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Black Holes Grow By Eating Quantum Foam
An anonymous reader writes "The discovery that even the most distant galaxies have supermassive black holes at their cores is a puzzle for astrophysicists. These objects must have formed relatively soon after the Big Bang. But if a galaxy is only a billion years old and contains a black hole that is a billion times more massive than the Sun, how did it get so big, so quickly? Now one cosmologist says he has the answer: black holes feed off the quantum foam that makes up the fabric of spacetime. This foam is 'nourishing' because it contains quantum black holes that can contribute to the black hole's growth. This idea leads to a prediction: that the supermassive black hole at the center of the Milky Way must also be growing in this way and at a rate that we should be able to measure. Just watch out for the burps."
I thought supermassive black holes grew by sucking superstars into them.
#DeleteChrome
we're gonna need a bigger ringworld!
Quantum foam leaving a ring around the cosmic tub?
This is a job for Doug Adams, not Larry Niven!
"Flyin' in just a sweet place,
Never been known to fail..."
all the way through the hole onto the next galaxy
I got to the chocolate box before you, that's why the hard ones have teeth marks.
CERN scientists suggested they might create miniature black holes whilst looking for the Higgs Boson particle. There was some concern of the hypothetical danger creation of such black holes might pose. Now are we positing the first black holes of the universe fed off just such Quantum foam stuff?
"If P, then Q; Q, therefore P" has always countered the initial pleasure I feel when something is said to be newly understood in this way. "If black holes eat quantum foam, then they'd be like what we see today; Q therefore P."
Is there something in this prediction that nails down the cause of what we with black holes today see better than this sort of reasoning?
What Stephen Hawking stated when he said, virtual Partical/Anti-particles pop into existence due to vacuum pressure of space, normally they recombine back into nothing but when they happen to emerge on either side of the event horizon they black hole eats one of them.
Why do people equate mass with size? Because they've met your mom.
How does this growth rate compare to hawking radiation? Seems like there is still more to explain here.
How you get so big eating food of this kind?
In the case of a black hole? Because the radius of the event horizon - which is one of the easiest definitions of the "size" of a black hole - grows monotonically with the mass. You can see it from Newtonian physics; if you look at the distance at which a "particle" travelling at the speed of light can't escape from a body with mass M you find it grows linearly with M. It turns out, rather coincidentally, that this coincides with the event horizon of a Schwarzschild hole, which is a black hole which is perfectly spherical (ie non-rotating), uncharged black hole.
(I went looking for a reference but I gave up quickly. Basically take Newton's gravitational law, F=GMm/r^2 for a large body of mass M and an orbiting (test) body of mass m. A particle of velocity c moving in a circular orbit is experiencing a radial force of F=mv^2/r=mc^2/r. (This is the centrifugal force, and to head of pedants, in the frame of the particle it is very much experienced even if in an inertial frame it is evidently fictional.) Equating these two you quickly find GM/r=c^2, or r=GM/c^2. This is the Schwarzschild radius.)
I will be glad when they figure out that this is all just one huge (multitrillion year) cycle. Everything will eventually get sucked into the various holes; the larger holes will over power the small holes and suck them in until there is nothing left but one hole that eventually sucks our concept of time in to it until there only exists an extremely small and massively dense blob that reaches critical mass... at which point there is another big "bang" setting the entire process in motion again. Redistributed and reseeded.
Just another day down for Him. If one steps back far enough, everything has a cycle.
Next time you have a thought? Let it go.
Fail, off by a factor of two for the classical answer.
And first link: http://en.wikipedia.org/wiki/Escape_velocity
If a black whole can grow by eating space time then how could Hawking radiation ever evaporate it? It simply puts the black whole back into the "it breaks entropy" bucket.
Actually, I feel a Stephen Baxter book coming. If only he would stop writing about dang mammoths.
Sorry for the OT.
With one difference though: Once you apply GTR equations, the r is twice the value you get from Newtonian calculations.
