Scientists Find First Evidence That Black Holes Are the Source of Dark Energy (phys.org) 163
Observations of supermassive black holes at the centers of galaxies point to a likely source of dark energy -- the 'missing' 70% of the universe. Phys.Org reports: The measurements from ancient and dormant galaxies show black holes growing more than expected, aligning with a phenomenon predicted in Einstein's theory of gravity. The result potentially means nothing new has to be added to our picture of the universe to account for dark energy: black holes combined with Einstein's gravity are the source. The conclusion was reached by a team of 17 researchers in nine countries, led by the University of Hawai'i and including Imperial College London and STFC RAL Space physicists. The work is published in two papers in the journals The Astrophysical Journal and The Astrophysical Journal Letters.
The conclusion was made by studying nine billion years of black hole evolution. [...] The researchers looked at a particular type of galaxy called giant elliptical galaxies, which evolved early in the universe and then became dormant. Dormant galaxies have finished forming stars, leaving little material for the black hole at their center to accrete, meaning any further growth cannot be explained by these normal astrophysical processes. Comparing observations of distant galaxies (when they were young) with local elliptical galaxies (which are old and dead) showed growth much larger than predicted by accretion or mergers: the black holes of today are 7-20 times larger than they were nine billion years ago.
Further measurements with related populations of galaxies at different points in the universe's evolution show good agreement between the size of the universe and the mass of the black holes. These show that the measured amount of dark energy in the universe can be accounted for by black hole vacuum energy. This is the first observational evidence that black holes actually contain vacuum energy and that they are 'coupled' to the expansion of the universe, increasing in mass as the universe expands -- a phenomenon called 'cosmological coupling.' If further observations confirm it, cosmological coupling will redefine our understanding of what a black hole is.
The conclusion was made by studying nine billion years of black hole evolution. [...] The researchers looked at a particular type of galaxy called giant elliptical galaxies, which evolved early in the universe and then became dormant. Dormant galaxies have finished forming stars, leaving little material for the black hole at their center to accrete, meaning any further growth cannot be explained by these normal astrophysical processes. Comparing observations of distant galaxies (when they were young) with local elliptical galaxies (which are old and dead) showed growth much larger than predicted by accretion or mergers: the black holes of today are 7-20 times larger than they were nine billion years ago.
Further measurements with related populations of galaxies at different points in the universe's evolution show good agreement between the size of the universe and the mass of the black holes. These show that the measured amount of dark energy in the universe can be accounted for by black hole vacuum energy. This is the first observational evidence that black holes actually contain vacuum energy and that they are 'coupled' to the expansion of the universe, increasing in mass as the universe expands -- a phenomenon called 'cosmological coupling.' If further observations confirm it, cosmological coupling will redefine our understanding of what a black hole is.
Not a singularity? (Score:5, Interesting)
They're saying that black holes are not singularities? This is based on observational data?
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I thought it meant taking away its binky.
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You are betraying your lack of scientific knowledge with this foul language.
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No it is de-binking them, see https://www.urbandictionary.co... [urbandictionary.com]
So unkilling somebody or removing a slap to the head...
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For "First evidence" read "new theory that hasnt been debunked yet"
I think you're going to find that these cycles of outrageous theories, followed by, as you put it, debunkings, is hurting the reputation of science in general. More and more people are going "It sounds like bullshit, it ends up being bullshit, so why I should I listen to these "authorities"?
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You're right, science should stick to simplistic explanations that don't change in order to preserve its appearance of infallible authority. Like religion.
Re:Not a singularity? (Score:5, Informative)
According to the second paper linked in the summary [iop.org], there are theoretical models of black holes that do not feature singularities. The solutions to Einstein's general relativity equations that feature singularities--like Schwarzchild (spherical, non-rotating) and Kerr (rotating) black holes--require space to be flat far away from them. This is incompatible with the universe we live in, which is expanding at an accelerating rate. From the second paper:
As for black hole models without singularities
The measurements described in the paper claim to show that black holes grow and gain mass due to the expansion of the universe without absorbing the mass of stars and gases around them. If this interpretation of their data is true, this may be enough to show that actual black holes do not have singularities.
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The measurements described in the paper claim to show that black holes grow and gain mass due to the expansion of the universe without absorbing the mass of stars and gases around them. If this interpretation of their data is true, this may be enough to show that actual black holes do not have singularities.
