinite time at the event horizon by choosing a metric where time is not infinite at the event horizon. So does anyone else who knows physics. If you don't even recognize that, I can't help you.

What do you mean by a metric where time is not infinite? In the Finkelstein-Einstein metric the Finkelstein time is our time minus infinity at the event horizon. So you can do anything you like with these changes of metric. Why not choose a metric where time is minus our time. Then you can say that the falling observer passed through the e.h. before he started falling, and that PROVES that it happens!Going back to that Schwarzschild diagram in your first reference (yes, I am choosing a metric which shows my point best, but is just as valid as other metrics), one can add the world-line of the observer - just to the right of the red line of the e.h., but not sloping as much as the light rays, because he is falling more slowly. Then you can see that the light rays all eventually arrive at his world line - he 'sees' them. And no matter how far you go up the diagram he keeps 'seeing' them - through the future of the universe.These light rays (photons) hitting his worls lines are events which happen. Can you make them unhappen by changing metrics? I don't think so. You can only change the space and time coordinates used to record them, but the events remain. He 'sees' the future of our universe.If you want to call me a quack, feel free. I am in very good company on this one. Sticks and stones and all that. In fact I will give you some extra ammunition. I am very partial to the observations and interpretations of Halton Arp regarding quasars and perculiar galaxies. And I also have Hoyle, Burbridge and Narlikar's book 'A Different Approach to Cosmology' in my library, 'though I don't like their cosmology.Cheers, Mike.
And thanks again for digging out those fascinating web sites.

Where else is (was) there? There was no other space/place.If you picture the Big Bang as an explosion in pre-existing space, then the universe must have started off as a black hole, and it would still be a black hole - expansion against the mass/gravity of the whole universe would be impossible.But if you imagine it as space expanding, taking everything with it, them you are imagining things, because I don't believe anyone can really imagine it. We can do the maths, 'though.Mike.

Chris, I am taking this in good humour. Refer my comments at the start of my previous post regarding being flogged or worse!Thanks for those two equations for a falling light ray and a falling body at 0.5c. OK, they have convinced me that only a limited set of 'later' light rays would reach him before he reaches the event horizon. So he will see a little blue shifted light, but not the whole future of the universe. I am still putting figures into those equations to get a better feel for what happens. It seems crazy that he takes forever to reach the event horizon (in a Schwarzschilkd metric), and the light is travelling twice as fast (at least in normal space), but it doesn't catch up. Something like the tortise and hare paradox.Obviously if he were stationary, he would see the whole future (but no blue shift). I will try lower velocities for the observer, to see where it changes.But I still disagree with Eta - Yes you observe an object falling in to slow down (and get redshifted) BUT the object in reality fell in long ago.But then if what you say about choosing a metric to allow you to talk about the time at a remote place is correct, then either/neither of us is 'right'.Regarding Arp and other misfits, don't be so hard on them. Sometimes the 'cranks' are right, eg. Peter Wegener and continental drift. And there is plenty of room for speculation when current theories propose that the universe is 90% dark matter, that we know nothing about as yet! I also like the Aquatic Ape theory of Elaine Morgan and co. Much more fascinating than the standard theories of human evolution.Mike.