Doesn't work - the big bang is not an expansion into pre-existing spacetime. Further, it's very hard to find a way of forcing a black hole solution of GR (Schwarzschild would be the most plausible in this context) to suddenly turn into a cosmological ("Friedmann-Lemaitre-Robertson-Walker") solution of GR. What you *can* do is embed an FLRW solution inside a Schwarzschild and get a model indistinguishable from observation, but extraordinarily contrived, and indeed pointless. (Come to that I'm not fully convinced those models genuinely work because the Schwarzschild solution is static, but if you linked that with Wetterich's recent model where the "expansion" is actually a manifestation of the increasing mass of particles you could avoid that issue, too and, indeed, avoid having to embed an FLRW inside a Schwarzschild at all.)
But if you refine what you say a bit it's not very far from an idea Penrose proposed a while back but has, unfortunately, never published in detail, although he's put out some (admittedly extremely ill-advised -- Penrose is basically a genius, but knows little of either statistics or observation) papers claiming signatures on the microwave sky. Basically Penrose points out that eventually everything will evaporate to radiation one way or another: if we follow any extension to the standard model we at least open the possibility that fundamental particles can decay, and otherwise ultimately every path every particle will take will inevitably, over an infinite period of time, take it into a black hole. If there are eventually two electrons in the universe and nothing more but radiation, they will themselves inevitably collide, after an unimaginable period, with enough energy to form a black hole (remember in this scenario the electrons are constantly buffeted by radiation of ridiculously high power... even if most of the radiation is at wavelengths of, say 10m, there will be *some* photons at a vast energy and these will interact with the electrons... eventually... and accelerate them to speeds far in excess of those reached on Earth or, indeed, in the Sun). And black holes radiate. So everything becomes radiation. But for reasons that are rather technical, it is impossible within the framework of GR to distinguish between an infinite future bathed in radiation and an infinite *past* bathed in radiation, because time and length scales become rather arbitrary. Which means that through some process Penrose has never explicated - if that's a word - the ultimate future can wrap onto the ultimate past and suddenly there's a new Big Bang.
There are also other ways of getting cyclic models, which involve a bit more new physics (new scalar fields, or branes hanging near ours, etc.) but a bit less hand-waving. Indeed, there are many ways of getting cyclic universes. But Penrose's struck me as being nearest to your suggestion.
oh whatever, a factor of two compared to entirely the wrong answer... it gives some intuition, at least. feel free to log on and mod me overrated :)
Yes, true. But like I said to the other AC who made the same (totally valid - people with mod points might want to mod these people informative, btw, so those who ignore ACs might see it) point, it's close enough for government work and it's good intuition.
But yes, both of you are right, the Newtonian calculation isn't entirely right. I should have thought a bit more carefully about what I was saying.
So they will grow forever until the universe is one giant black hole?
(-1: Post disagrees with my already-settled worldview) is not a valid mod option.
Since the entropy of a black hole is proportional to the area of the event horizon, and this is a reflection of the information content of the black hole, is there an issue with the information situation? Does the quantum foam that spontaneously creates these micro black holes inside the event horizon represent information? Or is there an information quandary implicit in this proposal?
In astronomy, all that matters is being within a factor of 10. :P
I read TFA and all I got was this lousy cookie
Quantum foam? They can eat all they want. I tried that stuff once, it was awful.
You never really know how close to the edge you can go until you fall off.
So... what do you think of the quantum foam that makes up the fabric of spacetime? The scientificness of such a thing is astounding, yes?
Da derp dee derp da teedly derpee derpee dum. Rated PG-13.
Actually here they're specifically talking about mass since it's about the only property of black holes we can measure
I'm not up on the details of contemporary physics, but it occurs to me that since the universe is supposed to have been expanding since the big bang, the overall density has decreased during that time. Does space/time and the Quantum Foam also have a density that might affect the rate at which super massive black holes could gobble it? Could conditions in the early universe encourage black hole growth/consolidation more than the current space environment?
Black hole growth via this method may still occur today, and be measurable in our own and nearby galaxies, but the rate may be so slow that it is hidden by other factors, e.g.: consumption of local stars/gas clouds.
âoeAny society that would give up a little liberty to gain a little security will deserve neither and lose both.