Oh god, I can feel it in my bones now. Happily learning about the universe in the late 70s as a kid, I was assured the universe was either going to fall back in on itself in a Big Crunch, expand up to a point but never get there, or expand for ever but always getting slower. Weren’t sure which, but it was one for sure. Then, years later, all of a sudden we find out it’s expanding at an ever increasing rate. Ok, hurt a little, but we have a better model and the universe will end in a big rip
Re: Not a singularity? (Score:2)
"Next we will find out that weâ(TM)re not going to freeze to death at all but will find it ever more difficult to evade rapidly expanding black holes in some kind of Big Gulp - as we freeze to death."
I'm staying away from the 7-11!
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On the bright side, once the black hole gets big enough, the tidal forces at the event horizon will be small enough to be harmless.
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On the bright side, once the black hole gets big enough, the tidal forces at the event horizon will be small enough to be harmless.
That’s how they lure you in, with the “mostly harmless” sign. It’s like a free candy sign on the van down by the river; I’m not sure what goes on in there but I am sure I don’t want to personally find out.
Re:Not a singularity? (Score:5, Insightful)
he was merely explaining the paper, you idiot.
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he was explaining a paper that provides "evidence" that fiction A is the source of fiction B. And to do that, he stated fiction C as fact. and I'm the idiot?
Black holes exist. Dark energy exists. Both have been demonstrated with decades of evidence. You claiming that both are fiction says, yes, you are the idiot.
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Dark energy exists
No, it is still theoretical. We have yet to detect dark matter or dark energy.
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No, it is still theoretical. We have yet to detect dark matter or dark energy.
Physicists [wikipedia.org] say [wikipedia.org] otherwise [youtube.com].
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No, it is still theoretical. We have yet to detect dark matter or dark energy.
Physicists [wikipedia.org] say [wikipedia.org] otherwise [youtube.com].
Physicists have said things like "Everything is Superstrings!' too. Prove it. Real proof. Not another theory that's supposedly the proof for an earlier theory
Part of the problem is, some of this stuff can't be proven with the limits of our technology, so we're stuck with one PhD's math "proving" something, while an equally respected PhD's math debunks it.
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Physicists have said things like "Everything is Superstrings!' too.
1) Please cite when physicists have said that. What they have said matter might be composed of strings. 2) The poster said there is "no evidence" when there is decades of evidence.
Part of the problem is, some of this stuff can't be proven with the limits of our technology
What part of "there is decades of evidence" is unclear to you?
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You're mixing up observations with theories. Dark energy is an experimental observation. It's a label for "whatever is causing the universe to behave the way we've observed it behaving." We don't know what that something is, but we know it must exist. Because we really have observed the universe behaving that way.
Superstrings are theoretical. They were proposed to explain certain observations. Maybe they're the correct explanation. Maybe they aren't. Maybe some different explanation is the correct o
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Technically you're both right. It has not been detected, neither one
Different evidence from different measurements support the existence both dark matter and dark energy. When he says we have yet to "detect" both dark matter and dark energy, that is a lie. In another post, he said there was "zero evidence". Again, that is a lie. He can say he disagrees with the evidence or he is not personally convinced but to say there is "no evidence" is denialism.
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What part of "removing the need" suggests observational data to you? To me the clear subtext of that sentence is that a side benefit is removing an inelegance from the mathematical model.
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IANAPhysicist, and don't even play one on television, so this may be laughable nonsense.
But AIUI, scientists subscribe to two notions:
1) Information cannot be destroyed, and
2) There's a limit to the amount of information that can fit into a finite volume.
[FWIW I think (1) is an assumption and (2) is based on a proof, though I don't have any idea what assumptions the proof is based on.]
At any rate, given those two facts/beliefs/assumptions, ISTM that as a star collapses toward a singularity it will eventuall
Re:Not a singularity? (Score:5, Interesting)
Everything in physics is based on a combination of observations, proofs, and wishful-thinking in some proportion. You can't separate out one part from another.
That information cannot be destroyed is implied by quantum theory. It's at the end of a long chain of reasoning that has LOTS of observational backup.
That there's a limit to the amount of information that can fit into a finite volume is based on assumptions about the minimum amount of energy required to represent a bit. (And a bunch of other stuff.) And another long chain of reasoning.
IF there's a singularity present, however, the math breaks down. (For that matter, I don't trust anything that requires re-normalization to handle an explosion of infinities. That seems, to me, a clear sign that SOMETHING is wrong, even if the answers match observations.)
