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 rockondon
Joined: 2/21/2007
Msg: 5
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Black holes...help!Page 1 of 9    (1, 2, 3, 4, 5, 6, 7, 8, 9)
The gravitational pull from the center of a black hole is so great that light, which is subject to gravity, will be pulled back in. That's why they're black - light does not escape them. We've been watching black holes for a little more than a decade I believe.

Incidentally, if you want space/time travel you can check out wormholes.
http://en.wikipedia.org/wiki/Wormhole
 innocentlysinful
Joined: 9/13/2006
Msg: 9
Black holes...help!
Posted: 3/7/2007 12:34:47 PM
They don't exist, least no one has visited one, or has any physical proof.

Black holes are a theory, subject to be reinvented at any time.

Even Stephen Hawking changed his theory on black holes recently.

Black holes, like many other hollywood creations ie: warp speed, hyper space.. etc

All fictional at the moment...
 innocentlysinful
Joined: 9/13/2006
Msg: 11
Black holes...help!
Posted: 3/7/2007 12:55:52 PM
Not exactly, Hawking - the basis of almost all of black hole theory used to feel thet nothing escaped from a black hole. (which all of the world accepted as canon, praised and held aloft for all to see a fact)

Recently he changed his theory that black holes convert matter to enegry to allow it to escape out the other side...

So is he right? or is he wrong?

We can't even figure what came first a chicken or an egg and we can physically interact and alter these things.. how can we even begin to prove an idea that we cannot even see, let alone pysically witness in any way...

Specially when the guy who invented it keeps changing the rules to keep himself employed...
 2findU
Joined: 11/19/2005
Msg: 13
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Black holes...help!
Posted: 3/7/2007 3:28:49 PM
The Black Hole is what is beyond the Event Horizon. That is the distance from the singularity where the escape velocity exceeds the speed of light. That is what makes the hole "Black". The singularity is a mathematical point that takes up no space where all the mass collapsed into infinite density. For example if the Sun collapsed (yes, I know it doesn't have enough mass for a gravitational collapse) into a singularity its event horizon say may be equal to the Earth's diameter. But the Earth and all the other planets would still remain in orbit because the gravitational interaction has not changed. It is only when you get too close to the Event Horizon where gravity gets incredibly strong and tidal forces will rip you apart before you get sucked into the Event Horizon. I hop that explains some of it for you.
 rockondon
Joined: 2/21/2007
Msg: 14
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Black holes...help!
Posted: 3/7/2007 5:36:48 PM

They don't exist, least no one has visited one, or has any physical proof.

Black holes are a theory, subject to be reinvented at any time.

Even Stephen Hawking changed his theory on black holes recently.

Regardless of whatever it is that Stephen Hawking does in his spare time, the existence of black holes is a virtual certainty. You are correct that no one has visited one, and even if they did they wouldn't be here to testify, but there is a considerable amount of proof of their existence. One of the black holes in the milky way is in Sagittarius A. Here's some (not very good) pictures of a few more. http://csep10.phys.utk.edu/guidry/violence/active.html

Pictures never do a black hole justice since they don't emit light and are usually too far to see well anyway. Generally we 'see' a black hole by observing the effects of its gravitational pull on its surroundings.

Incidentally, a "theory" takes on a difference of meaning depending on the context in which it is used. In casual conversation, one could make up something ridiculous and call it a theory. In a scientific context a theory is defined as "a coherent group of general propositions used as principles of explanation for a class of phenomena" (or in layman's terms, it is something that explains facts).
For example, gravity is a fact, and the explanation for how it works is a theory. A scientific theory in no way implies uncertainty - quite the opposite; a scientific theory has withstood enormous scrutiny from countless others trying desperately to prove it wrong.
 CountIbli
Joined: 6/1/2005
Msg: 15
Black holes...help!
Posted: 3/7/2007 8:13:42 PM
Don't think of Black Holes as holes. They're more like vaccuum cleaners.
 2findU
Joined: 11/19/2005
Msg: 16
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Black holes...help!
Posted: 3/8/2007 4:58:03 PM

They don't exist, least no one has visited one, or has any physical proof.


"No one has visited one" That's a good one. The furthest we've been able to send humans has been the moon. Mars will be next. Black holes are many light years away. Even if we could send a probe it would take centuries to get there and centuries and as many years to get a signal back as it is in light years of distance away. And we would never hear back from it because it would be a one way trip. There is plenty of scientific evidence for the existance of black holes. And Einstein thought of it, not Hawking. Hawking has done further research on it.
 Augiedougie
Joined: 1/10/2007
Msg: 18
Black holes...help!
Posted: 3/9/2007 1:35:35 AM
Black holes were 'discovered' as a theoretical object in the late 1700's or early 1800's as an exercise to find out if the Newtonian Theory would be able to calculate at what mass and volume would not allow light to escape.
I don't remember who it was but I do remember reading a number of years ago of a physicist who was playing with Newton's equations as a exercise only.
As Black Holes being theoretical and never been observed directly, that is true. You cannot see a black hole by definition. You can measure its effect on the surrounding space.
What happens to material that enters the black hole, no one knows either. The known mathematics for calculating what happens totally breaks down.
 2findU
Joined: 11/19/2005
Msg: 24
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Black holes...help!
Posted: 3/9/2007 4:11:50 PM

That is the distance from the singularity where the escape velocity exceeds the speed of light.