Indeed, given that black holes famously have no hair, we can't find anything more than mass, angular momentum and charge.
And, as you say, right now we have very little chance of measuring the angular momentum or charge of a black hole, while the mass is relatively straightforward...
Can we stop presenting cutting edge theory as fact? It's growing tiresome.
Physics headlines of today are starting to sound like headlines from the 1950's.
Or a factor of 10^^100, in the case of our measurement of the background temperature of space. Amazing how confident we are, with Google-sized errors staring back at us.
The background temperature of space is 2.7K, measured to exquisite accuracy (http://en.wikipedia.org/wiki/Cosmic_Background_Explorer). You might be referring to the dark energy problem, which is pretty much ill-defined, meaning we don't actually have an explanation or, indeed, even an agreement on the size of the discrepancy (which is commonly quoted as 10^120 but is actually much nearer 10^60... not that that's good.) Although you're likely referring to the string landscape, where you can get something like 10^10^100 unique vacua, or more, or maybe a few more than that, or a few more again. Which while the dark energy problem is ill-defined at least it's related - via a few assumptions, to be fair - to observation. The string landscape is entirely theoretical and relies on you accepting both string theory and the arguments that lead to the landscape - and those are much more controversial than the simple statement that the standard cosmological model does not work without a surprisingly large quantity that acts more or less like a dark energy.
Being inside a factor of 10 in mathematics matters most as well, 10 Erdos that is.
Head off pedants
You're welcome ;)
One astrophysicist now claims Black Holes are made by Freaking Magic...
This comes after NuSTAR found Black Holes "wherever it looked" {my words}, ""We found the black holes serendipitously," explained David Alexander, "We were looking at known targets and spotted the black holes in the background of the images."" anywhere between 0.3 and 11.4 billion light-years from Earth. http://www.sciencedaily.com/releases/2013/09/130909154918.htm
NuSTAR http://www.nustar.caltech.edu/ and http://www.nasa.gov/mission_pages/nustar/main/index.html#.UjDw25I03n0
Now it's a race to explain this, and in the lead is Marco Spaans with mini black holes aka "Quantum uctuations in the form" that I would
tend to think would of made itself more pronounced than just adding substance to a Black Hole.
haha two whacking mistakes in a post that claimed it wanted to avoid pedants. i have to try harder in future...
Yes, but "off by a factor of two" is considered accurate for cosmology.
And did you exchange a walk on part in the war for a lead role in a cage? - Pink Floyd.
If black holes grow by the absorbing the quantum foam, then the universe is slowly gaining mass as new matter is spontaneously being generated but not getting a chance to vanish back to where it came from. This means that eventually the cosmic expansion will halt and be reversed. This universe could end not in heat death but a big crunch. We may have the final answer in the ultimate fate of the universe if this theory is correct.
Beware of Sales Reps bearing gifts.
The paper in question has specific predictions about what we should expect to see when we examine pulsars that are near black holes and moreover those predictions look like they should be testable with only slightly more advanced technology than we have now if we take the time to make the long-term observations necessary. That's the primary difference: testable, predictable results. In contrast, religion generally either fails at making novel predictions at all, or makes novel predictions generally about eschatological issues (that is end of the world) that always turn out to be wrong.
A wise man once said, "The mass of the ass is inversely proportional to the angle of the dangle."
Unless you're Sir Mix-A-Lot, then it's a dirty lie propagated by Cosmo.
Fitting CAPTCHA: "playboy"
What if the black hole swallowed a really really large amount of Rogaine? Would it still have no hair?
[Yes, I know what Thorne and Hawking meant by the original phrase. Deal with it]
General Relativity: Space-time tells matter where to go; Matter tells space-time what shape to be.
This quantum foam is going to go right to my Schwartzchild radius.
Does this metric make me look supermassive?
It doesn't sound like too crazy of an idea to me, that these apparently precocious supermassive black holes were just left over from an earlier universe. Suppose our Big Bang erupted into a preexisting space, and these awaiting black holes significantly accelerated the galaxy-making schedule this time around. Yes, this time around.
