# The Naked Scientists Forum

### Author Topic: Why do people think Relativity predicts event horizons?  (Read 18422 times)

#### jeffreyH

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##### Re: Why do people think Relativity predicts event horizons?
« Reply #75 on: 03/01/2014 20:20:41 »
Jeffrey, either one define a universe constricted, that represent a 'fish bowl'. In such a universe a Lorentz contraction still will be observer dependent though, meaning that as we have a fish bowl to go out from I can make smaller fish bowls in it, 'systems' that I limit by some mean. In my 'system' I can define as many observers I like. Each observer having a different motion relative all other observers. I can also let each observer inside that 'system' represent a different mass. Each one of those observers inside my 'system' will measure a different time dilation, and defining a Lorentz contraction as a complementary description to a time dilation, depending on frame of reference you use for your observation, there also will be differently Lorentz contracted 'fishbowls', all locally defined.

Either that is a illusion, or it is true. If it is true then using a 'fish bowl' perspective becomes very tricky, as the system you defined is observer dependent, and also as there is no frame of reference more right than any other, including the one you used defining that 'system'. One also need to acknowledge that a Lorentz contraction makes no difference between a vacuum and 'mass', for example looking in the direction one travel at a relativistic speed.

It is observer dependent.

You do realize of course that the vacuum you propose according to quantum physics is seething with Higgs bosons and elementary particles popping into and out of existence all the time.

#### yor_on

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##### Re: Why do people think Relativity predicts event horizons?
« Reply #76 on: 03/01/2014 22:20:14 »
The vacuum 'system' I describe is from Einsteins definitions Jeffrey. And QM is not relativity, although most of us, you and me too, would like for them to join together, into one description making sense. Time dilations and Lorentz contractions are existent everywhere, gravitationally and motion wise. And they are proved to exist by NIST, as well as by others, experimentally.

#### jeffreyH

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##### Re: Why do people think Relativity predicts event horizons?
« Reply #77 on: 04/01/2014 01:01:56 »
The vacuum 'system' I describe is from Einsteins definitions Jeffrey. And QM is not relativity, although most of us, you and me too, would like for them to join together, into one description making sense. Time dilations and Lorentz contractions are existent everywhere, gravitationally and motion wise. And they are proved to exist by NIST, as well as by others, experimentally.

I would agree with all of that.

#### AndroidNeox

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##### Re: Why do people think Relativity predicts event horizons?
« Reply #78 on: 18/12/2014 00:24:16 »
The October issue of Astronomy magazine presents an excellent explanation of why black holes cannot have event horizons. Looks like Einstein was right.

#### yor_on

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##### Re: Why do people think Relativity predicts event horizons?
« Reply #79 on: 19/12/2014 20:45:34 »
Think there was an idea using a definition in where no matter ever reached past that event horizon using time dilation. But a time dilation is observer dependent, several observers of a same object might give it different 'clocks', 'simultaneously'. The only case in where you prove a time dilation to exist indefinitely after is the one in where you arrange a twin experiment, as far as I can see, practically that is.

If you split 'c', using it as your local clock. Then to get to a situation in where you don't pass the event horizon, you will have to change your local measurement of 'c'. And 'c' is 'c'. That's what I understand SR to build on, that and Maxwell's equations. Can you see how I think there? To say that I can't pass that event horizon is the same as telling me that 'c' won't be 'c'. That local clock never stops, and according to that and displacements, you will pass.

#### PmbPhy

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##### Re: Why do people think Relativity predicts event horizons?
« Reply #80 on: 19/12/2014 21:04:14 »
The October issue of Astronomy magazine presents an excellent explanation of why black holes cannot have event horizons. Looks like Einstein was right.
Thanks for bringing this to my attention. I know that such claims like "there are no black holes" etc. more often than not come from crackpots and cranks. But in this case the assertion came from Steven Hawking and in Nature magazine! See: http://www.nature.com/news/stephen-hawking-there-are-no-black-holes-1.14583
Quote
Most physicists foolhardy enough to write a paper claiming that “there are no black holes” — at least not in the sense we usually imagine — would probably be dismissed as cranks. But when the call to redefine these cosmic crunchers comes from Stephen Hawking, it’s worth taking notice. In a paper posted online, the physicist, based at the University of Cambridge, UK, and one of the creators of modern black-hole theory, does away with the notion of an event horizon, the invisible boundary thought to shroud every black hole, beyond which nothing, not even light, can escape.

Event horizons are funny things. I've always been unsure about them because they can't be observed.

#### yor_on

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##### Re: Why do people think Relativity predicts event horizons?
« Reply #81 on: 19/12/2014 23:24:44 »
Maybe you read this one Pete? Alternatives, linked by Dlorde, As for which one is most close to reality I don't know, but I find Bees approach to it, as being a paradox that logically fails, interesting. I just can't make me believe in the idea of a 'firewall', https://medium.com/starts-with-a-bang/yes-virginia-black-holes-exist-df0a131d7b95

#### jeffreyH

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##### Re: Why do people think Relativity predicts event horizons?
« Reply #82 on: 19/12/2014 23:41:29 »
Well Hawking's paper was brief but very interesting.

#### The Naked Scientists Forum

##### Re: Why do people think Relativity predicts event horizons?
« Reply #82 on: 19/12/2014 23:41:29 »