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Black holes are confusing!
mipegg 
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Posted 1/19/13

mhibicke wrote:

Mipegg is correct and gave a succinct, accurate explanation. A black hole having no volume despite being massive sounds like a non sequitur because most people are accustomed to thinking of space as static rather than warpable. In actually, space-time is warped by speed and gravity (which is really just a force that can create velocity).

Imagine a whirlpool created by draining a full bathtub. If you think of space-time like it is being drawn in towards a black hole like water is pulled toward the drain, then black holes seem a little less abstract. This visualization is not really accurate, but does give you an idea of how black holes warp space-time to the extent where they don't actually occupy it. Instead, space-time bends around a black hole similar to the way a whirlpool bends around the center of a drain.


Also, when you compare a black hole to a whirlpool, all of a sudden wormholes (tunnels through space-time) seem pretty reasonable.




Ofcourse I also did a bit of handwaving, the explanation of saying the gravitation tensor only becoming infinite in one place is not strictly true, if you have a rotational blackhole things become more tricky due to the quantisation of angular momentum and charge. It still doesnt give the blackhole any size it just presents some interpretation issues.

The one I have never managed to explain properly is how time is linked into space, I'd imagine that I could just show people the 2+1 dimensional diagram of a light cone and they would get it, also lets you screw with their concept of the present too...
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Posted 1/19/13

mipegg wrote:
Ofcourse I also did a bit of handwaving, the explanation of saying the gravitation tensor only becoming infinite in one place is not strictly true, if you have a rotational blackhole things become more tricky due to the quantisation of angular momentum and charge. It still doesnt give the blackhole any size it just presents some interpretation issues.

The one I have never managed to explain properly is how time is linked into space, I'd imagine that I could just show people the 2+1 dimensional diagram of a light cone and they would get it, also lets you screw with their concept of the present too...


Yeah, but that is too much for a CR forum, and most people won't believe space-time relativity until they can calculate it for themselves, and won't learn the math for it unless forced to take a physics class. You did a good job.
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38 / M / Where the heart is
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Posted 1/19/13
For the CR forum user. If you have Netflix look up a show called How the Universe works. They have one, one hour episode that explains blackholes in an entertaining way. They don't go into brain scrambling science, but it's fun and informative.
mipegg 
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22 / M / England
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Posted 1/19/13

NoBreyner wrote:

For the CR forum user. If you have Netflix look up a show called How the Universe works. They have one, one hour episode that explains blackholes in an entertaining way. They don't go into brain scrambling science, but it's fun and informative.


That or one of the many BBC horizon programs are often quite good, in terms of general cosmology there is also one by Joao Mageueijo called Joao Mageujio's big bang which is fairly interesting
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26 / M / NY
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Posted 2/6/13
Black holes can be big or small. Scientists think the smallest black holes are as small as just one atom. These black holes are very tiny but have the mass of a large mountain. Mass is the amount of matter, or "stuff," in an object.

Another kind of black hole is called "stellar." Its mass can be up to 20 times more than the mass of the sun. There may be many, many stellar mass black holes in Earth's galaxy. Earth's galaxy is called the Milky Way.


The largest black holes are called "supermassive." These black holes have masses that are more than 1 million suns together. Scientists have found proof that every large galaxy contains a supermassive black hole at its center. The supermassive black hole at the center of the Milky Way galaxy is called Sagittarius A. It has a mass equal to about 4 million suns and would fit inside a very large ball that could hold a few million Earths.

http://www.nasa.gov/audience/forstudents/k-4/stories/what-is-a-black-hole-k4.html

From the folks at NASA
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20 / M / Delaware
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Posted 2/6/13
Interesting...
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18 / M / Ctf_2fort
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Posted 2/6/13
If you want to learn more about black holes, you could look up Vsauce on youtube. He does various videos explaining different science concepts like the black hole.
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Posted 2/6/13

mipegg wrote:


mhibicke wrote:

Mipegg is correct and gave a succinct, accurate explanation. A black hole having no volume despite being massive sounds like a non sequitur because most people are accustomed to thinking of space as static rather than warpable. In actually, space-time is warped by speed and gravity (which is really just a force that can create velocity).

Imagine a whirlpool created by draining a full bathtub. If you think of space-time like it is being drawn in towards a black hole like water is pulled toward the drain, then black holes seem a little less abstract. This visualization is not really accurate, but does give you an idea of how black holes warp space-time to the extent where they don't actually occupy it. Instead, space-time bends around a black hole similar to the way a whirlpool bends around the center of a drain.


Also, when you compare a black hole to a whirlpool, all of a sudden wormholes (tunnels through space-time) seem pretty reasonable.




Ofcourse I also did a bit of handwaving, the explanation of saying the gravitation tensor only becoming infinite in one place is not strictly true, if you have a rotational blackhole things become more tricky due to the quantisation of angular momentum and charge. It still doesnt give the blackhole any size it just presents some interpretation issues.

The one I have never managed to explain properly is how time is linked into space, I'd imagine that I could just show people the 2+1 dimensional diagram of a light cone and they would get it, also lets you screw with their concept of the present too...


Mind: *Explodes*
Posted 2/7/13
That is something you should ask a scientist about.
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31 / M / So Cal
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Posted 2/7/13
I love how everyone on here thinks they're the end all of information, and that what they're spewing out are the absolute facts.
You can't prove anything about a black hole, you can only theorize. So stop trying to tell each other how wrong they are and how right you are.
You just look like jackasses.

As physics are as we know them at the moment;

Anything that consumes matter must have density, especially since you can neither create new matter or destroy existing matter.
Gravity condenses, extreme gravity condenses extremely.
Our physics at the moment say, black holes do have a physical construct, meaning it has mass(size).

Consider a loaf of bread. If you crush it, you can make it pretty small. However, if you crush it with something containing immense force, you can make it even smaller. Crush it with something containing the force of a galaxy and the ignorant would assume it was no more. It would still be there, just too small for us to detect.
The only way to detect a black hole is the effect of gravity. Gravity, in simple terms, being a heaviness or weight that pulls other objects towards it, in most cases taken into consideration for celestial bodies, as anything small has too insignificant of a gravitational field to affect objects viewable by the naked eye.

Just keep your minds open to new possibilities, because that's how new discoveries are made and physics as we know it is changed.
Posted 2/7/13 , edited 2/7/13
A super powerful gravity anomaly which crushes everything down to the size of a pinhead. As for them being space/time fabric anomalies, wormholes, or other phenomena, theoretical at best.
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M / ???????? ?? ?????
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Posted 2/7/13
Black Hole history month?
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32 / M
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Posted 2/7/13

LynnTerra wrote:

Black Hole history month?

I'll bet black hole history is warped.
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Posted 2/7/13

ahatestory wrote:


LynnTerra wrote:

Black Hole history month?

I'll bet black hole history is warped.


I'll bet it sucks too
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26 / M / Pennsylvania, US
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Posted 2/7/13 , edited 2/7/13


You are actually the one who "looks like a jackass" here. There is so much that is blatantly wrong about your attempted explanation (including even basic terminology) that I don't know where to start. It's perfectly fine to be skeptical when you're learning about a subject, but when you go saying that people who clearly know a lot more about the subject are spouting misinformation you really just seem arrogant and closed-minded.
Here's some confirmation from NASA if you need an official source saying that black holes have zero volume, and thus infinite density:
http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/010912a.html

There's even a link in there that can lead you to some more detailed information, if you're interested.
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