Instead of hyperinflation expanding faster than light in the first microseconds, perhaps our Bang opened into a pre-existing "cavity" of a few light-minutes across. Perhaps we burst out of a dimple in the wall of a larger space; an ancient, nearly-collapsed universe, breathing new life into it and restarting inflation. Expansion was at purely Einsteinian speeds (is there such a term?), but an illusion was created of superluminal motion.
I've also got a theory that the acceleration of inflation is less due to mysterious 'dark energy' than to our halo of "new" matter approaching a halo of really, really old cold matter and inactive black holes that exists beyond the Hubble radius. The Great Attractor may just be a lump that is a bit closer than the rest.
Or acceleration may be due to our 3-dimensional universe passing over and through higher-dimensional topologies that are invisible to us but for their gravity. We've begun to roll downhill, for reasons of absolutely no significance, and we'll just continue to do so until things level out. The higher-dimension topologies being invisible to us, we just have to take them as we get 'em, like unexpected waves.
Quant1: Hey, I think you got quantum foam on my little black holes...
Quant2: Whoa you got little black holes in my quantum foam...
Bazinga!
Quant3: Who? Where? Huh? WTF am I? Some sort of little edgy black hole quantum burp?
If Stephen Hawlkings perceives me, does that mean I only theoretically exist?
OMG! Quantum Foam, little and supersized white holes & black holes...
wait, does this mean there could be grey holes in that quantum foam?
And which way do tachyons really go? Is there Quantum Swiss Cheese?
Yes I was thinking of the 10^^120 number. Now we have narrowed it down to either 10^^120 or 10^^60 -- near enough from astrophysical work. Thanks for the correction :-).
It ate one Sun per year for a billion years. Next question?
Mostly random stuff.
Sort of like the ancient Tai Chi Yin-Yang symbol which has a tiny yang white dot in the center of the 'full' black yin part and a tiny black yin dot in the center o the 'full' yang part. Okay, so yes, maybe I did reread those Dancing Wu Li Masters books in the last little bit.
I thought you were describing a quantum Reese's Peanut Butter Cup, myself.
Crap, now I'm hungry.
Il n'y a pas de Planet B.
Soon
So we have:
* Dark Energy
* Dark Matter
* Dark Gravity
* Dark Foam
* Dark Holes
* Dark Profit!
"I didn't eat the cake, honey, a Dark Mouth ate it."
Table-ized A.I.
Science Confirms The Universe Has Rabies!
Table-ized A.I.
Agreed. Why do you think Max Planck said:
* A new scientific truth does not triumph by convincing its opponents and making them see the light, but rather because its opponents eventually die, and a new generation grows up that is familiar with it.
* Science progresses funeral by funeral.
Wait till Scientists discover White Holes in a few years ... its gonna be a field day for astrophysics. :-)
Which means that through some process Penrose has never explicated - if that's a word - the ultimate future can wrap onto the ultimate past and suddenly there's a new Big Bang.
(TIC)
So there is life after death, see ya all on the rebound.
What would one use to accelerate fast enough to get out of this time loop?
That number is called "googol", not "google".
Rethinking email
Works for NASA anyway...well...almost.
I'm way past being amused by self-serving charlatans writing books, doing the lecture circuit, etc (more to have prestigious personal careers than to actually serve science) while pushing exotic theories like "string theory" and "foam" etc with no actual SCIENCE to give them more credence than, say, my personal pet theory of giant intergalactic polka-dot psychic monkeys.
Then why did/do you continue to waste time with popsci stuff and PR junk, and instead actually read the research papers involved. No one is going to wake you up for something that is already out there.
religion generally [predict] ... (that is end of the world) that always turn out to be wrong.
But man the one time when they're right about the End of the World, they just NEVER let you hear the end of it.
Oh, wait....
The whole thing, top to bottom. Science has literally become science fiction.
Black holes? Not real.
Quantum foam? Not even close to real.
This whole article is a fairy tale told by people who are paid (too) good money to sit around fantasizing things that fit their math but can never be checked or verified. It doesn't matter to them that black holes are a result of faulty math because the image of a monstrous object which sucks in everything around it including space itself (a ridiculous notion) makes for a great story.
