A Really Big Black Hole

[steve_bank]

Back to the drawing board on cosmology?

https://getpocket.com/explore/item/...hink-it-was-possible?utm_source=pocket-newtab

Scientists did not think it was possible for a stellar black hole, one that forms from a dying star, to be as large as the “monster” it discovered in our own galaxy.
“Black holes of such mass should not even exist in our Galaxy, according to most of the current models of stellar evolution,” Liu Jifeng, a professor at the National Astronomical Observatory of China, said in a news release from the Chinese Academy of Sciences. “… Now theorists will have to take up the challenge of explaining its formation.”

 

[Loren Pechtel]

Hardly new news.

 

[Harry Bosch]

I'm absolutely fascinated with black holes. I read almost every story about them that comes out, and still hardly understand them.

 

[T.G.G. Moogly]

Could not two stellar black holes have merged? Why is this possibility not on the table?

 

[Loren Pechtel]

Could not two stellar black holes have merged? Why is this possibility not on the table?

1 + 1 = 1,000,000??

Black hole mergers are hard because they're such small targets.

 

[fromderinside]

Wash dry repeat a few thousand times. There's been at least 13.8 billion years after all. There's lots of matter crunching going on for a long long time. its a matter of utmost gravity one might say.

- groan -

 

[Shadowy Man]

Could not two stellar black holes have merged? Why is this possibility not on the table?

1 + 1 = 1,000,000??

The OP article says 70 solar mass black hole not million.

Black hole mergers are hard because they're such small targets.

And yet the gravitational wave detectors detected some almost immediately upon going into operation.

For example: https://www.nature.com/articles/d41586-020-02524-w

 

[Elixir]

And this from just a few days ago:

For the first time, researchers have confirmed the detection of a collision between a black hole and a neutron star.

Astronomers were alerted to both events soon after they were detected in gravitational waves and subsequently searched the skies for associated flashes of light. None were found. This is not surprising due to the very large distance to these mergers, which means that any light coming from them, no matter what the wavelength, would be very dim and hard to detect with even the most powerful telescopes. Additionally, the mergers likely did not give off a light show in any case because their black holes were big enough that they swallowed the neutron stars whole.

Some think that the universe has not existed for enough time to form as many supermassive black holes as have been observed (inferred), unless there were some epic very early collisions as parts of the primordial gas cloud collapsed directly into black holes, some of which then collided with each other. The gravitational waves caused by such early collisions would still be theoretically observable, but too faint and at a frequency to which LIGO is blind.
I heard that there are plans to build a bigger gravitational wave observatory that should be able so pick it up, but the predicted frequency is so ridiculously low that it will take years of data accumulation to actually know that the direct effect of those ancient black hole collisions is being observed.

 

[Jimmy Higgins]

Wouldn't the easiest explanation be that it isn't from around here? I've learned that in astrophysics, the easiest answer is always​ the truth.

 

[bilby]

We know that the early universe contained much larger black holes than this one.

More than ten billion light years away (and therefore early on in the history of the universe) there are black holes of tens of billions of solar masses.

The odd one much smaller and rather closer shouldn't be such a huge surprise. I can see how current theory renders such objects uncommon, but not how it renders them impossible.

Though that probably represents a lack of understanding on my part, if actual astrophysicists are saying they're contrary to theoretical possibility.

 

[DBT]

We know that the early universe contained much larger black holes than this one.

More than ten billion light years away (and therefore early on in the history of the universe) there are black holes of tens of billions of solar masses.

The odd one much smaller and rather closer shouldn't be such a huge surprise. I can see how current theory renders such objects uncommon, but not how it renders them impossible.

Though that probably represents a lack of understanding on my part, if actual astrophysicists are saying they're contrary to theoretical possibility.

Shouldn't these early formed monsters still be around? I mean 10 billion years shouldn't be enough time to evaporate black holes of that size, Hawking radiation, etc?

 

[bilby]

We know that the early universe contained much larger black holes than this one.

More than ten billion light years away (and therefore early on in the history of the universe) there are black holes of tens of billions of solar masses.

The odd one much smaller and rather closer shouldn't be such a huge surprise. I can see how current theory renders such objects uncommon, but not how it renders them impossible.

Though that probably represents a lack of understanding on my part, if actual astrophysicists are saying they're contrary to theoretical possibility.

Shouldn't these early formed monsters still be around? I mean 10 billion years shouldn't be enough time to evaporate black holes of that size, Hawking radiation, etc?

Yes, they're still around; We call them and their huge accretion disks Quasars, and their evaporation rates are tiny - Hawking radiation rates are proportional to the curvature of the event horizon, which for very large black holes is close to zero. Very small black holes evaporate very quickly - so quickly that they would appear to explode.

 

[Jarhyn]

We know that the early universe contained much larger black holes than this one.

More than ten billion light years away (and therefore early on in the history of the universe) there are black holes of tens of billions of solar masses.

The odd one much smaller and rather closer shouldn't be such a huge surprise. I can see how current theory renders such objects uncommon, but not how it renders them impossible.

Though that probably represents a lack of understanding on my part, if actual astrophysicists are saying they're contrary to theoretical possibility.

Shouldn't these early formed monsters still be around? I mean 10 billion years shouldn't be enough time to evaporate black holes of that size, Hawking radiation, etc?

Yes, they're still around; We call them and their huge accretion disks Quasars, and their evaporation rates are tiny - Hawking radiation rates are proportional to the curvature of the event horizon, which for very large black holes is close to zero. Very small black holes evaporate very quickly - so quickly that they would appear to explode.

If I understand, it's more a matter of "how did this one come to be here, in this place" ya?

 

[Jimmy Higgins]

Yes, they're still around; We call them and their huge accretion disks Quasars, and their evaporation rates are tiny - Hawking radiation rates are proportional to the curvature of the event horizon, which for very large black holes is close to zero. Very small black holes evaporate very quickly - so quickly that they would appear to explode.

If I understand, it's more a matter of "how did this one come to be here, in this place" ya?

Yeah, it is where it is currently that is a cause for confusion as it is seems out of place. I blame Obama. Or otherwise, maybe it got snatch when the Milky Way and another galaxy got a bit close.

Or goddidit.

 

[skepticalbip]

Yes, they're still around; We call them and their huge accretion disks Quasars, and their evaporation rates are tiny - Hawking radiation rates are proportional to the curvature of the event horizon, which for very large black holes is close to zero. Very small black holes evaporate very quickly - so quickly that they would appear to explode.

If I understand, it's more a matter of "how did this one come to be here, in this place" ya?

Where should it be? If a black hole of that mass exists then it's gotta be somewhere, why not where it is?

Seems to me that it would be harder to explain why it would be all alone halfway between the Milky Way galaxy and the Andromeda galaxy.

Could it possibly have been at the core of one of the many dwarf galaxies that the Milky Way has absorbed over the billions of years of its existence?

There are a hell of a lot that we don't know about the universe. This seems to me to be just one of them.