Are Black Holes Real or Just Theoretical Constructs?

[Bariyon]

From the Einstein gravitational equations comes the Schwarzschild solution, which predicts the existence of black holes.

What if the Schwarzschild solution is just an approximate expression, meaning that the Einstein equations are also approximate?

Then black holes no longer exist, colossal amounts of time have been wasted by foolish priests calculating the number of angels on the head of a pin and other silly calculations, and the entire physics church directs its embarrassed anger at the person who would dare to suggest such outrageous blasphemy, in order to save its arse and regain the bleeting praises of the sheep flocks?

 

[chroot]

No scientific theory is ever proven, and it's entirely possible that general relativity is completely wrong. However, for now, every experiment that has ever been performed agrees with its predictions. That's really all we can ask of a theory.

As far as your "physics churches" and "outrageous blasphemy" and all that nonsense: no scientist will ever be mad at another for proposing a theory which is later falsified -- even if that theory stood up to scrutiny for hundreds of years first. Falsifying a theory is every bit as useful as finding new support for a theory. That's how science works.

Perhaps you'd be surprised to learn how many physicists would absolutely love to disprove a theory as well-supported as relativity? It would mean an instant Nobel Prize, instant fame, and a spot at the top of the list of the most important scientists to have ever lived. At the same time, a scientist that disproves Einstein will surely not feel anger toward him: by any account, he did fantastic work.

- Warren

 

[Janitor]

I'll bet physicists are relieved that astronomers have been finding some evidence for ultra-massive black holes in galactic centers. That means that it probably hasn't been a purely academic exercise. I'm about half sure that I once read that Einstein himself thought black holes were probably something nature would never create. That might have been in response to a paper by Oppenheimer (and Volkoff? or somebody who co-wrote it) back in the years prior to WW II.

 

[Point_Particle]

I think perhaps you are taking the wrong approach to the interpretation of calculations in physics. It is rare that in modern physics, (which often involves very messy and difficult to solve differential equations) approximations aren't involved in the development of a model. For example, there are only three fully solved problems in quantum mechanics, but that does not necessarily preclude the broad applicability of it as a predictive mathematical model for physical reality, a model whose predictions can be corroborated by experiment and observation. There is something left behind after the death of a super massive star, something with an intense gravitational field and the tendency to shoot jets of high energy photons from its magnetic poles, and physicists call this thing a black hole.

The theory of "black holes" was around long before Einstein, mind you. Newton toyed with the idea of a gravitational field so strong that not even light can escape, but his formulation violated the accepted constancy of the speed of light, so it has fallen by the wayside. There is no reason that black holes should make intuitive sense - many things in physics do not. This is because the validity of a theory isn't gauged on how closely it resembles the way physical reality actually is, its validity is gauged on the precision and fecundity of the predictions it makes, that is, how many of its predictions can be compared with observation, and how closely those predictions coincide with what we can measure.

Your juxtaposition of science and religion is fundamentally flawed for at least one good reason. Science and religion are predicated on two entirely disparate foundations. Science is based on falsifiability and observation, while religion is based on piety and immutable axiom.

 

[Janitor]

I've got to ask-

there are only three fully solved problems in quantum mechanics- Point Particle

Would that be single particle in a box, simple harmonic oscillator, and single particle in a spherically-symmetric potential?

 

[Point_Particle]

Would that be single particle in a box, simple harmonic oscillator, and single particle in a spherically-symmetric potential?

Indeed, although my professor discussed the latter contextually, with the H atom.

 

[HallsofIvy]

From the Einstein gravitational equations comes the Schwarzschild solution, which predicts the existence of black holes.

What if the Schwarzschild solution is just an approximate expression, meaning that the Einstein equations are also approximate?

Then black holes no longer exist, colossal amounts of time have been wasted by foolish priests calculating the number of angels on the head of a pin and other silly calculations, and the entire physics church directs its embarrassed anger at the person who would dare to suggest such outrageous blasphemy, in order to save its arse and regain the bleeting praises of the sheep flocks?

Yeah, and a lot of people have wasted time actually LEARNING things- something I exect you would never be guilty of.