Calling the way some pieces of the math are handled "inelegant" is being exceedingly generous. I'd prefer calling it "a hackish kludge" or some such. The ones that get adopted give the answers that match observations, but the reasoning seems unsound. And there are lots of places like that in the reasoning. The only justification is "it seems to work"...and that's because of evolution. (I.e. the theories of calculation that don't work get dropped.)
So avoiding the singularity at the center of the black holes would greatly improve the theory....IF it works out to match observations.
Singularities don't make sense anyway (Score:2)
Why?
1) If something has zero size whether that be physical size of wavelength then it essentially doesn't exist.
2) Time inside a black runs slower the closer you get to the centre so that from the external universes POV the singularity would take an infinite amount of time to form.
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If something has zero size...then it essentially doesn't exist.
ie is a non-sequitur. A black hole has at least the mass that it collapsed with and subsequently swallowed. It's size, in terms of mass, is not zero.
Also, no one says singularities have zero size. The Einsteinian maths breaks down, and thus cannot say anything about the size of the singularity.
Time inside a black runs slower
That's what the cop said.
the closer you get to the centre
No it doesn't. It's all about reference frames. Time runs just as fast closer to a black hole than further away. It just appears to be slower when viewed from further away.
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"Also, no one says singularities have zero size"
That is exactly how standard black hole theory describes them.
"It's all about reference frames"
The nearer you get to the centre the stronger gravity gets therefore the slower time runs. Go argue about that with Einstein if you disagree.
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That is exactly how standard black hole theory describes them.
No it doesn't. "Standard black hole theory" does NOT describe anything about the singularity. It's called a singularity because the maths BREAKS DOWN. You are confusing popular science books with science.
The nearer you get to the centre the stronger gravity gets therefore the slower time runs.
From the point of view of SOMEONE FURTHER AWAY.
A clock closer to gravity experiences time the same way relative to itself. It doesn't experience a slow down.
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If something has zero size whether that be physical size of wavelength then it essentially doesn't exist.
You do understand that the concept of a singularity is that mathematically the center of a black hole where all the mass exists has no volume. In reality, black holes occupy space and have a definite volume and mass. The concentration of mass however cannot be measured to have a volume. The event horizon exists to separate the area of space where the equations and known physics break down.
Time inside a black runs slower the closer you get to the centre so that from the external universes POV the singularity would take an infinite amount of time to form.
Unless time does not exist inside the singularity. From what physicists can tell, all concepts of space and time break d
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Black holes do not have to be singularities. They simply need to be massively dense with a small physical size that fits inside the event horizon, we have no observation of a black hole being a singularity or not, we simply model it as such and act as if the model defines actual physical reality. Whether that size is a singularity or a few 10's of km's in diameter, the model is exactly the same from outside the event horizon (the only think we can see/detect). And note at the center of a high densit
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They simply need to be massively dense with a small physical size that fits inside the event horizon
Only at first, or rather at low mass/energies. Black holes are like macroscopic quantum objects and the radius of where light can’t escape grows linearly with mass. So to form one you need to take the most explosive power possible and force it backwards in a such a tiny space that something like a proton is unbelievably huge, but at the largest mass observed (ton618) are about 380 times less dense than air at sea level and if one was the size of the universe the mass would be the same as the univers
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Almost nobody thinks black holes are singularities. If I understand correctly, this provides a possible mechanism that could halt the collapse.
Re: Not a singularity? (Score:2)
Re:Not a singularity? (Score:5, Insightful)
What a load of dingos' kidneys. Physicists have always treated black holes as places where Einstein's mathematics blew up. The singularity is a mathematical singularity. Gormless people like you misinterpreted that as physical singularity. As best as I can understand the paper's model, they found mathematical solutions that do not have a singularity. Most quantum theories of gravity have no mathematical singularity. The paper appears to be saying one needn't go to a quantum theory of gravity to understand black holes. And on the way, they claim one interpretation for dark energy.
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The singularity is a mathematical singularity.
Tell that to the Romulans
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I mean, we've directly observed light being bent by gravity at every opportunity, and measured the slight-but-as-predicted time & mass dilation between Earth's surface and the ISS speeding by at .000027c. Some details remain opaque to us sure, and there is definitely more to the story than we know but the broad strokes consistently match the universe around us better than anything else.
Re:Not a singularity? (Score:5, Informative)
This is their way of saying they've been wrong for 50 years without admitting any such thing.
