Are you interested?
may be we should have a thread, discussing them?
and share opinions.
whatcha say?
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Are you interested?
may be we should have a thread, discussing them?
and share opinions.
whatcha say?
What is the exact meaning of black holes?
I suppose that they are some kind of code that produce a no-exit result?
Is this true?
I believe BHs exist...
A black hole - the ultimate file deletion utility.
i thought he was talking about real black hole in the space...:confused:Quote:
Originally posted by Dave McLelland
A black hole - the ultimate file deletion utility.
How about wormhole, white hole crest etc.
It is a long time since I saw Contact... maybe I will see it again today and post something ..:D
I tried to start a thread to discuss the black hole in my head, but
it got no where.
What in the **** are Black Holes????
A black hole is like a database, you put stuff in you can never get it back. :rolleyes: You know its there because its mass increases.
A black hole is the ultimate encryption device.
A black hole is the ultimate decryption device. It holds tight a public key...You must know that truth... :cool:
When I think of a black hole I think of....
The thing about black holes is, they're not as tough as they look. Most of the time you can just intimidate the black hole into being subservient. Even if it did try to suck you in, it would take you forever to fall in. I think a funny prank would be, go over to your friends house with a black hole in your pocket, then when he goes to the bathroom or something take it out and his whole house gets sucked in along with his furniture and valuables and stuff, and when he comes out he just has no clue what happened.
Deep Thoughts by ... SolarFlare...Quote:
Originally posted by solarflare
The thing about black holes is, they're not as tough as they look. Most of the time you can just intimidate the black hole into being subservient. Even if it did try to suck you in, it would take you forever to fall in. I think a funny prank would be, go over to your friends house with a black hole in your pocket, then when he goes to the bathroom or something take it out and his whole house gets sucked in along with his furniture and valuables and stuff, and when he comes out he just has no clue what happened.
Quote:
I bet a fun thing would be to go way back in time to where there was going to be an eclipse and tell the cave men, "If I have come to destroy you, may the sun be blotted out from the sky." Just then the eclipse would start, and they'd probably try to kill you or something, but then you could explain about the rotation of the moon and all, and everyone would get a good laugh
It occurs to me that the more stuff you put into a black hole the bigger it gets. No other hole has that property. Maybe it should be called a black heap.
Its properties are defined by how much stuff there is. An ordinary hole is defined by how much stuff there isnt!
:p (click)Quote:
Originally posted by Mick_2002
Deep Thoughts by ... SolarFlare...
Black Hole!
its not black really :o
hmm...
acc to s/w deptt of our cmpny, a BH is an app which came to existence after the Big Bang with the Folkz in Mgmnt. It consumes all the resources it can find and uultimately crashes down and leaves nothing ... absolute space...
horrible...
i started this thread to see how many are interested in Real BH, but seems nope, no one. :)
anyways, nice to hear the views tho' ;)
Black holes don't exist.
Actually I like Blackholes in universe very much...It is a myth, unexplainable truth to me...As I have said in my first post I believe its existence...:)Quote:
Originally posted by andy_tacker
Black Hole!
its not black really :o
hmm...
acc to s/w deptt of our cmpny, a BH is an app which came to existence after the Big Bang with the Folkz in Mgmnt. It consumes all the resources it can find and uultimately crashes down and leaves nothing ... absolute space...
horrible...
i started this thread to see how many are interested in Real BH, but seems nope, no one. :)
anyways, nice to hear the views tho' ;)
It s nice to hear you also like it...I like to know about it too...:)
Here is a picture of a black hole:
Black Hole
In the Yilmaz version of relativity theory, black holes can't exist. There is also this Hungarian guy I think who says they are impossible, only in the limit a very compact object can be like a black hole as described in the Schwarzschild solution.
My brain hurts now.Quote:
Thus the Yilmaz theory predicts that relativistic effects should distort space in such a manner that the universe expands locally about every point in the universe, yet the size of the universe does not change.
BTW isnt Cygnus X1 confirmed as a black hole.
It is only confirmed NOT to be a neutron star, with the current understanding of quantum mechanics. It is believed that if black holes exist (the majority of the scientific community believes this), Cygnus X1 is a black hole.Quote:
Originally posted by Dave McLelland
My brain hurts now. BTW isnt Cygnus X1 confirmed as a black hole.
I don't know how to interpret that either, but I have an idea: if everything expands, also the tools you use to measure distance, how do you know the distance has increased?Quote:
Thus the Yilmaz theory predicts that relativistic effects should distort space in such a manner that the universe expands locally about every point in the universe, yet the size of the universe does not change.
I always wondered if there is an end to the universe... and what would it be like ..like a brick wall...etc
But I always end up beliving that there can be no end.
Maybe the universe is like a Pacman level: if you get out on the left, you come in on the right again :)Quote:
Originally posted by voidspace
I always wondered if there is an end to the universe... and what would it be like ..like a brick wall...etc
But I always end up beliving that there can be no end.