The Schwarzschild equation, like any equation in physics, is just an approximation just as the "Einstein equations" are only approximations. However, it is well know that black holes can exist in any theory that approximates the Schwarzschild equations.

I do hope that won't keep you from showering the rest of us with invective! (I'm pretty sure it won't.)

 

[russ_watters]

Taking a different view: black hole were predicted by the equations. The properties were well established and quite a lot of predictions were made about them through mathematical derivation alone.

Then, several decades later, the Hubble telescope was launched. It found regions of space which contained phenomena that fit the predicted properties of black holes. By definition, they are black holes.

Our understanding of what "black holes" are may yet (read: will) change, but we have found black holes. They do exist.

 

[Bariyon]

Chroot,

You seem to be painting a picture of an amiable community of people who openly accept any contributions towards greater understanding. I simply don't believe it. I'm aware that many physicists would love to make a significant contribution to physics. But why? Fame, an instant professorship and the ability to nap for the rest of their life? Well, Einstein did it after all. But if you're searching for true knowledge, you should not expect any popularity whatsoever. How are you going to react when new scientific understanding arises that speaks of the same things that the ancient prophets spoke of?

Janitor,

The inferred existence of black holes from observation tells us little about the validity of Einstein's equation. This is the most important thing - to develop a correct theory of gravity - and no amount of peering into the distance through a telescope is going to achieve this.

Point Particle,

A model is usually known to be approximate, so it has some predictive power, but it should not be pushed too far. However Einstein's equation is often treated differently. It is viewed as expressing a fundamental truth, all of its implications are explored extensively, its mathematical structure is examined extensively. The study of black holes has become an industry of its own. If only physicists spent as much time examining the validity of Einstein's equation as they did calculating the various properties of black holes! And if you tell me that calculating the properties of the equation is effectively testing it, then I reply that it hasn't been very successful so far.

The older I get, the more science comes across as a foolish religion. If you look down on ancient wisdom and the way it has developed, then the people of the future will look down on physics and the way it is developing in front of our eyes.

HallsofIvy,

And how do you learn? By immersing yourself in accounts of what other people have thought? Is that how Einstein learned about general relativity?

Schwarzschild gave us a solution, not an equation. It is an exact solution of the Einstein equation. Please explain yourself when you claim that the Einstein equation is an approximation.

 

[chroot]

You seem to be painting a picture of an amiable community of people who openly accept any contributions towards greater understanding. I simply don't believe it.

You're welcome to believe whatever you wish; it appears you don't know many physicists, and thus speak speculatively about their behavior. I know many, and speak from experience. Many laypeople have the idea that scientists believe in theories like a religious zealot belives in a deity, but that's quite simply not so. Every physicist is aware of the limitations of theories. General relativity has its domain of applicability -- it is not applicable everywhere, and disagrees with quantum mechanics. General relativity is not the complete story, and every physicist on Earth will happily explain to you that it's not.

But if you're searching for true knowledge, you should not expect any popularity whatsoever. How are you going to react when new scientific understanding arises that speaks of the same things that the ancient prophets spoke of?

If you're suggesting that scientists should not be human, you probably need to go find a new planet and a new species of scientists.

The inferred existence of black holes from observation tells us little about the validity of Einstein's equation...no amount of peering into the distance through a telescope is going to achieve this.

Experiment is the single arbiter of success in science. You can play gedankens all day long, but if it disagrees with experiment, it's just wrong. Experiment is the single most important endeavor in science. There is no way a correct theory of gravity can ever been developed unless many, many hours are spent peering through telescopes. A correct theory of gravity will describe this universe properly. The only way to know that a theory of gravity is correct (or incorrect) is to observe this universe in detail to see if the theory describes it properly. You seem to have a malformed concept of the scientific method. I will reiterate it for you, in its essence:

1. Form a hypothesis (theorize).
2. Examine the hypothesis with experiment.
3. Draw a conclusion about the validity of that hypothesis.

It is viewed as expressing a fundamental truth

Once again, you paint caricatures of science and scientists. No physicist will ever tell you that general relativity is a fundamental truth. We know it is wrong sometimes!