While others of us have been saying that singularities simply do not exist in nature, and their magical black hole theory is flat out wrong.
You are confused. Singularities have always been interpreted as being a sign that the theory is incomplete in some way, not that singularities must exist. Some people - especially "popular science" and SF writers - have discussed the implications of real singularities but for most people the singularity has been as real as Alice in Wonderland.
Re:Not a singularity? (Score:5, Interesting)
You remain confused. Penrose was addressing the idea that under real conditions the singularity problem goes away, and block holes in general do too. He showed that even under realistic conditions GR still predicts both black holes and singularities. GR predicts - the model predicts.
Most people still believe that this means something is wrong with the model and one of the main drivers in the search for a quantum theory of gravity is that it is thought it would remove singularities from the mathematics.
Discussing what the standard model in a field predicts and where it seems to be wrong is generally regarded as the best way to move forward to new theories and experiments, I believe.
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And magical pink ponies gather for their satanic rituals.
I'd heard Hasbro was playing with a way to tie My Little Ponies into the metal scene. I may actually watch that iteration of the show.
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Robot Chicken had some real fun concepts. Smurfette the slut stands out to me.
They're the equivalent of off-shore accounts (Score:2)
Corrupt members of the Galactic Council, as well as crime syndicates, use them to securely and secretly store their wealth. I laugh, but if there are other civilizations that would deign to interact with us, they are probably pretty venal as well.
That would explain UFOs, they're merely scouting out where to place their casinos and resorts.
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Some alien species throw their worst criminals into black holes, trapping their souls there for trillions of years and causing them to miss Judgement Day. Even if they spend all that time repenting, by the time they show up at the Pearly Gates there won't be anyone on duty to receive them.
It only looks from the outside that they are trapped for eternity as time slows down (as observed by us). :P Or so the religious nuts keep insisting.
But to them in their reference frame it doesn't. They grow old and die at a normal rate to them.
God is omnipotent or magic and stuff, so he can exist at all the times anyway and still judge and collect those tasty souls regardless
Russian dolls (Score:2)
[black holes] increasing in mass as the universe expands
So does this lead to the possibility that black holes are actually hidden (from our view) universes? And therefore that our universe is also inside a greater universe's black hole.
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I've been assured that the universe cannot be the inside of a black hole, but I didn't understand (or at least can't remember understanding) the explanation of why.
(I've got a vague feeling that the words made sense, and the sentences seemed logical, but I didn't understand the entailment between the ideas.)
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Living up to your handle, I see.
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You can fit our entire solar system inside a beach-ball sized black hole. So you could if the solar system were inside a black hole and somehow still intact.
No you cannot. You can fit the mass of a solar system inside a black hole. Once you move anything inside a black hole it is no longer "intact" so they are not what they were before. There are no planets in a black hole; it is also doubtful there are atoms as we know as subatomic particles like electrons and protons will cease to exist.
Do you know what it's like inside a black hole? Because there are plenty of Nobel Prizes awaiting for you if you do.
1) You are the one making the claim that solar systems stay intact inside a black hole so you should prove that they exist as you say. 2) From what we know of neutron stars wh
Considering the lack of evidence ... (Score:2, Interesting)
Considering the lack of experimental evidence for WIMPS and MACHOs, and of the additional particles that would be needed for supersymetry etc.. I'm actually pretty OK with this idea - The standard model works so darn well for the areas we have, and predicted the Higgs very nicely - but was not really predicting more as far as I understand it...
The missing mass issue ... clearly something is making the gravity -... either that or we need a new, better theory of gravity that works as well as General Relativ
Re:Considering the lack of evidence ... (Score:5, Informative)
The research is describing a mechanism for dark energy, exclusively - something coupled with the accelerating expansion of the universe.
WIMPS, MACHOs, etc. are all proposed explanations for dark matter, which is causes gravitational effects (strange rotation rates of galaxies, additional gravitational lensing by clusters, etc.)) unexplained by the ordinary visible matter in the cosmos. This new research - black holes growing over time - is not a proposed explanation for dark matter phenomena.
At one level, it's easy to conflate dark matter and dark energy. The similarity in naming is...unfortunate. And they both seem to make up a lot of the universe. And we seem to be pretty "in the dark" about what both of them actually are. On the other hand, the headline, summary, and article all refer to dark energy, and say nothing about dark matter.