I know this comment will be shot down immediately because I skimmed the 100 posts and see that every single one is discussing this newest daydream without any doubt at all that it COULD be true.
And I won't bother to give citations, there are plenty of sites at a Google's reach that can tell you anything you want to know about the non-mainstream. You'll either believe them or not (probably not). Plus I don't run any of them myself but if I linked one it would guarantee someone would call me the owner of it. Not that I'm going to keep reading this thread anyway.
It's just, you know... everyone is wrong here and someone ought to at least say so.
you are monopolizing, so I ask you directly.
a black hole is so gravitationally strong that nothing can escape. not even light.
how then can gravity escape, considering that the highs has measurable mass, in the gev range?
above should read higgs, Firefox mobile sucksfor editing.
a particle that conveys the gravitational force does nit make sense if it us the weakest force, yet can escape itself when others cannot.
does this not sound like magic? and I presume that we do not yet know. but if you have some idea, I really am bothered by this. familiar with brief history of time concepts, but nit with the newer universe.
Nothing to worry about, even Einstein didn't get the first three trivial calculations right that he made by solving simple cases related to his General Theory of Relativity. For curious minded people, he got perihelion of mercury calculation wrong by a factor of 2.
In Physics we learn that energy/matter cannot be created or destroyed, just change form, and that the universe is a closed system where the total energy/matter is static.
Recently we have also learned that virtual particles are constantly appearing and then disappearing and the void of space is not really a void but a boiling soup of virtual particles. But since these particles disaappear instantly after they appear, the net result is that the universe's energy/matter quantity does not change.
However, the idea in this article claims the opposite: virtual particles, i.e. the quantum foam, does not disappear, but it is added instead to the energy/matter of the universe, thus making the universe an open system. Isn't that a violation of the known physics laws?
"you are monopolizing, so I ask you directly."
Yeah, sorry :(
"how then can gravity escape, considering that the highs has measurable mass, in the gev range?"
The Higgs doesn't carry gravity. The Higgs field imparts mass to fundamental particles (and the Higgs boson is the particle associated with that field, though the particle itself does nothing for mass), but that is a very different thing. Quantum field theorists will describe gravity by *gravitons*, which are also bosons but where the Higgs has spin 0 -- identical from every angle -- the graviton has spin 2. The Higgs has a high mass, while the graviton is massless. Unfortunately this is itself a semi-classical picture, since these quantum field theorists have to specify a background spacetime to propagate a graviton along... utterly defeating the point if you're trying to look at this type of effect. (A massless particle would travel on the same paths as light - so a graviton in this language would evidently be trapped behind the event horizon.)
Instead when you're talking about regions of high spacetime curvature you should drop the language of gravitons and work straight with the geometry. I know a lot of quantum field theorists would mock me for that point, but I think they're as wrong as they think I am. Our best theory/theories of gravity are geometric in origin; the effects of gravity are not caused by a force but rather by curvature in the space we're traveling through. We try and go in straight lines, just those lines are curved. In this language you don't have any questions about gravity "escaping" from a black hole since there is nothing carrying gravity; it's just curvature in spacetime. A gravitational *wave* is a different thing - a ripple in spacetime - and while you'll hear people loosely talking of black holes emitting them, those waves emanate from outside the horizon. No wave will come from inside.
If we fired a Higgs into the black hole, it wouldn't come out again. However, that wouldn't do the mass of any fundamental particles in the area (things like the electron, and the quarks - protons and neutrons are not fundamental and most of their mass comes from binding energies rather than interactions with the Higgs field) because the field itself is still permeating the space outside the black hole.
Hopefully that's cleared at least one or two things up and not made it worse.
But what about dark energy? Maybe if a black hole grows too large, it not only accumulates mass, but also dark energy, until the dark energy gets stronger than the mass and we get a phase of inflation inside the black hole, creating a new universe.
it's not - we know it's 13.8 billion years old.
Higgs is irrelevant in this context.
