JEROME - Black holes do not exist

[lupus_in_fabula]

A Black hole eating: NASA Telescope Sees Black Hole Munch On A Star. Bon Appétit!

Funny how the relevant questions regarding black holes don’t pertain them existing, but rather about the degree of precision in measuring them and the precise effect they have on their surrounding.



Of course, if you keep your fingers in your ears and your eyes shut, and completely ignore what's happening in the field of astronomy, I suppose it's possible to be completely clueless.

 

[Reality Check]

Well, there has to be some form of quantum gravity, right? If and when we find out what it is, it will make both special and general relativity redundant.

It depends on what you mean by redundant.
Newtons laws of motion are still used in calculations. Newtonian gravitation is still used in calculations. So they are not redundant in the sense of not being used anymore. A quantum gravity theory is likely to be complex and so used where quantum mechanics and general relativity are not applicable.

 

[rats]

Possible derail...

Do any knowledgeable folk here know what this announcement on Chandra's web site is all about?

NASA will announce the discovery of an object in our Galaxy astronomers have been hunting for more than 50 years. Tune in on May 14, at 1 p.m. EDT.

My guess would be Sagittarius A*

Very exciting!

 

[Gurdur]

Just a small note -- when it is said here that Special Relativity cuts out FTL speeds, AFAIK SR only forbids the transmission of information at FTL speeds. Therefore non-informational tachyons still can exist?

Just asking.

 

[sol invictus]

Unless quantum gravity is correct, at which point general relativity only reduces to special relativity on scales that are neither too large nor too small. In any case a theory that is merely a useful approximation of another theory is a poor tool to be ruling anything out.

String theory is a theory of quantum gravity. It is explicitly Lorentz invariant.

General relativity has as its underlying principle the symmetry of general covariance. As I said above, because every non-singular manifold is locally flat, a generally covariant theory on a non-singular manifold is locally Lorentz invariant. A non-generally covariant theory would not be a theory of quantum gravity.

Lorentz invariance has been tested experimentally to extremely high precision in many different ways.

So we can be very confident that ftl motion is impossible.

 

[sol invictus]

Therefore non-informational tachyons still can exist?

Any transmission of energy or information ftl is impossible. Still, some "things" can move faster than c: shadows, the intersection point of the two blades of a scissors, something pre-arranged to collapse all at once.

 

[GreyICE]

String theory is a theory of quantum gravity. It is explicitly Lorentz invariant.

General relativity has as its underlying principle the symmetry of general covariance. As I said above, because every non-singular manifold is locally flat, a generally covariant theory on a non-singular manifold is locally Lorentz invariant. A non-generally covariant theory would not be a theory of quantum gravity.

Lorentz invariance has been tested experimentally to extremely high precision in many different ways.

So we can be very confident that ftl motion is impossible.

You're supposed to end posts like this with [/handwave]

You just simplified an extremely complex subject to your particular side without giving a great explanation why.

P.S. A Plank length is VERY EXTREMELY small. Also, I can use more font tags than you.

 

[aggle-rithm]

Just a small note -- when it is said here that Special Relativity cuts out FTL speeds, AFAIK SR only forbids the transmission of information at FTL speeds. Therefore non-informational tachyons still can exist?

Wouldn't non-informational tachyons be indistinguishable from nothing?

If we could detect them at all, then they would be conveying information.

 

[Upchurch]

I know precisely what redshift is and is not - if I didn't know what it was I wouldn't be qualified to teach college-level physics & astronomy courses on the topic.

Whoa, there's your problem. You're part of the system, man. It's your job to keep free-thinkers like Jerome down, man, with all your facts and actual knowledge on the subject.

What happened to you? You used to be cool.

 

[Diagoras]

Any transmission of energy or information ftl is impossible. Still, some "things" can move faster than c: shadows, the intersection point of the two blades of a scissors, something pre-arranged to collapse all at once.

Wouldn't that break your scissors though?

Seriously though, I never really thought about it, but that makes sense if the two blades are approaching each other at speeds near c. Isn't science neat?

 

[sol invictus]

You just simplified an extremely complex subject to your particular side without giving a great explanation why.

No, I simply stated a series of facts.

If you want further explanation of them or their implications, ask politely.

 

[GreyICE]

No, I simply stated a series of facts.

If you want further explanation of them or their implications, ask politely.

Okay. Please explain the potential implications of you handwaving Lorenz invariance into being absolutely proven to levels of 'very certain' without any discussion.

Also, can I inquire how the words "string theory" and the words "very certain" belong in the same post?