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The standard model works so darn well for the areas we have
If it works so well, why do we require so many fudges and exotic things to make the models work? The standard model has (I think) 53 degrees of freedom. A model like that can fit anything. And that's the problem with it, if it fits anything, it explains nothing. That's why so many scientists have an issue with it. Also, when we try to combine the standard model with any macro level observation, things fall apart quickly and we have to introduce fudges like dark energy to make the equations work. This
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If it works so well, why do we require so many fudges and exotic things to make the models work?,
And your model of how the universe works had zero fudges then? Please present it to scientists. They would love to hear how you have solved everything that thousands of them have been toiling away for decades.
Oy, now we gain mass because we are expanding. (Score:2)
What would the black hole be sucking in if not energy or mass? I love a good theory but at least make sense on a basic level here.
-That article about particle physics scientists chasing theories instead of chasing observations
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No. "Vacuum" just means "empty space". The most common usage in general life is as an abbreviation for a vacuum cleaner, but that would more accurately be called a pressure differential cleaner or a pump cleaner. It doesn't create an actual vacuum.
Vacuum energy is the energy which a vacuum has. In quantum mechanics "vacuum" also turns out to be a bit of a misnomer, because even apparently empty space is a hive of activity. As long
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The thing is, you can't really say that a virtual particle exists, because it's always "created" together with it's anti-particle, and the sum of their energies is zero, and also the sum of all their other quantum numbers. There's the special case where one particle interacts with something that lends it enough energy so that the PAIR becomes real, but that doesn't happen in a vacuum. At least not except near an event horizon. Normally they promptly re-absorb each other.
They're called "virtual" because t
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Technically, vacuum means "lowest possible energy state." So vacuum energy isn't quite the oxymoron it sounds.
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I was taking a more historical development perspective. The choice of the word "vacuum" to describe empty space predates QM and was originally adopted from a non-technical Latin word meaning "empty" or "unoccupied". When physicists realised that there's no such thing as classical vacuum they decided to give an old word a new technical meaning. I still defend it as a misnomer: it was incorrectly named in ignorance, but rather than change the name when its was found to be incorrect they chose to change the me
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Steady-State Universe? (Score:2, Insightful)
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If black holes are found to be creating dark energy (and dark mass?) as space expands, maybe we should reconsider Fred Hoyle's 'steady state universe' model. It always seemed to me that his steady-state theory had a certain sense of completeness that the simple Big Bang theory lacked.
How? Fred Hoyle's steady-state requires us to ignore facts that we know are not true. Namely steady-state requires the universe to be
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And I believe you might be wrong about the density. Certainly the universe is expanding, but the article suggests that, on a macro scale, black holes are filling the expanding space with new dark energy/matter. So the density *is* constant while space and matter are both increasing in proportion. Unless I have misunderstood what was written
And as for ageless, well we do
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It was the basic idea of a steady state universe that I was suggesting that we reconsider, not necessarily all of the details.
But the idea of steady-state requires these details to be true. For example, if a universe is steady state, it cannot be expanding at the same time, etc. If the universe is not expanding then CMB could not exist.
And I believe you might be wrong about the density. Certainly the universe is expanding, but the article suggests that, on a macro scale, black holes are filling the expanding space with new dark energy/matter. So the density *is* constant while space and matter are both increasing in proportion. Unless I have misunderstood what was written.
You are mistaken. The total amount of matter and energy is known. What is not known is the nature of the energy and matter. About 5% of the total energy and matter is dark energy and dark matter. The universe is expanding thus volume is increasing. The total amount of matter has not changed. Thus de
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This is a correlation, nothing more (Score:2)
i don't get it (Score:2)
As I understand it, they are claiming that the apparent observation that black holes are growing faster than current theory predicts is predicted by their new theory which puts vacuum energy in the black holes.
But I fail to see how vacuum energy in black holes makes the universe's expansion accelerate, which is the basis for assuming dark energy or nontrivial cosmological constant.
The life cycle of the universe is in pulses. (Score:2)
If you consider all of reality abstracted down to a wave function, what you're seeing is that when the black holes take over that way, that wave function reaches negative 100 and and that starts the explosion that we know as the big bang.
This repeats the cycle of universe construction, cooling, rest, formation, evolution, and eventually, destruction again. Just consider that entire cycle one simple iteration of this loop. Our reality and our entire species as humans will only exist for this one iteration
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Re:Hmm (Score:5, Funny)
> I too wish to live 9 billion years. What's their secret?