But gravity cannot escape anyway (nothing which happens inside the black hole can affect its gravity outside). All the gravity you see comes from the mass which has formed/fallen into the hole, before it passed the event horizon.
I'm not trolling. If time dilation of a blackhole was infinite, then how does the blackhole itself interact with the rest of space-time in general?
As many people have said, the main theory is there are constantly equal amounts of opposite virtual particles being created and destroyed in empty space. There was a theory that along the edge of a black hole, precisely at its event horizon, a pair could get split apart before it can annihilate itself. That always seemed dumb to me because to sit on the very edge of an event horizon, it implies the opposing particle entered the universe with energy to accelerate it to approximately the speed of light in exactly the correct direction to stall out and just sit there. The end result, allegedly, is antimatter sitting along the edge of a black hole. How all the leftover particles are 100% antimatter and 0% matter seems odd to me too but whatever. Then, when the black hole gets a tiny bit larger, it sucks up the antimatter which shrinks its mass back down after it reacts with some matter inside the singularity.
So, lots of holes in that theory. This is just a watered down version of that horribly incorrect theory and it's equally incorrect. Also their stated end result violates most laws of physics relating to energy and mass creation.
Penrose is an advocate of mind is quantum magic, because otherwise my mad math skills would be bound by the laws of logic" -theory. I suggest a certain amount of scepticism regarding any claim of his which isn't accompanied by mathematical proof, especially when said claims would be equally at home in a New Age religious text.
Forget magic. Any technology distinguishable from divine power is insufficiently advanced.
Quantum foam makes me roam.
So black holes are playing Katamari Damacy with the universe?
I think it is Mathturbation. Like string theory.
"Flyin' in just a sweet place,
Never been known to fail..."
In the way you mean it, it doesn't. The event horizon is just that - anything inside of it doesn't interact with anything outside of it. It's simply where the name comes from. A 4-dimensional point in spacetime was dubbed an "event", so two regions of spacetime which can't see each other -- at any point in spacetime -- were said to be separated by an "event horizon". So a blackhole doesn't interact with anything, basically by its very nature.
However, it *does* cause a big curvature in spacetime. The main point is that it's no different from a star. Look at the physical situation: you have a star, which is a body supported by a balance between the pressures generated at the centre by fusion, against gravitational collapse. After some transitions from hydrogen burning up to, say, carbon burning (the end point is different for various stars but the ultimate limit is that stars don't burn iron; you lose more energy than you gain trying that, so it doesn't support a star) the fuel at the centre is exhausted and the star collapses. If it is heavy enough, it simply doesn't stop collapsing.
Now consider the spacetime geometry around it, and idealise a bit. Then before the star starts collapsing we have a massive spherical distribution of matter. Excellent. That's described by a Schrwazschild metric -- *any* non-rotating, chargeless, spherical distribution of matter is described by a Schwarzschild metric. (It's known as Brikhoff's Theorem.) But that will be true as the matter begins to fall across the Schwarzschild radius, assuming the physical conditions are such that it does so rather than bouncing (which depends on a vast number of parameters, including how massive it was in the first place, how fast the outer envelopes are falling when they hit the burnt-out remnants of the core - too fast and they may shatter the core which causes a bounce and ultimately a supernova... except even that may or may not leave behind a remnant white dwarf heavy enough to collapse first to a neutron star and then to a black hole - or it may tear the core apart completely, or end up in one of the intermediate states etc.). There's no reason to assume that the external geometry changes just because something suffers spherical collapse, right? That was true in Newtonian gravity and it turns out it's true in GR too -- the gravity outside a spherical object is the same as if all that object was concentrated at a point in the centre. So a collapsing spherical shell doesn't change the geometry. THe problem here is that the collapsing shell will pass through the event horizon. Nothing dramatic happens here -- a key tenet of GR is that we can always locally (for a given definition of "local" and that may be extremely local indeed) see things as if they're on flat spacetime. For astrophysical black holes that "local" is actually rather large. A coordinate system known in GR is the Painleve-Gullstrand system, which looks a bit odd but describes Schwarzschild space exactly (outside the horizon). Unlike "usual" coordinates, in Painleve-Gullstrand coordinates absolutely nothing untoward happens at the horizon: to something falling through it it looks like normal spacetime. The point of this tedious diversion is that nothign happens to the infalling spherical matter of the star when it passes through its own event horizon.
