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Perhaps Black Holes are not what we thought...

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#1 BillP

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Posted 02 October 2019 - 10:59 AM

Here's a new story and paper published.  It contends that black holes may not have a singularity at their heart as popularly believed, and instead they might be full of dark energy.  If so it explains some things.  As the authors said:

 

"If what we thought were black holes are actually objects without singularities, then the accelerated expansion of our universe is a natural consequence of Einstein's theory of general relativity," said Kevin Croker, an astrophysicist at the University of Hawaii at Mānoa.

 

New Article - https://www.livescie...-not-exist.html

 

Paper (highly technical) - https://iopscience.i...4357/ab32da/pdf


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#2 bobito

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Posted 02 October 2019 - 11:18 AM

I think, in this context, the terms "singularity" and "dark energy" are pretty much synonymous.  They both mean "we don't know".


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#3 Mike McShan

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Posted 02 October 2019 - 11:23 AM

Really interesting read... Thanks for posting, Bill

 

Clear skies,

Mike



#4 starbuckin

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Posted 02 October 2019 - 11:31 AM

Cool!

#5 pkrallis

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Posted 02 October 2019 - 11:56 AM

Great article.   And it gives credence to the fallacy of CONCENSUS of scientists



#6 Jim Davis

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Posted 02 October 2019 - 12:01 PM

The problem I see with this is that they are using the Friedmann's equations, which are a simplification of Einstein's equations and are only a good approximation at scales over 100 Mpc. To use them to scale down to the size of a black hole would be highly suspect. Now, exercises like this are good for identifying potential alternatives, like looking at a problem from a different perspective.


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#7 DaveC2042

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Posted 02 October 2019 - 05:41 PM

The problem I see with this is that they are using the Friedmann's equations, which are a simplification of Einstein's equations and are only a good approximation at scales over 100 Mpc. To use them to scale down to the size of a black hole would be highly suspect. Now, exercises like this are good for identifying potential alternatives, like looking at a problem from a different perspective.


Spot on. They are essentially claiming that an approximation is more accurate than an exact solution.

Also, physicists do not think there is a real singularity at the centre of a black hole.

The solution of the GR equations has a mathematical singularity there. All this means is that our understanding of physics is incomplete and breaks down at that point.
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#8 BillP

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Posted 02 October 2019 - 06:06 PM

Great article.   And it gives credence to the fallacy of CONCENSUS of scientists

 

IMO "consensus" never means "likely correct".  All it means is that most are similarly mistaken lol.gif  Not through any fault of their own except never learning the lesson of history that shows you can only know what you currently know and as time and progress moves on, most of the scientific conclusions of the past get set aside as new understanding prevails.  So basically humans need to realize that we are mostly wrong all the time as in the next century we will discover things that invalidates most of our past theories.  All the scientific method can achieve is: "looks correct today, will most likely will be incorrect tomorrow" as this is the hallmark of self correcting processes, only correct as long as we never get better informed.



#9 BillP

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Posted 02 October 2019 - 06:12 PM

All this means is that our understanding of physics is incomplete and breaks down at that point.

 

IMO the use of "breaks down" implies the wrong thing, like something outside of physics causes it to break.  I know most like to use this phrase probably because it is nicer than the reality of things.  More properly IMO the phrase would be that "our physics is incomplete" or "our physics is incorrect" in these circumstances.



#10 DaveC2042

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Posted 02 October 2019 - 06:31 PM

IMO the use of "breaks down" implies the wrong thing, like something outside of physics causes it to break. I know most like to use this phrase probably because it is nicer than the reality of things. More properly IMO the phrase would be that "our physics is incomplete" or "our physics is incorrect" in these circumstances.


Incomplete is a much more accurate description than incorrect.

Our current big theories (quantum mechanics, relativity and statistical mechanics) describe most of what we see incredibly accurately.

When the new thing eventually comes along (say a quantum theory of gravity), it will give the same results as our current theories where they have been shown to work. It has to, or it's wrong. It will only give different results for things we haven't tested yet, and situations where the current theories don't give the right answer. Which is a very narrow window.

And in most situations we will simply keep using the old theories, as they'll still work, and be mathematically simpler. Much like how engineers still mostly use Newtonian physics.

