Huge Black Holes on Collision Course
- Thread starter London Geezer
- Start date
K.I.L.E.R said:
Kyle, stick to the maths.
We're not in the middle... 
They're just saying that the 2 black holes are far enough to have the Milky Way in between, which means they're very far apart and the event isn't going to happen any time soon...
They're just saying that the 2 black holes are far enough to have the Milky Way in between, which means they're very far apart and the event isn't going to happen any time soon...Bouncing Zabaglione Bros.
Legend
Given that just about every galaxy has a supermassive black hole at it's centre (indeed, it seems to be necessary for galactic formation), these kind of collisions must happen every time a couple of galaxies collide. It's pretty much what the articles says, only we don't see it happen too often because it's a relatively short-lived event.
zidane1strife
Banned
Two sides of the same coin, they're intrinsically connected but not exactly the same thing. The principles involved negentropy and entropy.K.I.L.E.R said:Don't they destroy life on other planets?
Why does there need to be a violent and horrific process for galaxies to exist?
The universe commits genocide against itself to form new life.
Life = death?
Before moving in on this topic in full, I'd like to clear up something mentioned in the article:
And yes, we expect active galactic nuclei (black holes that are gobbling up matter) to make the galaxy too violent for life, but I don't think we know that for sure. Most of the energy is emitted perpendicular to the galaxy, and thus wouldn't be seen at all by somebody within the galaxy.
When our galaxy eventually does merge with Andromeda (hundreds of millions of years out still, I believe), the black holes should merge, and they should also become active for a while. I'm not really sure right now what would be more dangerous: the disturbed orbits of stars and increased star formation associated with a galactic merger, or the turning on of the black hole. Personally I hope that by that time, we will have populated the entire galaxy, so that somebody survives the process.
The above is correct, but you have to be a little careful in reading it (which I think may be leading to KILER's confusion). Some black holes come from the collapse of massive stars. Others come from mergers of other objects. At the center of every galaxy is a supermassive black hole that has come from many mergers over a long period of time. And yes, these mergers are rather violent. We refer to galaxies that have black holes that are currently gobbling up matter as quasars. These are galaxies that are billions of light years away, but so bright that they look like normal stars to us.
And yes, we expect active galactic nuclei (black holes that are gobbling up matter) to make the galaxy too violent for life, but I don't think we know that for sure. Most of the energy is emitted perpendicular to the galaxy, and thus wouldn't be seen at all by somebody within the galaxy.
When our galaxy eventually does merge with Andromeda (hundreds of millions of years out still, I believe), the black holes should merge, and they should also become active for a while. I'm not really sure right now what would be more dangerous: the disturbed orbits of stars and increased star formation associated with a galactic merger, or the turning on of the black hole. Personally I hope that by that time, we will have populated the entire galaxy, so that somebody survives the process.
Yes, when Andromeda passes through the Milky way next time in a short while (in galactic timescales, that means only a couple of million years from now), it is predicted that... <drumroll>... six stars will collide.
Everything else takes a little more time, say about a few hundred million to a billion years from now. RUN! PANIC!
Everything else takes a little more time, say about a few hundred million to a billion years from now. RUN! PANIC!
I don't believe there is absolute proof of supermassive blackholes being present in the centre of every galaxy.
Some astronomers I have seen on various TV documentaries are very unsure what it is that holds galaxies together in the first instance and what is keeping them together.
Something to do with dark matter?
Some astronomers I have seen on various TV documentaries are very unsure what it is that holds galaxies together in the first instance and what is keeping them together.
Something to do with dark matter?
Bouncing Zabaglione Bros.
Legend
They were unsure until they figured out it was supermassive black holes. They knew there was far more mass/gravity in a galaxy than they could account for by calculating the rotation speed of the galaxy. Galaxies should fly apart given the visible mass and the speed they rotate, but they don't because there is a lot more mass in there somewhere.Tahir2 said:
Then they found a supermassive black hole at the centre of a galaxy that was visible because it was feeding. The black hole made up the difference in the calculations, and then every galaxy they looked at matched up in the same way.
Look, they were even making documentaries about it years back .
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Well, I'd say we're about 99.9999% certain right now that there are supermassive black holes in the centers of galaxies.
But BZB, supermassive black holes do not much help with the rotational speed problem of galaxies. Dark matter is what is needed to fix that problem.
The primary pieces of evidence for supermassive black holes are:
1. Billion+ solar mass contained within a small radius at the galactic core. With currently-known physics, the only possible thing that could be there is a black hole (and it is hard to imagine a physics model where there wouldn't be a black hole there). This mass is measured by observing the paths of stars very near the nucleus of our own galaxy.
2. We predict the black hole at the center would be spinning, and when a spinning black hole absorbs matter, it expels jets parallel to the axis of rotation. We have detected such relativistic jets of matter coming from the nuclei of several galaxies.
But BZB, supermassive black holes do not much help with the rotational speed problem of galaxies. Dark matter is what is needed to fix that problem.
The primary pieces of evidence for supermassive black holes are:
1. Billion+ solar mass contained within a small radius at the galactic core. With currently-known physics, the only possible thing that could be there is a black hole (and it is hard to imagine a physics model where there wouldn't be a black hole there). This mass is measured by observing the paths of stars very near the nucleus of our own galaxy.
2. We predict the black hole at the center would be spinning, and when a spinning black hole absorbs matter, it expels jets parallel to the axis of rotation. We have detected such relativistic jets of matter coming from the nuclei of several galaxies.
Bouncing Zabaglione Bros.
Legend
Chalnoth said:
I knew you'd be along to correct us on the cosmology.
I also have a layman's jumping off point for recent "where's the dark energy/matter" theories, if anyone else wants to do more reading up.
