Does Matter absorb space time?

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warmingwarmingwarming
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Re: Does Matter absorb space time?

Postby warmingwarmingwarming » Tue Apr 25, 2017 11:41 pm

http://www.mnn.com/earth-matters/space/photos/10-incredible-images-of-black-holes/universal-mystery

You might say the accretion disk is eating matter, not the Black Hole, and that empty space lies between the disc and the hole. I suppose.

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Chris Peterson
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Re: Does Matter absorb space time?

Postby Chris Peterson » Wed Apr 26, 2017 12:06 am

warmingwarmingwarming wrote:
Chris Peterson wrote:What images of black holes have you seen?

Just ordinary run of the mill stuff here on APOD and elsewhere .. always the image shows a Black Hole eating matter. Can you provide an image of a Black Hole NOT eating matter?

You have never seen an image of a black hole, because no such image has ever been made. What you've seen are artistic renderings of what some people think a black hole with an accretion disk might look like. But the vast majority of black holes don't have accretion disks, and are not detectable by any means other than observing the orbits of nearby stars (that is, for example, how we observe the black hole at the center of our own galaxy) or transient gravitational lensing. On APOD and other astronomical sites you may encounter accurate numerical simulations of black holes, converted to images:

https://apod.nasa.gov/apod/ap160212.html
https://apod.nasa.gov/apod/ap141026.html
https://apod.nasa.gov/apod/ap130702.html
https://apod.nasa.gov/apod/ap130701.html
Chris

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Chris Peterson
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Re: Does Matter absorb space time?

Postby Chris Peterson » Wed Apr 26, 2017 12:08 am

warmingwarmingwarming wrote:http://www.mnn.com/earth-matters/space/photos/10-incredible-images-of-black-holes/universal-mystery

You might say the accretion disk is eating matter, not the Black Hole, and that empty space lies between the disc and the hole. I suppose.

No. Matter is present in the accretion disk, and disappears into the black hole where the disk meets the event horizon. No gap exists.
Chris

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warmingwarmingwarming
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Re: Does Matter absorb space time?

Postby warmingwarmingwarming » Wed Apr 26, 2017 1:28 am

Chris Peterson wrote:
warmingwarmingwarming wrote:http://www.mnn.com/earth-matters/space/photos/10-incredible-images-of-black-holes/universal-mystery

You might say the accretion disk is eating matter, not the Black Hole, and that empty space lies between the disc and the hole. I suppose.

No. Matter is present in the accretion disk, and disappears into the black hole where the disk meets the event horizon. No gap exists.


So, if a Black Hole is collapsed space time .. then the Black Hole must be always eating space time .. otherwise it cannot eat anything, that is, if it's a sealed unit.

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Re: Does Matter absorb space time?

Postby Markus Schwarz » Wed Apr 26, 2017 9:01 am

warmingwarmingwarming wrote:So, if a Black Hole is collapsed space time .. then the Black Hole must be always eating space time .. otherwise it cannot eat anything, that is, if it's a sealed unit.

A black hole is not collapsed spacetime. A black hole forms when matter, usually a star, collapses. When matter collapses its matter density increases (same amount of matter in less space). The matter density curves spacetime. For a black hole to form, the curvature must be large enough so that not even light can escape. Matter can still fall into the black hole, but not escape.

warmingwarmingwarming
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Re: Does Matter absorb space time?

Postby warmingwarmingwarming » Wed Apr 26, 2017 11:36 pm

Markus Schwarz wrote:
warmingwarmingwarming wrote:So, if a Black Hole is collapsed space time .. then the Black Hole must be always eating space time .. otherwise it cannot eat anything, that is, if it's a sealed unit.

A black hole is not collapsed spacetime. A black hole forms when matter, usually a star, collapses. When matter collapses its matter density increases (same amount of matter in less space). The matter density curves spacetime. For a black hole to form, the curvature must be large enough so that not even light can escape. Matter can still fall into the black hole, but not escape.


So matter falls into the BH but not the spacetime that is surrounding the matter?
I think I think, though I'm not sure if I all the thoughts I think I think, or if they come to me from .. goodness knows where. :)

Markus Schwarz
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Re: Does Matter absorb space time?

Postby Markus Schwarz » Sat Apr 29, 2017 4:20 pm

warmingwarmingwarming wrote:So matter falls into the BH but not the spacetime that is surrounding the matter?

Correct! Keep in mind that matter does not have to fall into the black hole. A star, or planet could orbit a black hole in the same way as the Earth orbits the Sun or the Moon orbits the Earth.

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Re: Does Matter absorb space time?

Postby warmingwarmingwarming » Mon May 01, 2017 10:40 pm

Markus Schwarz wrote:
warmingwarmingwarming wrote:So matter falls into the BH but not the spacetime that is surrounding the matter?

Correct! Keep in mind that matter does not have to fall into the black hole. A star, or planet could orbit a black hole in the same way as the Earth orbits the Sun or the Moon orbits the Earth.


Pretty picky black hole.
I think I think, though I'm not sure if I all the thoughts I think I think, or if they come to me from .. goodness knows where. :)


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