Actually is it not at the Event Horizon where nothing including light can escape. The singularity is that point right in the center where the most density where ALL the matter and other things end up. The Event Horizon represents the point of no return for anything including light.


Thanks, that's what I meant to say.
 Augiedougie
Joined: 1/10/2007
Msg: 25
Black holes...help!
Posted: 3/10/2007 9:20:34 PM
Thank you, Sombient!
 doza2007
Joined: 3/7/2007
Msg: 26
Black holes...help!
Posted: 3/12/2007 9:52:17 AM
A Black Hole is the singular absence of all matter and energy. The absense of all matter is called a Vacuum, and it will immedaitely draw in all matter it possibly can to rebalance itself. The same thing applies to Black Holes, the black hole draws in any source of energy that it can - including light - until it can rebalance itself. Then it, adn the energy simply disapeers, there energy is not there, it never was. The black hole is a disagreement to the laws of physics. Anything pulled into the black hole ceases to exist and never existed at all. A parodox was created, so the law of physics changes iteself thereby meaning that the enrgy that caused the laws of physics to change, get this, it never existed, so it never changed at all. I dont know if anybody else can understand this paradox, but i can.
 rockondon
Joined: 2/21/2007
Msg: 29
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Black holes...help!
Posted: 3/13/2007 12:45:19 AM

The same thing applies to Black Holes, the black hole draws in any source of energy that it can - including light - until it can rebalance itself. Then it, adn the energy simply disapeers, there energy is not there, it never was. The black hole is a disagreement to the laws of physics. Anything pulled into the black hole ceases to exist and never existed at all. A parodox was created, so the law of physics changes iteself thereby meaning that the enrgy that caused the laws of physics to change, get this, it never existed, so it never changed at all. I dont know if anybody else can understand this paradox, but i can.


what
 doza2007
Joined: 3/7/2007
Msg: 32
Black holes...help!
Posted: 3/14/2007 8:28:26 AM
Exactly, X-rays are radiation. Radiation is Nuclear energy. They will get pulled in aswell.
 rockondon
Joined: 2/21/2007
Msg: 33
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Black holes...help!
Posted: 3/14/2007 9:06:25 AM
X-rays are one of the most compelling pieces of evidence for proving the existence of black holes. X-ray binaries (stars that emit large amounts of X-rays) spew out X-rays that are drawn in and captured by black holes.


Exactly, X-rays are radiation. Radiation is Nuclear energy. They will get pulled in aswell.

Black holes are believed to emit a thermal radiation (call Hawking radiation) due to quantum effects. Black holes that emit more matter this way than they gain through other means will actually shrink. However, the existence of Hawking radiation is controversial.
 doza2007
Joined: 3/7/2007
Msg: 34
Black holes...help!
Posted: 3/14/2007 10:29:54 AM
Even if it is controversial, it is still an interesting topic of discussion.
 whatuwhispered
Joined: 10/2/2006
Msg: 38
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Posted: 3/20/2007 9:00:12 PM
You should go check out some of the info on supermassive black holes which are basically black holes containing millions to billions of solar masses. One is suspected to be right in the middles of our galaxy. Its amazing how much we have learned about these in the last 40 years.
 rockondon
Joined: 2/21/2007
Msg: 42
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Black holes...help!
Posted: 3/22/2007 10:23:10 AM

Actually there is something that is faster then light and that is the "speed of SIGHT".....meaning as you know, when we look up into the stars, it takes our vision or siight to reach those stars for us to receive the feedback, it takes it about 100th of a second, or under one second either way.

Unless I'm misinterpreting something, you make it sound like our eyeballs are exuding something that reaches those stars.
When we see something, its because light is entering our eyeballs (at light speed, with minor speed variations depending on the medium - air, water, etc.), not because our eyeballs are radiating sight rays that extend outward.
So when we see something that is 100 light years away, our sight isn't travelling that far to observe that phenomena, that phenoma radiated light that travelled 100 years to reach us.
 JustJanie
Joined: 1/15/2007
Msg: 46
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Black holes...help!
Posted: 3/23/2007 9:27:59 AM
2FindU...

"No one has visited one." Yes, that was funny. I have been reading your posts and want to thank you for your elegant explanation of an important part of what one day be The Unified Theory.

I do not like Hawking. I don't consider him a true physicist - more like a mathematician with a bad attitude...

And, yes...I do have my own personal unified theory. Don't we all...LOL

Regards from New York...
 JustJanie
Joined: 1/15/2007
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Posted: 3/23/2007 9:32:47 AM
Isn't that what Hawking backed down on...?
That light could not escape...