You too can live 9 billion years. Just eat enough to reach 10^32 pounds. Better reserve a seat at the McDonald's.
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Re: Hmm (Score:2)
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Maybe the secret of longevity is the 8-digit UID?
Really? Slashdot is up to 8 digits now?
(But it you subtract the sock puppets and dead accounts and renumber then it would probably be 4 or 5 digits, tops.)
Re: Hmm (Score:2)
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I too wish to live 9 billion years. Whatâ(TM)s their secret?
Don't use the body creme from GOOP
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This is not about dark matter, but about dark energy.. They are not the same, and dark matter has more proof behind it than dark energy does (we have concrete evidence of dark matter being more dense in some areas than others, so something there must be different, aka there must be some dark matter). Dark energy is just an energy pushing the universe apart. These articles are proposing a model that avoids the need for dark energy it seems.
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There has been a great deal of search for "dark matter", and an insistence that it must be some exotic, non-baryonic, "can't detect it" magical substance of extraordinary properties.
That's because despite all known tests, this matter does not have the properties of baryonic matter. That is now the fact of the matter.
Physicists did very much the same thing with the "luminerous aether" roughly 150 years ago, and chemists did it with "phlogiston". centuries ago.
And physics abandoned both concepts when evidence said neither existed. Decades of evidence says there is dark matter; that is a huge difference.
It's not necessary: the "dark matter" measured in our cosmological models is based on extrapolations of extrapolations of extrapolations to measure size, density, and gravitational effects across billions of light years, and the data is just not good enough to make these extraordinary and exotic conclusions.
Ummm. No. Decades of observational data says dark matter exists as reported by many scientists. This is not some physicist smoking weed pondering about cosmological models. As for "exotic" observations is 1) there is a lot of matte
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Galactic rotation curves and lensing have several problems with their underlying measurement. One is the extrapolation of counting of high entensity events like supernova to conclude the number of stars of different types in a galaxy. The margins of error in the original measurements are large, and in the conclusions are much larger. But it's very fun to use a calculator computer and extrapolate very precise and complex physical models to explain what is not very good data. I'm afraid it's similar to modern
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Dark matter and dark energy have no evidence for them.
Well, that is just a lie. The rest of your rambling is based on lies. Wikipedia and Google searches can easily debunk your lies do I am labeling you as a denier.
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Wikipedia and Google also provide many reports of completely popularized nonsense. May I point you to a wonderful example of "Look it up!" in a debate? Take a good look at the very, very painful demand of a young lady without evidence that her opponent "Look It Up!!!" at the Oxford Union.
https://www.youtube.com/watch?... [youtube.com]
As your fellow advocate of dark matter and dark energy demonstrated above, the "Bullet Cluster" galactic collission should not be taken as convincing evid
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Wikipedia and Google also provide many reports of completely popularized nonsense.
No my point is that evidence is everywhere. To say there is "no evidence" means he did ZERO research. ZERO.
As your fellow advocate of dark matter and dark energy demonstrated above, the "Bullet Cluster" galactic collission should not be taken as convincing evidence. Please, if you see something that is actually convincing, do point to it.
You mean besides ALL the other evidence? It seems you are cherry picking and practicing denialism. One piece is not strong; thus all other evidence is not strong. That's your absurd logic.
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You're asserting there is evidence. From Wikipedia: The "evidence" cited there is pretty clear that it's not evidence, it's hypotheses. To quote wikipedia's article.
Because no one has directly observed dark matter yet – assuming it exists – it must barely interact with ordinary baryonic matter and radiation except through gravity
The primary evidence for dark matter comes from calculations showing that many galaxies would behave quite diff
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You're asserting there is evidence. From Wikipedia: The "evidence" cited there is pretty clear that it's not evidence, it's hypotheses. To quote wikipedia's article.
1) There IS evidence. He is either lying saying it does not exist or he is ignorant that it exists. The evidence is not good enough for you; that's your bias. It seems is that nothing will ever be good enough for you.
Because no one has directly observed dark matter yet – assuming it exists – it must barely interact with ordinary baryonic matter and radiation except through gravity
By your logic, no one has directly observed nuclear fusion in the sun; therefore it must not be fusion. It must be fairy dust. By your logic, no one has directly observed how viruses infect cells; it must fairy dust. Your insistence on "direct observation" is denialism at best.