Probably there is no end as I read that our universe is still expanding.Quote:
Originally posted by voidspace
I always wondered if there is an end to the universe... and what would it be like ..like a brick wall...etc
But I always end up beliving that there can be no end.
Could be if the universe is curved in more dimensions, so far no such indication has been found. What you're saying is possible if the universe we know is the surface of a 4D sphere for example I guess.Quote:
Originally posted by Gabriel Fleseriu
Maybe the universe is like a Pacman level: if you get out on the left, you come in on the right again :)
Quote:
Originally posted by CBasicNet
Probably there is no end as I read that our universe is still expanding.
Yes...but it must be expanding into something
.................................................|
.................................................|
............... ....Universe end point-->|
.................................................|
.................................................|
.................................................|
But the other side would always exist and it is to have something like black holes or whatever ...but there would be something beyond it ..so it has no end.
Well, for the question of the universe's boundaries, there are several options currently promoted. As Simon has pointed out, the universe may be topologically a 3-sphere (a sphere with a three dimensional surface), and this has been a prevalent belief ever since Friedman, Robertson, and Walker derived from general relativity this as a possible solution. Then, the universe could have a finite volume, but there would be no boundaries (like pac-man!). Einstein liked this solution alot, and work in the late 60's and early 70's showed such solutions to be fairly general. However, recent WMAP evidence tends to show that the curvature of our universe is very close to zero, which would imply an infinite universe. This is an alternative possibility, also one of the Friedman-Robertson-Walker solutions, though it might require very precise conditions of the universe for this to happen. Again, however, there is no boundary, and in fact, there is very little support in the science community that the universe would have a boundary since it is very difficult to get boundary conditions from general relativity that are consistent. However, it is likely that general relativity is only an approximation to some better theory, since it does not possess the proper mathematical structure to be compatible with quantum mechanics. For example, modern M-Theory predicts an 11 dimensional space-time with many of those dimensions coiled up so small as to have been undetected. Loop Quantum Gravity is another modern attempt at a consistent quantum theory of gravity, and though not yet well developed, another possibility (which overlaps both M-Theory and LQG) is non-commutative geometry. These are the only modern theories which can claim some sort of consistent quantisation of general relativity, and all of them show GR to be only an approximation. However, only recently have physicists been able to solve these theories for solutions of the global space-time geometry, and choosing the solutions that correspond to what we actually observe is very difficult.
Now, concerning black holes. They seem to be legitimate solutions to the evolution of dense cosmological structures, but their existence is still somewhat debated. However, since there are objects out there that behave exactly as black-hole predictions say they should (violent x-ray sources due to accretion discs, the "cosmic jet" events detected at galactic cores, the lack of luminescent objects where these events are occuring, mass estimates that fall within the black hole density range, etc.), alot of the debate seems centered more on just whether to call them black holes or not. Either way, there are certainly objects out there that behave a lot like black holes.
I am not sure, however, what to discuss about black holes. I am certainly interested in them. Maybe a topic list could help.
- The Schwarzschild and Kerr-Newman solutions to the Einstein equation.
- The "naked singularity" no-go theorems.
- (My favorite) The "no hair" theorem.
- Black hole thermodynamics (entropy, black-body radiation, etc.)
- The recent work in superstring theory on reformulating the language of black holes.
- The black-hole "disproof" of the Church-Turing thesis.
- Some of the more strange possibilities like the Kruskal extension and white holes.
- The black holes that Mick was alluding to...
Those are some options for discussion. I just don't know where to begin.
Look what has science ever done for humanity??? There are people starving all over the world, think about the children??? Lets get rid of NASA, they haven't done a single thing for our children....GM crops, GM crops...why no I won't eat GM crops, even though I'm starving....ohh the humanity...the horror, science needs to go, go, go....you are cruel you are evil...where's my tree to hug???Quote:
Originally posted by galathaea [*] The black holes that Mick was alluding to...[/list]
Those are some options for discussion. I just don't know where to begin.
/"I say we let him go!"
//Nobody expects the spanish inquisition!!!
I hope you are kidding. In the last sentence though, you are definitely right.Quote:
Originally posted by Mick
Look what has science ever done for humanity??? There are people starving all over the world, think about the children??? Lets get rid of NASA, they haven't done a single thing for our children....GM crops, GM crops...why no I won't eat GM crops, even though I'm starving....ohh the humanity...the horror, science needs to go, go, go....you are cruel you are evil...where's my tree to hug???
/"I say we let him go!"
//Nobody expects the spanish inquisition!!!
My favorite universe model is the hypercube, but maybe only because there's such a cool story about a hypercube.
(hypercubes)
("And He Built a Crooked House" - Rob't Heinlein)
solar solar solar, when have I not been dripping with sarcasm???Quote:
Originally posted by solarflare
I hope you are kidding. In the last sentence though, you are definitely right.
My favorite universe model is the hypercube, but maybe only because there's such a cool story about a hypercube.
