Milky way

[copperstream]

is there a black hole in the centre of the milky way????

[DrP]

IIRC - It is thought that all galaxies, including our Milky Way have a super massive black hole at the centre.

[D H]

It is not just thought that the Milky Way has a supermassive black hole at its center. It has been indirectly observed via the motion of stars near the center of the Milky Way. The star S2 orbits the center of the Milky Way in highly elliptical orbit with eccentricity 0.87, a period of 15.2 years, and perifocus of 17.2 light hours. Only a supermassive black hole can have this high a mass in such an incredibly small region. Reference: http://www.eso.org/public/outreach/press-rel/pr-2002/pr-17-02.html.

[antimatter]

Is it the tangential movements of the stars that keeps the whole galaxy from getting pulled in? Or is it just a slow process?

[Dark matter]

Is it the tangential movements of the stars that keeps the whole galaxy from getting pulled in? Or is it just a slow process?

 

What do you mean when you are talking about a "slow process?"

[Martin]

is there a black hole in the centre of the milky way????

 

sure, it is about 2 million solar masses

 

stars have been observed coming in real close, whipping around and sailing out, by how close we know the radius is small

 

and orbiting it with such speed that one can estimate the mass

 

therefore because it is so small and so massive we conclude it is a black hole because we don't have any better physical model for such a dense attractor

 

also it makes bursts of Xray, like other black holes do, presumably as stuff falls in. just more confirming evidence

 

I think it was around 2004 2005 that I saw the report, it was from the ESO telescope in Chile (European Southern Observatory)

and they had PLOTTED THE POSITION OF STARS NEAR THE HOLE, over several months, and made an ANIMATED FILM

which was online and you get to watch the stars in speeded up time.

 

I think I posted the link to it here at SFN, so we might find it.

 

It was neat. You get to see the stars orbiting the hole, and speeding up as they come whizzing in and barely miss it and whip around and go sailing out.

 

My memory of the mass as around 2 million solar is not precise. But that would make the diameter of the thing about 8 million miles.

 

As if the sun had a radius of 4 million miles and extended out to us about 1/20 of the distance separating us

and made an angle of about 5 or 6 degrees in the sky (instead of just half a degree or so)

and earth would be tear-assing around in its orbit much much faster just to keep from falling in.

 

Some other galaxies have much larger black holes. Like a billion solar. Milky's is quite modest-size, at only a couple of million.

=================

 

I was just typing from memory. There's MORE, MUCH MORE if you google "black hole center Milky Way"

 

Look at this! Here is an ANIMATION clip of 13 stars orbiting

http://astro.uchicago.edu/cosmus/projects/UCLA_GCG/UCLA_GCG_2000.gif'>http://astro.uchicago.edu/cosmus/projects/UCLA_GCG/UCLA_GCG_2000.gif

Here is the background text on the animation

http://astro.uchicago.edu/cosmus/projects/UCLA_GCG/

 

Here is a 2002 astronomy picture of the day, of that region

http://apod.nasa.gov/apod/ap021018.html

 

also apparently further observation has suggested there might be more than one black hole in the central region! also some group says they have measured the spin of the black hole.

there are competing estimates of the mass

 

Hey! I found the computer ANIMATION I remember seeing back in 2004. I posted SFN about it in the Astronomy Links thread

http://www.scienceforums.net/forum/showthread.php?p=94886#post94886

 

Here it is. Let's see how it looks 4 years later.

http://www.mpe.mpg.de/ir/GC/images/movie2003.mpg

Hmmm. so so. the other animation may be better

Edited June 3, 2008 by Martin