 

[sol invictus]

Okay. Please explain the potential implications of you handwaving Lorenz invariance into being absolutely proven to levels of 'very certain' without any discussion.

I didn't even use that phrase.

What we know, experimentally, is that if Lorentz invariance is violated it is at an incredibly small level. The precise numbers depend on which form the violation takes, but the limits are extremely good on any possible term. You can find many reviews and discussions of the experimental limits on the web with a little searching.

Also, can I inquire how the words "string theory" and the words "very certain" belong in the same post?

You made the (false) claim that quantizing gravity induces violations of Lorentz invariance. I provided a counterexample.

 

[Ziggurat]

Wouldn't non-informational tachyons be indistinguishable from nothing?

Indeed. They're a bit like pickle-worms: a parasitic worm that infests pickles, eating them from the inside out until only the pickle worm is left. The pickle worm is deceptively shaped and colored just like a pickle, until the hapless victim bites into it, and which point they notice that the pickle worm tastes just like a pickle too.

What, you don't believe pickle worms exist? Try to prove it!

 

[Morrigan]

I hate pickles, so I'm safe, at least.

 

[aggle-rithm]

Indeed. They're a bit like pickle-worms: a parasitic worm that infests pickles, eating them from the inside out until only the pickle worm is left. The pickle worm is deceptively shaped and colored just like a pickle, until the hapless victim bites into it, and which point they notice that the pickle worm tastes just like a pickle too.

What, you don't believe pickle worms exist? Try to prove it!

I've seen their offspring, which look identical but are smaller and are impaled by toothpicks.

 

[arthwollipot]

It depends on what you mean by redundant.
Newtons laws of motion are still used in calculations. Newtonian gravitation is still used in calculations. So they are not redundant in the sense of not being used anymore. A quantum gravity theory is likely to be complex and so used where quantum mechanics and general relativity are not applicable.

But technically speaking, Newtonian mechanics are redundant because you can achieve exactly the same result in non-relativistic frames by using Einsteinian mechanics. They are functionally identical. You could say that you can simply ignore the bits of Einstein that deal with high velocities or huge gravitational fields and you have Newton.

Einstein supercedes Newton by including it. Newton is redundant when you've got Einstein, although it has to be said that Newton is easier.

 

[GreyICE]

I didn't even use that phrase.

What we know, experimentally, is that if Lorentz invariance is violated it is at an incredibly small level. The precise numbers depend on which form the violation takes, but the limits are extremely good on any possible term. You can find many reviews and discussions of the experimental limits on the web with a little searching.

Yes, but that merely sets a limit on how small the variations are, based on current instrumentation. We're still unable to see a lot of things that we think should exist, so I'm not convinced that that's the scale we need to be looking at.

You made the (false) claim that quantizing gravity induces violations of Lorentz invariance. I provided a counterexample.

Okay, many theories induce violations. String theory doesn't, but string theory is also a load of horse byproduct. If it's true, then absolutely everything we though we knew about science is wrong, starting with "Theories need to be empirically testable, and designing a theory that cannot be tested and then hypothesizing with it is bad science" and moving on from there.

 

[sol invictus]

Yes, but that merely sets a limit on how small the variations are, based on current instrumentation.

Yes - obviously. Science isn't about proof, it's about evidence, and the evidence for exact Lorentz invariance is extremely strong.

Okay, many theories induce violations. String theory doesn't, but string theory is also a load of horse byproduct. If it's true, then absolutely everything we though we knew about science is wrong, starting with "Theories need to be empirically testable, and designing a theory that cannot be tested and then hypothesizing with it is bad science" and moving on from there.

What utter and complete nonsense. String theory is certainly empirically testable - it's just hard, because the standard model plus classical general relativity is a very, very, very good approximation to it (at least that's the case in most versions of it - there are some versions that the LHC will test directly). In a sense, every test of gravity is a test of string theory - just not one that distinguishes it from some other (so far non-existent) theory of quantum gravity.

Moreover it's the only theory of quantum gravity around, so for general questions (like whether quantizing gravity necessarily violates Lorentz invariance) it's the best guide.

Question - why are you making declarative statements on topics you obviously do not understand?

 

[Upchurch]

I'm all for giving people time to respond. None of us are online 24/7 ...yet.

However, it has been four days, including a weekend, since Jerome has posted in the thread. That seems to me to be outside his normal posting habits. And the last time he did post, he ignored the questions posed to him entirely.

Are we to take that as a concession of the point (that, indeed, there is evidence that Black Holes exist) and that, therefore, the original topic of the thread is now dead or what?