If only physicists spent as much time examining the validity of Einstein's equation as they did calculating the various properties of black holes! And if you tell me that calculating the properties of the equation is effectively testing it, then I reply that it hasn't been very successful so far.

How has it not been successful? How else should we test it?

The older I get, the more science comes across as a foolish religion. If you look down on ancient wisdom and the way it has developed, then the people of the future will look down on physics and the way it is developing in front of our eyes.

Your feelings are not uncommon, and they're expressed here by laypeople quite frequently. They are not realistic, however. I assume you know very little science, and don't have any scientist friends. You probably see the scientific establishment as an evil entity conspiring to suppress the truth. I suggest you seek psychological counseling for these feelings -- I'm being completely serious, and don't mean to offend. The real world is actually much more beautiful than the one you've chosen to believe in.

And how do you learn? By immersing yourself in accounts of what other people have thought? Is that how Einstein learned about general relativity?

Much of a scientists' time is devoted to understanding other people's work. It is critical to understand the work that precedes yours, regardless of whether or not that work turned out to be correct or incorrect. There's no sense in making the same mistake twice, after all.

And yes, in fact, Einstein knew quite a lot of other peoples' work before creating his own theories. He certainly didn't invent differential geometry, or Maxwell's equations, or even the Lorentz transformation. Other scientists came up with 95% of the tools and techniques of relativity theory before Einstein. Einstein was just the first person to see that they all clicked together like puzzle pieces. If you're implying that Einstein worked in an intellectual vacuum, you seriously need to go read some history books.

- Warren

 

[Bariyon]

Chroot,

You seem to be making many assumptions about me. You are not displaying good scientific method. If you want to find out whether I'm a layperson or not, then you should ask me.

<<General relativity is not the complete story, and every physicist on Earth will happily explain to you that it's not.>>

This is a rather sweeping statement.

<<Experiment is the single arbiter of success in science.>>

I don't need a lecture on the scientific method. I could tell you about prejudices based on observation that have been expressed in scientific theory, so in this sense we should distance ourselves from observational evidence. But you're probably not prepared to listen to someone who you have already branded a religious zealot who needs psychological counselling.

<<How has it [calculational testing] not been successful? How else should we test it?>>

It has not been successful because it has not disproved general relativity yet. To test general relativity, I suggest that you adopt simple reasoning, rather than detailed calculation. Do you assume that finding a unified theory of physics is a hard thing?

<<Much of a scientists' time is devoted to understanding other people's work.>>

If scientists spent more time pursuing their own thoughts, they would probably be more successful in developing a unified theory.

<<If you're implying that Einstein worked in an intellectual vacuum, you seriously need to go read some history books.>>

Did you get my point or not? I think you did, but you're just being unamiable.

 

[FZ+]

It has not been successful because it has not disproved general relativity yet. To test general relativity, I suggest that you adopt simple reasoning, rather than detailed calculation. Do you assume that finding a unified theory of physics is a hard thing?

Forget about lectures on the scientific method. You need a lesson on inductive and deductive logic. Or else return to your ancient wisdom and stop using this stupid computer thing which your delightful ancient wisdom tells us should not exist.

 

[chroot]

And we'll just sweep this one off to TD. I've said my piece.

- Warren

 

[matt grime]

How about this perspective as to why people study religiously the implications of the theory, whatever it may be:

from deductive reasoning we may decide what the theory implies, if at some later date the observed data conflict with any of the deductions then the theory is wrong (or the deductive reasoning in it, or the observed data...)

If we didn't look at what the theory implied and compare it to our observed reality then we would be just accepting things in blind faith.

That is why we *should* presume that the theory is correct, to see if something it implies is inconsistent too.

If you were to read about the quantum research in, say, topological quantum field theory and quantum gravity, rather than looking at something that is experimentally validated by all observed data so far, then you might see how scientific research moves along better.

Part of the problem is that the technical requirements needed to test Einstein's theory are only just being met. Look at the satellite about to be launched, and look at its technical specifications. Off the top of my head I seem to remember that the tolerances mean that the gyroscopes are centred on their axes to within millionths of a milimetre and rotate at 10,000 rpm. Perhaps when the expeiment is finished in several months we will see how great Einstein is.

 

[russ_watters]

It has not been successful because it has not disproved general relativity yet.

