Posted on 08/16/2021 11:38:08 AM PDT by Red Badger
Black holes are great at sucking up matter. So great, in fact, that not even light can escape their grasp (hence the name).
But given their talent for consumption, why don't black holes just keep expanding and expanding and simply swallow the Universe? In 2018, one of the world's top physicists came up with a dazzling explanation.
Conveniently, the idea could also unite the two biggest theories in all of physics.
The researcher behind this explanation is none other than Stanford University physicist Leonard Susskind, also known as one of the fathers of string theory.
He gave his two cents on the paradox in a series of papers, which basically suggest that black holes expand by increasing in complexity inwardly – a feature we just don't see connected while watching from afar.
In other words, they expand in, not out.
Weirder still, this hypothesis might have a parallel in the expansion of our own Universe, which also seems to be growing in a counterintuitive way.
"I think it's a very, very interesting question whether the cosmological growth of space is connected to the growth of some kind of complexity," Susskind was quoted in The Atlantic.
"And whether the cosmic clock, the evolution of the Universe, is connected with the evolution of complexity. There, I don't know the answer."
Susskind might be speculating on the Universe's evolution, but his thoughts on why black holes grow in more than they do out is worth unpacking. Of course, by its very nature, this type of research is theoretical, and not easily verified or disproved through the process of peer review.
But there are some pretty cool idea in here worth unpacking. To do that, we need to go back to basics for a moment. So... hang tight.
Put simply, black holes are dense masses that distort space to the extent that even light (read: information) lacks the escape velocity required to make an exit.
The first solid theoretical underpinnings for such an object emerged naturally out of the mathematics behind Einstein's general relativity back in 1915. Since then, physical objects matching those predictions have been spotted, often hanging around the centers of galaxies.
A common analogy is to imagine the dimensions of space plus time as a smooth rubber sheet. Much as a heavy object dimples the rubber sheet, mass distorts the geometry of spacetime.
The properties of our Universe's rubber sheet means it can form a deep gravity funnel that stretches 'down' without stretching much further 'out'.
Most objects expand 'out' as you add material, not 'in'. So how do we even begin to picture this? Rubber sheets are useful analogies, but only up to a certain point.
To understand how matter behaves against this super stretchy backdrop, we need to look elsewhere. Luckily, physics has a second rule book on how the Universe works called quantum mechanics, which describes how particles and their forces interact.
The two rule books of general relativity and quantum mechanics don't always agree, though. Small things interpreted through the lens of general relativity don't make much sense. And big things like black holes produce gibberish when the rules of quantum mechanics are applied.
This means we're missing something important – something that would allow us to interpret general relativity's space-bending feature in terms of finite masses and force-mediating particles.
One contender is something called anti-de Sitter/conformal field theory correspondence, shortened to Ads/CFT. This is a 'string theory meets four-dimensional space' kind of idea, aiming to bring the best of both quantum mechanics and general relativity together.
Based on its framework, the quantum complexity of a black hole – the number of steps required to return it to a pre-black hole state – is reflected in its volume.
The same thinking is what lies behind another brain-breaking idea called the holographic principle. The exact details aren't for the faint-hearted, but remain freely available on arXiv if you want to get your mathematics fix for the day.
It might sound a bit like downloading movies onto your desktop only to find it's now 'bigger' on the inside. As ludicrous as it sounds, in the extreme environment of a black hole more computational power might indeed mean more internal volume. At least this is what Susskind's Ads/CFT modelling suggests.
String theory itself is one of those nice ideas begging for an empirical win, so we're still a long way from marrying quantum mechanics and general relativity.
Susskind's suggestion that quantum complexity is ultimately responsible for the volume of a black hole has physicists thinking through the repercussions. After all, black holes aren't like ordinary space, so we can't expect ordinary rules to apply.
But if anybody is worth listening to on the subject, it's probably this guy.
The lectures were originally made available on the preprint server arXiv, and in 2020 were published as a book.
A version of this article was first published in December 2018.
We’re on both sides of the Event Horizon as we speak. ;^)
Let’s say a star collapses on itself thus becoming a black hole. The object that results isn’t any more massive it’s just mire dense. So you might as well ask why this star (and by extension any star) doesn’t engulf everything around it. The answer seems to be that things are moving - fast - and typically away from other things. Also the distances involved are quite large (as a result of all that stuff already having expanded).
I was just explaining a trait of black holes to someone who isn’t even very scientific and it blew his mind.
E = mC^2, right?
Yeah, but he doesn’t really understand what that means. It means a tiny bit of mass converts to a crapload of energy. It also means energy and mass are never destroyed, just converted.
Well, the holographic principle says that even though mass isn’t really ‘preserved’ as mass, the INFORMATION that mass contained IS preserved, perhaps on the sides of the black hole.
So every single impression every molecule in the universe ever has... ever... those impressions are recorded and preserved like bumps on a vinyl record, to be played back by God in the future with His super-duper black hole tape player thingamajig. When the bible says we’ll be held accountable for every single stray word we utter, that evidence will come from these play-back molecules in God’s Recorder, the Black Hole.
This is not true... Matter otherwise know as constrained energy consumes spacetime. It is that simple. E=MC2 The constraining of energy causes an event at the planck scale, at the planck time at plank frequency, spacetime or eventspace is consumed and must be replaced. Gravity is not cause by the warping of spacetime but the consumption of it. For some reason our most brilliant minds can’t see the obvious... I could be wrong, and I didn’t stay at a holiday in last night...
Well, I’m on the live-cat Schroedinger side for the time being. I am rapidly headed for rhat Heisenberg uncertainty zone.
Fascinating, thx.
It’s often said that we might be living in a black hole. But we look around at our universe and it is expanding. How can the interior of a black hole expand when everything we know about a black hole says it is collapsing, or has collapsed, down to a single mathematical point??? But now maybe we know? If you are on the inside, it is “expanding in.” But if you are on the outside, it’s collapsing. In relativity and quantum mechanics, there are things just as strange or stranger. So I can live with it!
I never look in the direction of a black hole when I utter discouraging words.
Why Don’t Black Holes Swallow All of Space?
Because space is really really big and mostly empty of things to consume.
Is it possible that physical laws can change in extreme conditions? Like before a singularity or just after? Or in the “interior” of a black hole?
If so, we can never figure out what has, or what will, happen. LaPlaces’ demon matters.
You are always looking in the direction of a black hole.
Pretty heady ideas from a former plumber (who never got his Journeyman’s card).
That would go against Entropy!....................
... for some people.....................
“ That would go against Entropy!.”
Not true.
Entropy has a positive relationship to energy and by inference, complexity.
;^)
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