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Previously, we discussed the black holes in some topics like "Universe" "Speed of Light" and "Wormholes". I thought I would start a new topic on this subject.

So please contribute your view.

My understanding of the black hole is that it is a dead star that ran out of fuel. Instead of exploding to bits and pieces like in a supernova, the star collapsed upon itself upon it gravitational forces. The star become denser and denser, crushing everything. The force is so great that any object like other stars or planets will get pull into the dead star. Even light can't escape the gravitational pull. The black hole is something like a maelstorm or whirlpool at sea.

The general theory is that time are different when something fall into the black hole. I can understand why any object would get pull in by gravity, but I don't fully understand why time seemed to have stop.

Can someone explain this better?

Detecting a black hole is extremely difficult. Have they found a way yet to detect and find one?

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 storyteller


Actually black whole is a result of extreme supernova. I'm not too good in details but somehow the supernova eplosion (which is caused by the star collapsing) throws out the outer layers of star (the actual supernova) and simultaneously pushes the inside of the star into very tight package which can become neutron star or black hole depending on the power of the explosion.



Some of the Einstein's stranger theories say that gravity affects time and extreme gravity of black hole could therefore do extreme things like stopping time, maybe. A probe was sent some weeks ago to find out if gravity really does something to time. Until it sends data, it's all theories.



Many black holes have been found, in fact it seems to be very common for galaxies to be build around one.
Milky way revolves around central black hole. I think nowadays galaxies without central black hole are seen as the weird ones... Other black holes have been found too (other than central ones) and there seem to be many kinds, some seem to be reluctant to suck in material and that's been confusing scientists recently. They are called "lazy" blackholes. Now wormholes have been found, though somebody (Einstein?) said that if black holes exist, wormholes certainly exist as well (somehow same theory explains both). I think first black hole was found in the 70's so they both were science fiction until then. Maybe wormholes are harder to see until you accidentally go through one :-o

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 Crypdoctor


This probably explains why that the majority of the galaxies we see are spiral or whirlpool-like in shape.

I have never heard of "lazy" blackholes before. Gee, these astronomers often given strange name.

I didn't know that they have prove or found "wormholes" yet.

I have heard that black holes not only sucked everything in, but they also spit out something (I don't remember what) from its two poles. So something does escape from the black hole. Do you recall what they spit out?

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 storyteller


I'm not sure but I seem to remember that this "beam" doesn't in fact come from inside the black hole, instead some of the material spins so fast when going in that it gets thrown out somehow...Doesn't seem to make sense
Anyway, material doesn't go straight in the black hole, it goes into a spiral-like orbit that gets smaller and faster, and in this process the matter gets so hot that it radiates a lot and that's how black holes are "seen". That's one way at least...

I think I saw something about black holes that actually spit out material, explode or are somehow "full" and none of that make's much sense. Seems like the traditional black hole that is just being heavy and sucks in things is one of the simple types...

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Let take for example, two objects A and B.

Object A is outside of the black hole looking at Object B, which is being pulled in by the black hole.

Would Object A see -
a) Object B moving fast or slow?
b) or Object B would it stop moving?

And what would Object B see, looking at his surrounding and looking back Object A?

Would object B be stretched?

What would happen to a person within Object B? Would he be pulled apart? Or would he implode?

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I guess until the object be actually in the black hole it is just a regular fast-moving object. Not so different from anything else being pulled by strong gravity. When it gets into the black area, what happens then? I suppose no one knows.

I read somewhere that in case of a black hole density of matter is same as if the sun was same size as an apple :-o

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wow, that big?

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Of course in order to make a black hole you need to start with something lot bigger (and heavier) than sun and crunch it to ball about few kilometers in diameter... If I ever make a compression algorithm, I'll call it a black hole
or maybe not... on the second tought it doesn't look very selling name after all :-o I've got enough black holes on my computer already

Well anyway seriously speaking, a thing almost as dense as a black hole is a neutron star, and that consists of neutrons only (or so I've heard). No space between them (normally atoms are really far apart, relatively speaking), no electrons... and black hole is something denser. Hard to imagine what kind of stuff it could be... One single particle?

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hmm, good name for a one-way compression algorithm i suppose! though i can't think of a use for one-way compression . . .

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how many black holes have been found until now?

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I've heard recently that Steven Hawking has been contradicting his original theory about the Black Hole. He is now saying that some stuff that get suck into the BH, may one day (in a very distant future) spit out. I'd guess that scientist does sometime re-evaluate their theories as time go by.

