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Edwin
2003-Nov-28, 08:32 AM
Is it a black hole at the centre of a galaxy that makes it spin and become a spiral galaxy? And do all galaxies have one.

Littlemews
2003-Nov-29, 01:49 AM
Sigh..that&#39;s my question >< and Yes there is a Black Hole in the middle of the Milky Way, but not all of them has one....

jkmccrann
2005-Nov-29, 03:00 PM
Sigh..that's my question >< and Yes there is a Black Hole in the middle of the Milky Way, but not all of them has one....

Do you know that for a fact? Has that been proved that not all galaxies contain such black holes?

Faultline
2005-Nov-30, 11:48 PM
I think we've seen SMBH's in places where we didn't expect. Like Andromeda. It was supposed to have a quiet core. Instead, it hides a monster.

Finding a galaxy core SMBH means getting redshift/blueshift data on a few stars near the galaxy's center. Redshift acts sort of like a doppler radar. It tells you if something is moving quickly away from you. Stars moving toward you will have a blueshifted spectrum. If you see stars in close proximity moving in a swirling pattern, you have evidence that there is a big massive object there. If its massive enough, as calculated by the acceleration of the identified moving matter, it couldn't be anything else.

Other than that, there's the chance that where we haven't seen SMBH's at the center of galaxies, conditions may be wrong for us to detect them. There may not be enough matter there to measure.

alainprice
2005-Dec-01, 12:45 AM
Let me re-phrase your question.

Does a black hole induce galazy formation, or does galaxy formation induce SMBH production? A chicken and egg scenario.

Faultline
2005-Dec-01, 07:15 AM
Galaxy formation is terribly complicated. From what I've seen, galaxies with larger masses at their cores rotate faster, even though the stars at the outer rim are well beyond any significant effects of gravity from the BH. This would suggest that the SMBH has something to do with the creation of the galaxy, not the other way around.

Kaptain K
2005-Dec-02, 06:34 PM
Let me re-phrase your question.

Does a black hole induce galazy formation, or does galaxy formation induce SMBH production? A chicken and egg scenario.
This question is on the very cutting edge of cosmological research. The best answer is "we don't know...yet!".

Titana
2005-Dec-09, 06:17 AM
Galaxy formation is terribly complicated. From what I've seen, galaxies with larger masses at their cores rotate faster, even though the stars at the outer rim are well beyond any significant effects of gravity from the BH. This would suggest that the SMBH has something to do with the creation of the galaxy, not the other way around.



I always wondered why they say that the stars in the outer rim are well beyond any significant effects of gravity (has that been proved?). I would imagine that with the kind of gravity effects that a BH produces it would effect even the outer limits of a galaxy.



Titana.

Faultline
2005-Dec-09, 06:20 AM
I always wondered why they say that the stars in the outer rim are well beyond any significant effects of gravity (has that been proved?). I would imagine that with the kind of gravity effects that a BH produces it would effect even the outer limits of a galaxy.



Titana.

There's never a distance at which gravity isn't felt, but there is a distance to where the effects of even the effects of a SMBH's gravity are lost among the millions of neighboring stellar bodies that are nearer.