Nice work by Atacama and Kagoshima
Sounds like an excellent bit of science. Well done to both observers and theoreticians. That deserves a few cold ones.
Black holes aren’t shaped like donuts after all, and actually look like water fountains instead, according to new research. “Previous theoretical models set a priori assumptions of rigid donuts,” said Keiichi Wada, a theoretical physics professor at Kagoshima University, Japan. Scientists believed that as surrounding matter is …
"To be clear, the black hole itself is still extremely spherical."
No it isn't. The only kind of black hole that can be spherical is a perfectly isolated one with zero charge and zero angular momentum, and it's impossible for that to exist in the real world. It's been known that neither the singularity or event horizon in real black holes are actually spherical for quite a while.
It's also worth noting that this article is completely wrong. From the paper:
"which would explain the longstanding mystery of the physical origin of the AGN torus."
Note that "torus" is the technical term for "donut-shaped". The paper doesn't say anything about the accretion disk being fountain-shaped instead of donut-shaped, the fountain is the explanation for how the disk becomes donut-shaped. Without that, it wasn't understood why it would be a thick donut instead of the expected thin disk.
> can a singularity be correctly described as having a shape at all?
Correct, it can't.
But what is usually meant is the event horizon around the singularity. And that certainly can have a well defined shape (as noted above in the zero charge, zero angular momentum case it would be a sphere).
Incoming gas is labelled "molecular", outgoing fountain gas is labelled "atomic".
I can readily imagine that the maelstrom around a black hole is the absolute worst place to be, but are gas molecules already torn into atoms at that stage ? Or is that just another way of saying "plasma" ?
These science bods need to change the way they describe things like "cold molecules" - can't imagine anything getting dragged into a blackhole is remotely cold!
Not sure about the other bit, but wouldn't be surprised if they are split into their component parts way beyond atoms? Really can't imagine many gas molecules surviving getting too close and still intact.
So you are saying there interesting computational processes happening on the event horizon?
For an idea similar to gravastars implying actually torus-shaped black holes, see here:
Sat 1 Dec 12:07:30 CET 2018
All of those theories appear to be an attempt to do away with the singularity using dark energy as an excuse in order to remove the destruction of information that was supposed to happen in the singularity and is not compatible with the quantum rules of the Universe.
But that destruction has been recognized as wrong by Hawking himself, so these theories have no more object.
Plus, the Event Horizon Telescope has not led to new, Earth-shattering revelations about the Milky Way's central black hole, so it looks like it is indeed just a black hole.
Opinion to be revised if scientific news warrants.
This will sound like a silly nitpick, but I dislike the phrase "It turns out that..." - especially when used in science articles. A few years ago it "turned out that" black holes were doughnut shaped, now it "turns out" they're like a fountain. Both times, the phrase implies that now we've finally got it right, and the job is done. It's not done, science is never done, and it's extra definitely not done when studying something like black holes.
(Not to take anything away from the actual research discussed here, which is excellent and fascinating).
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