Didn't Einstein regret one of his theories? I don't remember which one it was, though.

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hey if it is a BH is it hot or cold. it sucks all in it so it is cold and warm. and why can we see a BH if it sucks light in. is god able to stand in a BH. will anything evolve from a BH? if it was given enough time would it create another big bang. does black magic come from BH and is that why cant hve it yet. have we not evolved enough. and i am a swimmer so when will i have gills and fins and scales.

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You detect black holes from observing the objects around it. It's true most galaxies have black holes in the center, some 'feed' and others don't, this are inactive galaxies. This is observed by the rate of stars that 'orbit' the BH. Gravity can be determined and if great enough will conclude presence of black hole(s).

I think theirs a proximity that a black hole 'works' or feeds, and when that area is exhausted it becomes 'inactive.' but the gravity force is still their and objects orbit it.

[quote]
I'm not sure but I seem to remember that this "beam" doesn't in fact come from inside the black hole, instead some of the material spins so fast when going in that it gets thrown out somehow...Doesn't seem to make sense
[/quote]
true, thats all i can say... but thats how it happens, has to do with angular acceleration and force.

I don't think that things are possible of coming out in the same form, they were compressed beyond reorganizational limits... would like to see article if exists.

Time changes on the object because of the forces that act on it. The twins paradox for example. It has been concluded that this is in fact true, as a atomic clock sent one way around the world is off from a clock flying the other way. if you left the earth at the speed of light, and returned 5 'earth' years later, you'd aged a matter of days. theirfore in a BH, with extreme force, time is changed, and i believe, doesn't exist.

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The spitting out stuff is just in the movies. Black holes, which firstly are not holes are tiny and extremely dense objects. From what i have learned it is originated from a supernova which is an explosion of a star after it dies. The supernova falls under its own gravity to form an extremely dense object. This objxt is smaller than a full stop. This BH has a strong gravitational force and pulls in nearby objects. These objects are compressed as well and therefore they are thought to be disappeared.

As Einstein says gravity causes space time disortions. This is in addition to bending light. Time is considered to be the fourth dimension and therefore it is also 'affected" or distorted like mass, light and everything else.
If you live two years on Jupiter and come back to Earth you would find people older by less than what you lived there, because there is more gravity. Threfore, if you live on a black hole which will never happen, time will be hundreds of times faster. If you are on a blackhole and someone is waving to you. You will probably die before he finishes waving because time is passing fast where you are.

I feel like i'm making no sense.

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 Username Here writes...

No.

I am not sure if this has yet been proven or not. I don't always follow any science reports/articles as I would like too, but this is not just movie or fiction.

Like some galaxies, (eg. Milky Way or the Andromeda galaxy), and our solar system (the planets orbit around the sun), objects, energy and light will travel towards the BH on ellipitical or circular plane.

The BH must be spinning in axis too, and anything that are caught up in the BH's gravitational field, will not only move towards the BH, but will also be spun around until it reaches the core centre of the BH, like a whirlpool.

But while the BH would cause matters and energy to be spun around its orbit, some of the waste matter or energy would be ejected from the two poles.

The scientist, Stephen Hawking, believed that the Black Hole will spit out from the two poles of the BH, mostly energy, but could also be waste matters. They are ejected from the BH with great force and velocity.

I am not talking about wormholes, which is more science fiction than anything else, but ejection of materials or energy out of the bh is one of the theories yet to be proven.

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do you have a source for this information? the closest i've ever heard to that is that if you travelled to jupiter and back at near the speed of light, the people back on earth will think you were gone for a different time than you think you were gone.

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There are two different theories, both true that play with space and time:
these are "Special Relativity" and "General Relativity".

The first one deals with space and time dilation while you are moving at high velocities.
So a flight pilot will gain some seconds more above us.
Here the space-time is flat, but there are already four dimensions.

The second one unites energy and mass as one thing, and it says that time goes faster where there's less mass. Here space-time is curved. Energy curves space-time.
So if you spend two years in Jupiter (which is heavier than the earth) you will be come younger than if you lived those years on earth.

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From what I have heard, special relativity didn't take gravity into account, which is where general relativity does.

 joana_z writes...

I have heard differently about mass. As you move closer to the speed of light, you would shrink, but have more mass. How that it can be possible that you'd shrink in size but still gain mass, is a little confusing.

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More infos here

LINK

By the way, if I'm not mistaken, the term 'black hole' was only coined after Einstein's death.