Stellar and galactic evolutionary models of galaxies billions of light years away, of uncertainly deduced size, distance, and mass
Well that is a li
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Both the data and the model have weaknesses. So people keep trying to come up with something that fits better or limits the possible theories more. It's really quite difficult, and I'm no expert in that area. The "dark" in both "dark energy" and "dark matter" is a short-hand for "WTF is going on here!!?", it's not a claim to understanding. If this theory works out, "dark energy" will stop being a thing. (I.e., the name will fall out of use, not the observational data will disappear. It just won't be "
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it's not a claim to understanding
Dark matter is 1) matter that has been detected and 2) does not have properties of baryonic matter. What is more to understand?
I'm still trying to understand why the entire universe cannot be the inside of a black hole. I've been assured that it can't be, but my understanding of why is either too weak, or for some reason it just doesn't stick.
You do understand that we can measure properties of black holes and while we cannot know what happens inside a black hole 1) they do not have the mass of "the entire universe" 2) they do not occupy the volume of "the entire universe" 3) we don't a few things about black holes != we know nothing
This is like saying to someone: I don't understand why the entire country of the US canno
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Sorry, but no. Gravitational effects have been detected. That's not quite the same thing. Matter is the most familiar thing that causes that. When I try to think of something else I come up blank. But that's not proof that matter is actually involved. Maybe gravity doesn't act quite the way we think. (There are reasons to doubt that explanation, but they fall short of convincing.) Or it might be something nobody has thought of yet.
Even that's not quite right. Effects have been detected that are int
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Sorry, but no. Gravitational effects have been detected. Matter is the most familiar thing that causes that. When I try to think of something else I come up blank.
According to you, matter is the only thing that causes gravitational effects. This matter does not have baryonic properties according to physicists. . . . thus dark matter. Do you see the linkage now?
Maybe gravity doesn't act quite the way we think. (There are reasons to doubt that explanation, but they fall short of convincing.) Or it might be something nobody has thought of yet.
Then prove gravity does not act the way we think it does. You cannot just throw out gravity because you do not like the implications of gravity. At the same time, you could say it is all unicorn fairy dust but that is not science. That is dreaming.
Even that's not quite right. Effects have been detected that are interpreted as gravitational effects, and nobody has come up with any other reasonable explanation. But remember pholigiston and epicycles. Extreme certainty isn't justified
Let me understand your point. There are gravitational effects t
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You appear to be very uncomfortable with uncertainty. Perhaps I'm just less uncomfortable with it. I'm willing to be uncertain about what's happening there.
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What I'm missing is how this contributes to dark energy.
I haven't read the paper, since I won't understand it anyway, but I too am not getting this detail.
The most I'm getting is that they're "coupled". Somehow. They don't say how, at least not in the reporting of the story. But just that the expansion rate attributed to dark energy is coupled to the growth of black holes. They correlate, but they don't say the cause, at least in the reporting I've read.
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It is Sabine Hossenfelder saying this, and many guys here don't seem to like hearing what she has to say, so make of it what you will.
She does admit she hasn't pored through every detail of the paper and is just "shooting from the hip".
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"Shooting from the hip" is fine for a Slashdot poster. For someone pretending to offer an authoritative interpretation, not so much so. (But the real reason I'm giving her a pass is that I don't like videos. I prefer books. Still, I feel my criticism is justified.)
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Well, I didn't follow the link. I never follow links I don't pretty much recognize. So you may be talking about someone different from who I thought you were.
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I watched an interview with one of the scientists involved (from a couple years ago). Dark energy appears not to dilute as volume increases. That means it doesn't behave like mass or regular energy. However, you can get the same effect if you have fairly evenly distributed mass concentrations that uniformly gain mass as volume increases. The problem is explaining why that happens.
Black holes are fairly evenly distributed, at the scale of the universe. If their growth is coupled to the growth of the universe
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they get bigger as the universe grows, even without absorbing any mass.
Er what? Black holes do not spontaneously grow. The gravitational effects of a black hole grow as they absorb more mass. There are some gaps in models that some black holes could not have been around long enough to have their current mass based on the proposed lifecycle of stars. One suggestion is that these black holes may have skipped being a star and went straight to black holes.
What I'm missing is how this contributes to dark energy. Black holes attract stuff with gravity. Dark energy repels stuff. How do you go from even bigger gravity wells to repelling everything?
No. That is not how dark energy works: It is not "anti-gravity". The universe is expanding faster than original models predicte