So describing our current theories as incorrect doesn't really make any sense.
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#11 EJN

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Posted 02 October 2019 - 08:04 PM

Incomplete is a much more accurate description than incorrect.

Our current big theories (quantum mechanics, relativity and statistical mechanics) describe most of what we see incredibly accurately.

When the new thing eventually comes along (say a quantum theory of gravity), it will give the same results as our current theories where they have been shown to work. It has to, or it's wrong. It will only give different results for things we haven't tested yet, and situations where the current theories don't give the right answer. Which is a very narrow window.

And in most situations we will simply keep using the old theories, as they'll still work, and be mathematically simpler. Much like how engineers still mostly use Newtonian physics.

So describing our current theories as incorrect doesn't really make any sense.

 

Yes, general relativity did not render Newtonian gravitation incorrect, but a merely the "weak field limit" of

a more comprehensive theory.

 

 

The problem I see with this is that they are using the Friedmann's equations...

 

The Kerr metric for rotating black holes would be more appropriate.



#12 BillP

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Posted 03 October 2019 - 09:08 PM

Incomplete is a much more accurate description than incorrect.

 

Granted.  That is the view today.  But it has a number of places where it doesn't work, i.e., incomplete, but I feel the better word would be deficient instead.  Question becomes when they figure out how to complete the deficient places, will that then yield a new deeper theory replacing the Standard Model?  Close is good, but obviously not good enough.  As we are able to observe more or more deeply, likely it will pass by the wayside in time (even if a few hundred years).  But it works with the limitations of observation and understanding we have now.


Edited by BillP, 03 October 2019 - 09:11 PM.


#13 sg6

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Posted 04 October 2019 - 08:59 AM

I have a half suspicision that singularity is used as if the size is 0 then the maths falls out easier.

In my finals it dawned on me how one of the solid state equations worked.

Basically they said A+B = A, then simplified A.

Reason was that B was much smaller then A so could be discarded in effect.

 

Was able to add the key phrase:

As B << A then we can approximate with reasonale assuracy that Whatever = A.

And this simplifies to (whatever it was).

 

Has always made me suspect that what is at the bottom of a black hole is considered to be 0 as the maths is simplified. Also it sounds good.

 

If some evil function is dependant on the size then a size of 0 is "useful".

 

Will throw in why does it have to be gravity that makes a black hole black, relativity says "gravity" is an effect of the curvature of spacetime and not as such a force. Without a force then why is a black hole black ?



#14 EJN

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Posted 04 October 2019 - 11:46 AM

Will throw in why does it have to be gravity that makes a black hole black, relativity says "gravity" is an effect of the curvature of spacetime and not as such a force. Without a force then why is a black hole black ?


Inside the event horizon, all null geodesics (light paths) can only remain inside the event horizon, and all null geodesics terminate at the singularity, entirely due to spacetime curvature.

Edited by EJN, 04 October 2019 - 11:48 AM.


#15 bobito

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Posted 04 October 2019 - 12:37 PM

I have a half suspicision that singularity is used as if the size is 0 then the maths falls out easier.

...

My understanding is that the singularity represents infinity in the math.  Infinitely small, hot, and dense.



#16 Jim Davis

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Posted 04 October 2019 - 01:46 PM

My understanding is that the singularity represents infinity in the math.  Infinitely small, hot, and dense.

That may be an issue in our understanding, we don't have a mathematical theory to describe what is happening. Math is often developed when the need arises. The Greeks, using their geometry based mathematics, figured out that the square root of two wasn't rational. They were very upset about this idea, since they thought they had enough math to understand the world. Issac Newton ran into this, too. He had to invent calculus to explain gravity. Someone soon may invent the math necessary to describe the physics involve with black holes.



#17 DaveC2042

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Posted 04 October 2019 - 07:18 PM

That may be an issue in our understanding, we don't have a mathematical theory to describe what is happening. Math is often developed when the need arises. The Greeks, using their geometry based mathematics, figured out that the square root of two wasn't rational. They were very upset about this idea, since they thought they had enough math to understand the world. Issac Newton ran into this, too. He had to invent calculus to explain gravity. Someone soon may invent the math necessary to describe the physics involve with black holes.


I don't think the maths is the problem.

The fact that the maths blows up at the centre of a black hole simply means that our physics doesn't work there. The solution will be some new physics.

That new physics may then have some new maths with it, of course.


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