Wow. All evidence we have affirms it, yet you still somehow know its wrong? Wow.

Bariyon, different people have different worldviews. The scientific worldview is what chroot described in his post. Though it works for a lot of people, it isn't for everyone. The philosophical or religious worldview provides answers some people haven't found in science. Its fine if you prefer that, but don't ever think they can be applied to the same questions. They cannot. Mis-applying science to philosophical questions or philosophy to questions of science will yield the wrong answers.

 

[Bariyon]

I find it quite amusing.

I presume that you are all looking for a unified theory of physics, but in doing so you are rejecting the very one you should be accepting. No wonder you find a unified theory so elusive.

You seem to be unable to accept different points of view. I mention that science will eventually become one with ancient wisdom, and I am demonised. Well you seem to have very low respect for your ancestors, and some others who are around you.

What is so strange in saying that science needs to become more integrated with philosophy and ancient wisdom (for want of a better term)? The really strange thing that has occurred is that they split in the first place, and that some people are contented with this situation.

I suggest that if you really want to learn about the real world, then climb out of your little physics haven where you residing so comfortably, and look around. Any club that greets a stranger with such antagonism has some desperate internal problems. You have far more in common with the religious groups that you despise than you care to admit.

For those of you who tell me that the Einstein equation is right, why do you believe an equation that gives rise to singularities (at the Schwarzschild radius) and predicts motion faster than the speed of light? These would ordinarily be two very good reasons for discarding the equation., Yet several physicists have invested their entire career into its study.

Star trekking across the universe... It may be fine for some, but some of us are more interested in true reality outside the physics sanctuary.

 

[matt grime]

why should we offer someone any time if they are single mindedly intent on rubbishing without substantiation theories he evidently doesn't understand?


"For those of you who tell me that the Einstein equation is right, why do you believe an equation that gives rise to singularities (at the Schwarzschild radius) and predicts motion faster than the speed of light? These would ordinarily be two very good reasons for discarding the equation., Yet several physicists have invested their entire career into its study."

why would that be a problem?

what unified theory? apart from some pathetic trolling (and that is based on the relative acheivements of others) you've n ot actually offered one single shred of evidence for any of your statements.

 

[Bariyon]

Matt grime,

Please explain yourself when you claim that I evidently don't understand the theory of relativity. Perhaps you evidently don't understand me.

The things I am saying may differ from accepted wisdom. There is a difference between that and misunderstanding the theory. But if you trust the books you read more than you trust your own mind, you would be unable to discern what is correct and what is not.

An equation that is claims to be relativistic yet predicts speeds faster than the speed of light is full of holes. If this is not sufficient evidence for refuting general relativity, then I suspect that nothing will be for you, except the word of a famous physicist who you can stand behind. So are you looking for knowledge, or are you looking for a leader, or are you looking for a comfortable hole to live in? What are you looking for?

I will restate my case. The Einstein equation of relativity is incorrect, for the Schwarzschild solution which it predicts is just an approximation of the true solution for that case.

Do you want evidence? How hard are you prepared to work to gain knowledge? Are you prepared to give away everything that you hold dear, and devote your entire life to the pursuit of knowledge? To be subject to mockery and scorn from all? To give up all instincts of animal survival? To be consumed like a piece of meat by hungry dogs? Until you are prepared to do that, then don't expect any precious knowledge to come your way.

Do you really expect that if someone arrives at a unified theory, that they are going to publish it for all to see? I suspect that no-one who is wise enough to develop a unified theory would be foolish enough to publish it openly, in the style of scientific tradition.

 

[matt grime]

It certainly appears that you don't understand what the word theory means. Tell you what, you put forward one single bit of evidence to support your case, and predictions of speeds faster than light aren't evidence of that (quantum entanglement amongst other things). It's all a theory, it will change, it will have to change if we are to get gravity into the quantum world. No one will have a problem with that in the slightest, and almost everyone would welcome that change.

 

[Stingray]

For those of you who tell me that the Einstein equation is right, why do you believe an equation that gives rise to singularities (at the Schwarzschild radius) and predicts motion faster than the speed of light? These would ordinarily be two very good reasons for discarding the equation., Yet several physicists have invested their entire career into its study.

