Black Holes

[BertiWooster]

How does this compare in size to the black hole that is thought to be prowling about , in the milky way ?

http://www.bbc.co.uk/...-environment-11765483



// Although the blast was observed to occur just 30 years ago, its light actually took 50 million years to arrive at Earth.//

So travelling 186000 miles per second , the light has taken 50 million years to reach the earth .

WOW - such is the vastness of space - eh ?

[NazNomad]

I have a theory that black holes are just 'astronomical pinhole cameras' and we're just a mirror image of the real Universe on the other side, lol ;-)

Seriously though, the vastness of Space is one of those awe-inspiring things that I spend way too much time thinking about. Clear, unpolluted skies here don't make it any easier, it just means I can see even more things to 'wonder' over.

Amazing how we're all a part of it, yet most people can't imagine further than the local supermarket.

[jake-the-peg]

Not quite sure what you mean by prowling about. Do you mean the super-massive one at the centre of the galaxy?

That one is about 4.1 million solar masses this one is about 5 solar masses - it's not a baby due to size though but due to it's age.

The supermassive blackholes at the centre of galaxies are quite different beasts.

It's quite difficult to detect a black hole for obvious reasons. Most are detected because they are part of a binary system and are sucking material in and generaing x-rays.

There must be a lot of black holes about that formed from massive singular stars - the only way to detect them would be by the tiny gravitational lensing effect that they will have.

There could be many quite close that we have no idea of

[boxtops]

Are you talking about the new one Naz, the Chandra discovery?

[mibn2cweus]

Based on the number of stars in our own Milky Way Galaxy of sufficient mass to collapse into a black hole, there are an estimated 100000000 black hole inhabiting our galaxy.

http://hubblesite.org...es/encyc_mod3_q7.html

Here is a list of likely candidates - http://en.wikipedia.o...i/List_of_black_holes

Of course, not all black holes or there location are accounted for. Let's hope none come up missing - http://public.web.cer...en/lhc/safety-en.html

[jake-the-peg]

I wouldn't worry too much

People get the wrong idea about black holes.

If the Sun were suddenly converted int a black hole of the same mass we wouldn't suddenly get sucked in - our orbit would be just the same.

We would need to put on an extra jumper though

[NazNomad]

"Are you talking about the new one Naz, the Chandra discovery?"

I was talking about the vastness of space ... was this directed at the OP?

[ChuckFickens]

"If it took 50 million years it would have been 50,000.000 light years away."

It is.

[jake-the-peg]

yup

http://www.nasa.gov/m...ia/photoH-10-299.html

That's relatively near. Not part of the clocal group of galaxies that includes the Andromeda Galaxy and the magellenic clouds but part of the Virgo Supercluster of which we are part.

http://en.wikipedia.o...ki/Virgo_Supercluster

I still dispute NASA's description of it as in our "cosmic neighbourhood" - maybe I'm just too parochial

[mibn2cweus]

Jake, "I wouldn't worry too much" . . . I suppose I better go ahead and get that credit card payment in the mail . . . just in case! ;o)

[BertiWooster]

Just as a matter of interest - how do cosmologists calculate the distance of a star , from the earth ?

Further , if as we are told , the universe is expanding , wouldn't the distance be constantly changing ?