That then means that a black hole can form perfectly happily; no interaction with the outside universe is needed (and indeed doesn't mean much). If you were stupid or homicidal enough to chuck a colleague in, from your point of view he would mvoe slower and slower and get fainter and fainter as he approached the horizon, and you would never see him reach it.
From his point of view (if we ignore the spaghettification that would actually rip him to bits in most astrophysical holes) there would be nothign strange; he would rapidly cross a horizon he couldn't even identify, and then a microsecond or so later would inevitably slam into a future singularity that he could no more avoid than we can avoid moving into the next minute of our lives.
I would certainly agree that we should take a position of extreme scepticism towards Penrose's claims that quantum gravity gives rise to consciousness.
My contention is that Penrose is one of the greatest general relativists of the mid-late 20th century, and has only been overlooked because Stephen Hawking is in a wheelchair. What I'd judge as Hawking's greatest successes - and they were very great - were in collaboration with Penrose (in the singularity theorems), in collaboration with Ellis (covariant fluid dynamics) or were formulated in that period and aided by conversations with people like Penrose and Ellis (such as Hawking radiation). I would class the three of them as amongst the greatest physicists of the later 20th century, along with people like Kip Thorne, John Wheeler and Stephen Weinberg.
Unfortunately Penrose has also made a lot of strong claims he can't prove, and other speculations that he can argue and seem to make sense when he argues them in person, but which ultimately are very unconvincing. The quantum gravity leads to consciousness thing is certainly one of those.
Please don't hold it against him: the man is an extraordinary physicist.
Same as you shouldn't hold the papers he's put out with Gurzadyan in the last couple of years against him. Penrose has never claimed to be an observational cosmologist, nor a statistician. I believe, though I've never met him to ask in person, that he went along with Gurzadyan's papers because he thought that this was potential evidence for his pre-big bang model of cosmology. Unfortunately the circles on the sky that they identified are very, very definitely *not significant*, no matter how they try and argue it against people who are genuine experts in the field (and much more than I; I'm a weird cross-breed between theorist and observer, and therefore nothing like as good at theory as Penrose and nothing like as good at observation or stats as the people who so easily and convincingly dismissed his papers with Gurzadyan).
Depends very much on your model of dark energy. I'll go a bit out on a limb and say that we don't have anything approaching a convincing model of dark energy right now, with the best we have being that a cosmological constant exists. We do understand the spacetime of a black hole embedded in a universe with a cosmological constant - it's known as Schwarzschild-de Sitter space - and while that doesn't say how a universe of black holes and a c.c. behaves it's pretty telling that nothing extraordinary happens. But it does rely on a couple of assumtions (well, many more than that, but two significant right now): firstly, that dark energy is a cosmological constant, and secondly that we can describe the interaction of black holes and dark energy through semi-classical analysis. That means that we can use a black hole solution from general relativity and (potentially) a quantum mechanical description of the cosmological constant: assuming the quantum nature of gravity has no effect. Possibly not true. Moreover, dark energy may not be a c.c., or not only a c.c., in which case frankly bets are off, including on how the dark energy would behave inside a black hole. (It's not even immediately obvious it would act as you'd expect a dark energy too. Interior solutions for black holes are very strange beasts.)
Typical Fucktard Scientists
"black holes famously have no hair"
Unless, of course, the firewalls problem is real, in which case, the no-hair theorem is probably wrong (consider the ER = EPR solution to firewalls, for isntance).
Given that there is an apparent incompatibility involving at least one of AdS/CFT, EFT, and no-drama [ Mathur, Giddings, Braunstein ] hairless solutions probably require giving up the first. :/
See Polchinksi and the mannnnnnnnny recent replies on this topic.
Or hey maybe here as a starting point (go figure, didn't know it existed until now): http://en.wikipedia.org/wiki/Firewall_(physics)