36B solar mass black hole at centre of the Cosmic Horseshoe gravitational lens

[dweinus]

Using the formula for black hole density, a black hole of this mass would have an average density about the same as the near-vacuum atmosphere of Mars(!)

https://physics.stackexchange.com/questions/26515/what-is-ex...

[tlogan]

And it would take 10 days from event horizon to the singularity.

[jiehong]

That calculation of density is nice, but since we don’t know what’s inside a black hole, it doesn’t mean anything.

Passing the event horizon doesn’t mean you’ve reached the potentially ultra dense singularity, but it does mean you won’t escape.

[pizzathyme]

Definitely a dumb question but I had read "a teaspoon of black hole is more dense than Mt Everest" or something like that.

The near-vacuum atmosphere of Mars seems very light...? What fundamental concept am I misunderstanding?

[ramraj07]

Which isn't surprising if you think about it. Imagine the whole nothingness of the solar system being filled with even that density of gas. That's a metric ton of gas.

[physix]

This reminds me of when I was a physics undergrad way back in the mid 80s. We used to spend nights drinking beer and hacking some simulations from the Computer Recreations section of Scientific American.

Once we wanted to simulate the dynamics of galaxies. I don'it think it was an SA article, but we did it the slow way by calculating the force on every star individually from each other star. It was excruciatingly slow and boring.

Then some time later, I don't recall where I picked that up, I updated the simulation to just model the force on each star coming from the galaxy's centre of mass.

I could simulate many more stars, have galaxies collide and see them spin off with their stars scattering around.

What struck me was that they looked like real galaxies we see out there.

I wasn't aware of the postulations made in the 60s/70s about there being supermassive black holes at the centre of galaxies, but to me, this simplified simulation was kind of like a smoking gun for that... from an 80286 IBM PC AT.

[ubercow13]

Even the largest SMBHs mass is a minute fraction of their host galaxies' total mass so it is not the case that everything is just orbiting the SMBH.

[sebastiennight]

If we're assuming that the galaxy is radially symmetrical, doesn't it immediately follow that the combined gravitational force on a given star is the same as if we applied the force from a combined mass at the center?

This wouldn't work for something like the Solar system with a very sparse distribution of mass, but at the galaxy level it seems right even without the presence of a black hole.

[readthenotes1]

Cosmic Horseshoe galaxy, with pics

https://en.m.wikipedia.org/wiki/Cosmic_Horseshoe

[tenthirtyam]

Interesting. Given that the horseshoe shape is due to gravitational lensing of one far off galaxy ~19 Gly away by another "only" 6 Gly away, wouldn't that mean that any motion of those galaxies, or our galaxy, would realign the lensing and alter the shape of the horseshoe?

So... how long before we see the shape change? How fast do galaxies move anyway?

[henearkr]

About 9000 times the mass of the supermassive black hole at the center of our galaxy (Sagittarius A*).

[BaseBaal]

Mind boggling. Wish they included images of the scale compared to our sun, solar system, galaxy etc to help me wrap my head around this beast.

[BSOhealth]

With all the lensing going on out there, is it possible for us to observe the light from our sun (and potentially our planet) billions of years ago?

A cool achievement would be, observe the moon/earth separation event(s)

[throwup238]

Theoretically yes but although this black hole is big enough to make that more realistic, the redirected light would be have lost so much energy we’d likely be unable to observe it. We’d need an orbital hypertelescope to even stand a chance. Even then we wouldn’t see the earth because it would be drowned out by the sun.

The bigger problem is all the dust and other stars in the way. I’m not aware of any black holes close enough that would have a direct path for the light to cross without being absorbed and scattered.

[chiffre01]

How big would the diameter of this be ? Something like 8 light days ?

[myrmidon]

Sounds about right. Wiki has a correctly scaled picture with the two biggest known black hole event horizons and the solar system:

https://en.wikipedia.org/wiki/TON_618

Event horizon radius would be about roughly 1000 times the distance between Earth/Sun.

[ethan_smith]

The Schwarzschild radius would be approximately 106 billion kilometers or about 7 light days (r = 2GM/c²).

[AnimalMuppet]

A bit off topic: Is there any theoretical upper limit on the mass of a black hole?

[MurkyLabs]

It doesn't seem like there's a limit to how big they can get just a limit to how quickly they can get bigger due to what's called the Eddington Limit which explains how matter falling into the black hole emits radiation and if enough radiation around the accretion disk builds up, it can overcome the pull of the black hole and push matter away, at least until enough matter is pushed away that the radiation levels fall back under the limit and matter starts falling in again.

[tromp]

https://en.wikipedia.org/wiki/List_of_most_massive_black_hol... shows the maximal theoretical limit as 270B solar masses.

[jameskilton]

Given things like https://en.wikipedia.org/wiki/TON_618 and https://en.wikipedia.org/wiki/Phoenix_Cluster#Supermassive_b..., probably not. Seems like you can just keep shoving mass into it.

[bell-cot]

Yes - but it's basically the same as the total mass of the universe.

EDIT: I believe the above could be incorrect - if the universe has too much electrical charge or angular momentum. (And some other cosmological properties, so you couldn't get around the charge & spin issues.)

Might there be a black hole astrophysicist in the house, to comment on this?

[radicalbyte]

There is this whole theory that the observable universe is inside a black hole.

[cft]

https://youtu.be/EGzvGgNmaiY?t=58s

[msk-lywenn]

With good quantization, I bet we can get it down to 8B and it will easily fit on consumer grade galaxy.

(Sorry, I had to, with all the AI flood, I really was about to skip this info after the first 3 characters)

[ghurtado]

Don't be sorry, that was pretty good

[freddier]

They very rare great HN joke.

[belter]

Researchers discovered the black hole has been consuming AI VC money, at the rate of $50M per day, and so finally explaining why it is gotten so big.

[p1esk]

With good quantization you can get 36GB down to 8GB. To get 36B down to 8B you need good pruning.

[ozim]

I had a bit of a pause trying to figure out if someone named a model „black hole” from that title.

Hype is strong.

[M4R5H4LL]

thanks for brightening the day :)

[dataflow]

So you're saying it might fit on the S26?

[positisop]

Glad you wrote it, the title took me down the same path for a few seconds :-D

[deafpolygon]

that's too good, haha

[AmericanOP]

But can you make it talk dirty to me