Astrophysicists find no 'hair' on black holes
quantamagazine.org
quantamagazine.org
As far as I know, there's a third property that black holes have - electric charge. Would a sufficiently strong electric charge between two black holes be detectable, whether they both have the same charge, or opposing charges?
I suppose based on the article, the effects would only take places once the black holes got within 40km of each other...
If you pump in enough charge that the electrical repulsion is stronger than the gravity attraction, you can then store them safely next to each other, for when you might need one.
So I would recommend moving your civilization to a Dyson sphere around the black hole before aiming your cluster of LHCs at it.
It may be a very useful thing if it turns out that we can make small ones.
At the risk of spoiling the mystery of a 50-year-old short story, this happens in the The Borderland of Sol by Larry Niven.
Maybe you can time it to evaporate on your enemy, but that's an incredibly precise timing, and your enemy will literally be able to see it coming and deflect it.
> In theory, there’s a third defining property: electric charge. But real, astrophysical black holes have negligible net charge.
The question of hairy black holes is intimately connected to the greatest puzzle in modern physics: How can general relativity be merged with quantum theory?
Consider the situation where an object crosses a black hole’s point of no return, called the event horizon. According to general relativity, all outsiders will see is how the swallowed object contributes to the two numbers that describe the black hole: how much mass the object adds, and how much faster or slower it makes the black hole rotate.
As far as I can understand, it totally unrelated to Quantum Mechanics.
If Hawking radiation is real, it might also expose information from inside the black hole, possibly solving the information paradox. In that sense, the inside of a black hole would still be “observable” from the outside in the QM sense. But since we don’t know how quantum gravity works, that is an open question.
Consider two cars driving on a highway at the same speed. If one of the cars decelerates, it appears to be moving backwards relative to the other car, while still continuing to move forward relative to the road. It’s similar for light and an observer falling towards the singularity. They both fall towards the singularity, but light being reflected backwards will fall a bit slower, thus appearing to move backwards relative to the observer, even though the light still moves forward toward the singularity.
The longer answer (if you want to get in to the extensive literature) is that your question seems to relate to the black hole information paradox https://en.wikipedia.org/wiki/Black_hole_information_paradox
Rotating black holes are pretty well modeled as a spinning ring: https://en.wikipedia.org/wiki/Ring_singularity
meanwhile with black holes you know there is something, but you can't measure
in both cases you don't get any information, but in QM it's only because you already know everything there is to know about the system
could it end up being fundamentally the same thing? I don't see why not, but for it to make sense you'd have to get a nobel prize for grand unification theory first
also, collapse is not real and can't hurt you anyway, see many-worlds
And then the classical notions like information or entropy are not really compatible with General Relativity. Richard Tolman almost 100 years ago proposed interesting extension to the classical thermodynamics that is compatible and can potentially explain apparent paradox of information loss, but it is not known if that extension matches reality.
The crucial difference is "from the point of view of the sender". The black hole information paradox is that the information is lost from any possible receiver (even any possible ensemble of receivers surrounding the black hole). It's not the same thing
Which again points out that the classical notion of information just does not work in a universe with multiple causally disconnected regions.
Information is lost beyond the event horizon. There is no such thing as "point of view of receivers inside that black hole", everything collapses into a single point or some dimensionless thing or whatever. That's why it is called a singularity.
And that's not why it's called a singularity. It is NOT a single point, nor dimensionless. It has a well-defined dimensional size, the Schwarzwald Radius.
It shows.
You confuse "dimension" with "magnitude", for starters.
Why be so extravagantly supercilious on the internet?
It's ironic because it seems you're not that familiar with general relativity, and confuse the entire region within the event horizon with the singularity.
Black holes have a causally connected region within the event horizon which is distinct from the singularity, so there can in fact be observers within the event horizon that are in communication with each other, and they can have a perspective, i.e. receive information. The simplest black hole model would be the Schwarzschild black hole (a static, spherically symmetric spacetime, which is empty apart from the central mass) with the Kruskal-Szekeres coordinates, which smoothly continue over the event horizon.
Here's a nice discussion by John Baez about what you might see as you cross the event horizon: https://johncarlosbaez.wordpress.com/2024/11/30/black-hole-p...
To some extent though, what really happens within the event horizon remains speculative, because we can't directly verify any of these predictions about what happens there without actually crossing the horizon ("What happens within the event horizon, stays within the event horizon"). We just make inferences based on the structure of our currently most predictive theory for gravitational phenomena outside event horizons (which is general relativity, ofc)
Can you point out where? I'm always open to learn.
Btw, I don't read Baez as I consider him trash.
Here:
> Information is lost beyond the event horizon. There is no such thing as "point of view of receivers inside that black hole", everything collapses into a single point or some dimensionless thing or whatever. That's why it is called a singularity.
I'd say you're missing out by not reading Baez. He's an extremely gifted thinker and communicator. He knows his stuff
Barber goes "You're kidding me, right?"
Barber goes, "You're kiddiinnngggg mmmmmmeeeeeeeeee, riiiiiiiiiiiiiiiiiiiiiiiiiiiiiii...."
A Tachyon walks into a bar.
Physical beings which cannot be distinguished from one another would have made their heads spin...
It's been ages since I've read about him in any depth but I remember something about him having an idea that because of the indefinite divisibility of length then the elementary particles would have to have a diameter smaller than any given length, i.e. be infinitesimal, so they had quite sophisticated speculations
Click bait used to mean things like "five reasons you always get sick - number three will SHOCK you" or "doctors hate this one weird trick!".
The title of this article isn't click bait at all. Black holes having hair or not is almost the technical expression, as evidenced by the "no hair" theorem. Physicists are quirky like that sometimes.
Asking for a friend...
It's not a recent thing. Check out quark names and their associated properties.