Don't critisize what you don't understand. There are no speeds faster than light in GR, and there is no singularity at the Scwharzchild radius. There is one at r=0, but that is irrelevant to external observers. You could equivalently take the frozen star viewpoint.

Also, the Schwarzschild solution is not the only type of black hole.

You say that people shouldn't study GR in detail, yet there is no other way to understand them (or anything else in physics). Einstein's equations are written as G=8pi*T. Nobody would look at that the first time and think that it has anything to do with gravity. Yet if you work a little, you recover Newton's laws (as you must).

You can't do anything at all in any part of physics without analyzing the theory in detail. In the cases that it can be used (eg all of physics), math is a far more powerful tool for logical argument than natural language. When you do look at Einstein's equations in detail, there are many miraculous results that show up. Even besides the experimental evidence, there is a lot of theoretical evidence.

 

[Terry Giblin]

Black holes are fact what we think they are is fiction

Any theorem, can be always be improved including GR and QM, but as with the case of Newtons laws, they are the best we have at present.

However as with every good mathematical theorem, they both have their points of reflections or singularities.

We must remember, physics created the universe not mathematics, we cannot therefore always rely on mathematics for a precise solution, but it doesn’t mean we have to ignore the results from physics, until the maths catches up, or perhaps the M-Theory is closure than we image.

The size, mass, density, gravitation force, the amount of gravity waves of a black hole, is directly proportional to the amount of photons it can capture.

For every photon captured a graviton is released, in the form of a gravity wave.

Black Holes exist at the centre of every Galaxy and Quasars, the brightest and most powerful objects in the sky.

Yet we still perceive Black Holes is supper dark, dense, space and time warped.

We went looking for the darkest objects in the universe and discovered they were the most brightest and power energy emitters, exactly the reverse of what we had expected to find.

A point of reflection, instead of a singularity we find galaxies and quasars.

A Black Hole is a singularity in GR or QM, which can either be a ‘Black Hole’ large or small, such as in vacuum or quantum tunnelling, or eventual form into a Galaxy or Quasar. From ‘quarks’ to Quasars……

Whichever theory you believe, as long as you learn to accept black holes do exist, then, you have learned something very useful.


Terry Giblin

 

[Nereid]

*SNIP
Black Holes exist at the centre of every Galaxy and Quasars, the brightest and most powerful objects in the sky.

Yet we still perceive Black Holes is supper dark, dense, space and time warped.

We went looking for the darkest objects in the universe and discovered they were the most brightest and power energy emitters, exactly the reverse of what we had expected to find.

A point of reflection, instead of a singularity we find galaxies and quasars.

A Black Hole is a singularity in GR or QM, which can either be a ‘Black Hole’ large or small, such as in vacuum or quantum tunnelling, or eventual form into a Galaxy or Quasar. From ‘quarks’ to Quasars……

Whichever theory you believe, as long as you learn to accept black holes do exist, then, you have learned something very useful.

[nitpick]While there is good evidence for BHs at the heart of many galaxies and (all?) quasars, there are entire classes of galaxies for which there is no such evidence - irregulars, dwarf ellipticals/spheroidals, LSBs, ...[/nitpick]

What is observed in galactic nuclei is a 'spike' in the brightness; when this is examined with a spectroscope, unmistakable evidence of an accretion disk around a super-massive black hole is found.

This HST site has lots of PRs on observational evidence of black holes, both at the heart of galaxies and elsewhere. Note that there's plenty of other observational evidence of BHs, other than from the Hubble Space Telescope.

Jets, bright galactic nuclei, ... these are *exactly* what we expected to find, as evidence of BHs (not the reverse). Why? An active galactic nucleus is a SMBH in the process of 'feeding'; mass which is 'falling into' the SMBH does so through an accretion disk, which forms because the infalling matter has lots of angular momentum. The quiescent SMBHs - such as at the heart of our Milky Way - don't have accretion disks, and so you can't 'see' them. However, the existence of this SMBH has been confirmed by http://www.eso.org/outreach/gallery/vlt/images/Top20/Top20/press-rel/pr-17-02_pf.html