# The Black Hole in the Milky Way



## Rosemary (Nov 6, 2005)

*Chinese astronomers close in on black hole in Milky Way*

     These astronomers have had the best glimpse yet of a suspected black hole in very centre of our galaxy.  They estimate the black hole is 300 millions kilometers wide.  Previous estimates have put it as twice that size.

   Black holes are not holes, but objects so dense that not even light can escape their immense gravity, making them invisible.  

   However, astronomers can detect radio noise from superheated dust and gas and can monitor the speed of stars trapped in orbit around them.  

     Scientists say this was the best evidence yet of the black hole, about 26000 light years from earth. 


*As a non-scientific person I have learnt something new today!  I always pictured these black holes as unlit tunnels through the dust and gasses…  *


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## chrispenycate (Nov 6, 2005)

A black hole is dimensionless- and even the event horizon around a black hole would be difficult to measure accurately (to an order of magnitude) by radiation from the destruction of matter around it- remember that those radio waves were hard gammas before they were red shifted down in escaping. Their paths were almost certainly bent by the gravitational field, by an amount very difficult to calculate without more information than we can conveniently garner at this time, Personally I find a simple to double estimate within acceptable accuracy.

The best way to measure it would be to wait for a star the other side to pass behind it, wait for it to come out the other side, and you can calculate both the mass it had a quarter of a million years ago and the angle subtended (from which, knowing the distance calculate the size. Of course the traverse will take a few centuries, so it's best not to be in too much of a hurry.


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## Rosemary (Nov 6, 2005)

chrispenycate said:
			
		

> A black hole is dimensionless- and even the event horizon around a black hole would be difficult to measure accurately (to an order of magnitude) by radiation from the destruction of matter around it- remember that those radio waves were hard gammas before they were red shifted down in escaping. Their paths were almost certainly bent by the gravitational field, by an amount very difficult to calculate without more information than we can conveniently garner at this time, Personally I find a simple to double estimate within acceptable accuracy.
> 
> The best way to measure it would be to wait for a star the other side to pass behind it, wait for it to come out the other side, and you can calculate both the mass it had a quarter of a million years ago and the angle subtended (from which, knowing the distance calculate the size. Of course the traverse will take a few centuries, so it's best not to be in too much of a hurry.


Thank you for that information Chris.  Well I don't have much happening here at the moment, so I have all the time in the world to wait.


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## chrispenycate (Nov 7, 2005)

Rosemary said:
			
		

> Thank you for that information Chris.  Well I don't have much happening here at the moment, so I have all the time in the world to wait.


Sometimes it just doesn't pay to be impatient. I went down to the CERN (centre european de recherche nucleaire- it's just down the number nine bus route- the "one ring to rule them") and asked for some antimatter to fuel my starship- and he estimated eight hundred million years to delivery. I decided not to hang around and wait for it. After all, you can always do something else in the meantime.


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## Rosemary (Nov 7, 2005)

chrispenycate said:
			
		

> Sometimes it just doesn't pay to be impatient. I went down to the CERN (centre european de recherche nucleaire- it's just down the number nine bus route- the "one ring to rule them") and asked for some antimatter to fuel my starship- and he estimated eight hundred million years to delivery. I decided not to hang around and wait for it. After all, you can always do something else in the meantime.


Just think of how many books you could write or to read.  Eight hundred million years is an awful lot of books.  
Still, on your way to investigate this Black Hole in the Milky Way, you could always stop off at some of the space stations and local planets to sell them, once you had refueled your starship of course.


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## HieroGlyph (Dec 22, 2005)

I cant recall who first proposed that 'Event Horizon'. But it was fairly clear to me that there is a sphere around a black-hole: and anything near that surface is likely to be drawn underneath it... Dont ask me what happens, its a little beyond my ability to envision. And the black-hole cosmologists and the like have 'discovered' at the core of our galaxy is millions of Sun masses... Another theory that holds its ground in the light of (forgive the pun) what we observe and what physicists are able to model. Waifs beware: you pale to insignificance...


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## Milk (Jun 10, 2006)

I think its generally understood by astrophysicists that most galaxies have black holes in their centers, and I may be wrong in this assumption. But Im just looking at it logically. If the Milky Way didn't have a huge black hole in the center it would be an oddball special galaxy where matter doesnt obey the normal laws of physics, becuase it would be one in which all these stars and debri orbited nothing! If a galaxy is a bunch of debri in orbit around a massive center, which it appears to me that galaxies are, then how could the center of a galaxy, any galaxy, with that much stuff in it, not be a black hole? I dont think that much mass (and I dont mean oddball stuff like dark matter which isnt understood yet) can cram together that tightly and not be a black hole.


Also from what I understand of event horizons, and this might also be incorrect so bear with me. Outside of one, there are zero effects to you-- outside of one you are not spaghetti. Inside on one you become spaghetti. Your toes turn into spaghetti shapes strectching towards the center of the hole (then feet, and legs and etc) and it happens very quickly for you. Being within the event horizon this spaghetti-ication process takes fractions of a second, but for the people outside of the event it takes thousands of years. Time slows for the person inside during their transformation into pasta, on what I would guess would be an asymptodic curve towards zero time where time stops completely. 
This is only becuase things appear to happen this way.. Asymptotic (spelling?) curves towards a zero or pointed at an infinity seems to be where all the interesting things 'nearly' happen. 
Somewhere during this process of noodling, you become hawking radiation.
And thousands, millions(?), billions (?) of years will have taken place outside the black hole while you have become a pasta noodle..

Actually I dont know during which part in this process Stephen Hawking jumps out and says 'poof! you are now radiation, you've made me famous!'


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## j d worthington (Jun 11, 2006)

Chris -- on this, I've not kept up with new information for some time (bad dog, bad dog), so I'd like to hear from you (or anyone who does know) -- last I heard the evidence was that all _spiral_ galaxes circled black holes, but galaxies that have other formations (and there are other formations, as I understand it) they weren't indicated. Has this been updated (see, I'm _very _far behind on this!)

While this is fascinating stuff, I frequently feel like my mind is being put through a taffy-pulling contest....


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## Naryaló S dú (Jul 27, 2007)

We still don't know if what's turning and pulling the galaxy towards its senter is a super-massive blackhole or some other phenomena.  Apparently this is common due to the many other spiral galaxy's with similar centers we've seen.


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