Info 'bout black holes, and is there one in the center of the galaxy?

In summary, black holes are massive objects that have such strong gravitational pull that even light cannot escape from them. There is a supermassive black hole at the center of our galaxy, with an estimated mass of 2.5-3 million solar masses. Time-lapse images have been taken of stars orbiting around it, confirming its existence. Websites like Wikipedia and Einstein Online provide more information on black holes and their properties.
  • #1
The-BRA!N
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1. What are some specifics about black holes?

2. I've heard there's a supermassive one at the center of our galaxy--FACT or FICTION?

Relevant websites, articles, etc. highly welcome! (I'm really interested in cosmology, obviously.)
 
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  • #2
The-BRA!N said:
2. I've heard there's a supermassive one at the center of our galaxy--FACT or FICTION?
...

Fact. Time-lapse pictures have been taken of stars orbiting it over an interval of 10-15 years, maybe more.
Its available online as a movie. You see the stars come in close and whip around and sail out----some of them have elliptial orbits.
If I remember right the estimated mass of our galaxy's central black hole is around 2.5 million or 3 million solar masses.
So the mass of a couple of million stars.

You said you would like some facts about BHs. What have you been able to find out from Wikipedia?

Is there anything about BHs at the Einstein-online website? It's a good source. A public outreach website maintained by one of the world's top research institutes.

Give us some links to what you have been reading already, if you like, so we know where you are coming from and have stuff to comment on.

I have a link to Einstein-online in my sig.
 
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  • #3
The-BRA!N said:
2. I've heard there's a supermassive one at the center of our galaxy--FACT or FICTION?

According to this sci-am article, astronomers put the size of source of gravity, equivelent to ~3.7 million sol mass at the centre of our galaxy, within a diameter of 30 million km. If you work out what the Schwarzschild radius is of 3.7e6 sol mass then this puts it in the right ball park to be a black hole-

http://www.sciam.com/article.cfm?id=virtual-telescope-galactic-black-hole

another sci-am article-

http://www.sciam.com/article.cfm?id=milky-way-black-hole
 
  • #4
I highly recommend you high-tail it over to Wikipedia and read up. It has some interesting things, if you don't know much about BHs, and it's always a good read. 95% of stuff is cited, so it's completely true. While I haven't been there, Einstein Online sounds like a great website, too. Just need to time to dig in deep. :)
 

Related to Info 'bout black holes, and is there one in the center of the galaxy?

1. What is a black hole?

A black hole is a region in space where the gravitational pull is so strong that nothing, not even light, can escape from it. This happens when a massive star dies and its core collapses, creating a singularity with infinite density and zero volume.

2. How do we know black holes exist?

We know black holes exist through observations of their effects on surrounding matter and through the detection of gravitational waves, which are ripples in space-time caused by the merging of two black holes.

3. Can anything escape from a black hole?

No, once something crosses the event horizon of a black hole, it is trapped inside and cannot escape. However, some particles can escape through Hawking radiation, but this process is very slow and only occurs in very small black holes.

4. Is there a black hole in the center of our galaxy?

Yes, there is a supermassive black hole at the center of our galaxy called Sagittarius A*. It is estimated to have a mass of 4 million times that of our sun and is surrounded by a disk of gas and dust that is being pulled into it.

5. Can black holes be used for time travel?

There is currently no evidence to suggest that black holes can be used for time travel. The intense gravitational pull near a black hole would cause severe time dilation, but it is not possible to enter a black hole and come out in a different time or place.

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