When you say escape...do you mean light somehow got in there and now cannot get out..?

Jane
 JustJanie
Joined: 1/15/2007
Msg: 48
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help!
Posted: 3/23/2007 9:36:12 AM
There is a Black Hole in the middle of every galaxy....

You are right - something new all the time...

Hurray for the Hubble Telescope<3

Jane
 JustJanie
Joined: 1/15/2007
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Posted: 3/23/2007 9:39:24 AM
General Relativity (or at least a portion of it) will be kicked to the curb, if not in our lifetime, but soon enough...

And of course something can exceed the speed of light. We just don't know what it is yet...

Jane
 Augiedougie
Joined: 1/10/2007
Msg: 52
Black holes...help!
Posted: 3/23/2007 1:48:29 PM
And of course something can exceed the speed of light. We just don't know what it is yet...


It is theoretically possible to exceed the speed of light (or c), but let me qualify that first.
In the theory of general relativity the divisor of the eqation approaches zer0 as you approach the speed of light. (The square root of 1 - 1/c squared) This causes the amount of energy and mass to increase greatly as you approach the speed of light. Once you hit the speed of light this divisor is zero. This makes the answer infinity. Something that impossible to reach.
When your speed is over the speed of light the divisor becomes the square root of a negative number which is an imaginary number.
It is therefore theoretically possible to travel faster than the speed of light if you can find the root of a negative number (which does not exist) but you cannot travel at the speed of light itself.
 MrGuyCaballero
Joined: 2/27/2007
Msg: 54
Black holes...help!
Posted: 3/23/2007 10:31:42 PM
Just to try and clarify the discussion on light and vision again, imagine vision as working like hearing. We don't hear things by sending out something from our ears. Our ears just accept waves (intervals of high and low pressure in this case) coming to us through the air. Our auditory system then tells us , "hey, something is over there making noise". That's how our eyes work, too. Instead of receiving audio waves, they receive light waves (photons). As stated above, we see QQQ 1432 as it existed about three billion years after the Big Bang instead of how it exists now. If there was something going out from us to QQQ 1432 in a fraction of a second, then what we saw would not be so far behind the present. And we would be able to see things that don't emit anything at all, which is not the case. You may ask, "then how do we see black holes?" The answer is "we don't." We see only their surroundings.

Now, to potentially blow some minds. As has been stated, relativity states that nothing can travel faster than the speed of light. But, did you know that things can actually move away from you at speeds greater than the speed of light? Sounds like a paradox, right? It's not. Due to the expansion of the universe, it is possible for objects to recede from us a greater than the speed of light. Think about it this way. Consider two regions of space. Our galaxy is in one and Galaxy Z is in the other. The space itself in between them "grows", so to speak, so the two galaxies are then farther away from one another. Now, all that additional space between them is growing then, too, so the rate at which the two galaxies are flying away from one another is constantly increasing. At some point there is enough space (expanding space) between them that light from one can never keep up with the ever-expanding distance between the two. So, no light, no objects, nothing can ever then make its way from our galaxy to Galaxy Z. Still no laws of relativity have been broken because what's essentially happening is that the "regions" themselves are moving while everything in the two regions continues to move at or below the speed of light.
 rockondon
Joined: 2/21/2007
Msg: 57
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Posted: 3/24/2007 12:23:02 AM

is there anyway we can see into teh future from out there....

No. I can think of no way to see into the future, but then again what do I know.

We're not looking into the past, we're just looking at old light. That light emanated from events that happened before, and they to0k X amount of time to reach you. So when you look up at the stars, you're not watching a live performance.

So if you remain still and look around, you see the present. If you flew ~2000 light years away from earth and maintained light speed away from it, you could look back and watch the crucifixion of Jesus.
If you took the happiest moment of your life and flew away from it at light speed, you could watch that moment forever. You'd need a pretty good telescope of course.

Incidentally, from what I understand nothing moves faster than light. If you are in a train that is moving at light speed, and you then you speed up - you're moving light speed. If you are in the train (still at light speed), and you personally travel from the back of the train to the front of the train, both you and the train are moving at light speed, even though you're moving faster than the train. The speed of light remains the same for all observers.
That's relativity.
I don't understand it either.
 MrGuyCaballero
Joined: 2/27/2007
Msg: 59
Black holes...help!
Posted: 3/24/2007 2:08:23 PM

What do you mean here?

I was able to see another Galaexy , I remember when this was it was in July in 1995 I was up north and in the clear sky there we say what appeared to be spirals far far away and they were very faint, we said to ourselves (my friends and I ) we said that that was another galexy.

Besides astronomers can see different galexies via telescope. So appearantly light CAN travel that fast.

Yes, we can see other galaxies, but those are not far enough away for what I was talking about to come into play. I don't know what the critical distance is, but no matter where you are, you could point in any direction and say, "anything ______ miles in that direction can never be observed by us, and nothing beyond that distance can ever observe us." This assumes no wormholes, etc.
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