(hypercubes)
("And He Built a Crooked House" - Rob't Heinlein)
Oh, so you do want the yankees to win? I knew you'd come around eventually.Quote:
Originally posted by Mick
solar solar solar, when have I not been dripping with sarcasm???
well dont we call it Space-Time and its not spherical at all :)Quote:
Originally posted by galathaea
As Simon has pointed out, the universe may be topologically a 3-sphere (a sphere with a three dimensional surface)
the problem with BH is that they work against all the laws of physics. that means, they dont obey any of the laws of physics. would that mean that us, humans at earth, are missing some elementary law? once that law is found, the mystery of BH will be solved.Quote:
Now, concerning black holes.
The question about their existence is rather groupable! that would mean, a group believes in their existence, others dont. but that's a debate. every thing was intially debated. even that the earth is round :)
so, there are several topics of discussions for those who believe in their existence. and simply share the thoughts and share new information.
for those who dont beleive in BH, I would recommend starting up with ....
...
In a Black hole times ceases to exist...how is this possible? Because time is something that will always go on..
A black hole is the ultimate abyss. You can't escape and you can't die. :cool::cool::cool:Quote:
In a Black hole times ceases to exist...how is this possible? Because time is something that will always go on..
Oh, and look at my status, please, everyone. Yes, the text above my saintly avatar. :o:o:cool:
<<A black hole is the ultimate abyss. You can't escape and you can't die. :cool::cool::cool:>>
Oh yes you can, the gravity force near the regular size black holes would tear you right to pieces before you even notice any time dilatation effects.
I could have sworn Tom posted something here...
Well, I would make a distinction. The black hole itself was predicted using the laws of physics, explicitlyQuote:
Originally posted by andy_tacker
the problem with BH is that they work against all the laws of physics. that means, they dont obey any of the laws of physics. would that mean that us, humans at earth, are missing some elementary law? once that law is found, the mystery of BH will be solved.
Gmn = 8 p Tmn
where G is the Einstein tensor (defined in terms of the Riemann curvature and the metric) and T is the stress-energy-momentum tensor for the matter field studied. However, it is often stated that at the singularity at the center of the black hole, the laws of physics break down. That's true if you consider things like quantum mechanics, but general relativity is not consistent with qauntum mechanics even outside the singularity. Otherwise, the laws of general relativity are consistent. The singularity presents problems with path continuity, but that is a problem with point collisions in general and even shows up in classical newtonian physics.
Well, time does not cease to exist in a black hole. Its just that time has some peculiar properties, and black holes emphasise these peculiarities. The strange properties of time first appeared in special relativity, where it was shown that the time measured to have elapsed in objects depends on how the object is moving relative to the person measuring. This is coupled to a similar property of length, and is due to the fact that the concept of distance was generalised from the space-distances of classical physics to the larger notion of metric distances in spacetime. Transformation laws that preserve the special relativity metric distance (ds^2 = dt^2 - dx^2 - dy^2 - dz^2), do not generally preserve the individual space or time distances. In general relativity, the metric used to measure spacetime distances was changed to one which can vary at every point of spacetime, which allowed the physics to describe motion on curved spacetimes. This allowed Einstein to postulate his equation which described spacetime curvature as a consequence of the presence of matter, and it was shown that gravity could then be considered as something not exactly a force, but merely the natural way that things move in a curved spacetime.Quote:
Originally posted by voidspace
In a Black hole times ceases to exist...how is this possible? Because time is something that will always go on..
Now, black holes have a strange metric (which for a non-spinning, non-charged black hole is described by the Schwarzschild solution). This metric predicts that there exists this place in space around a very dense object known as the event horizon, inside of which all equations of motions move towards the center (or singularity) of the black hole. This means that even light itself would always travel on paths that do not escape the event horizon. This metric also predicts that someone far away from a black hole would observe something freely falling into the black hole as approaching the event horizon slower and slower, and that it would take an infinite amount of time to for that object to cross the event horizon. However the amount of time needed to cross the event horizon as measured by something actually falling in is finite, and they even would reach the singularity in a finite amount of time in their view. Space-time still exists in the black hole, its just that it is not observable to anyone who does not fall inside in any finite time.
Which brings me to a topic I mentioned in my list, and one that might be of interest to computer scientists, namely the Church-Turing thesis. One can imagine a situation where an object falling into a black hole is able to destroy the black hole (perhaps by firing an amount of antimatter equivalent in mass to that of the black hole into the singularity) just as they cross the event horizon. In this way, it is possible for one observer to have passed an infinite amount of time with respect to a distant observer while still having travelled for only a finite time in its own reference frame. Now, if that distant observer were to run a program that was to send a signal to the object falling in if it finishes its calculation, and otherwise remain quiet, the object falling in would know in a finite time if that program ever finished. This is the computational problem known as the halting problem, and it has been shown that the halting problem is not Turing-computable. However, this setup shows that there exists a solution to the halting problem, and thus not all "effectively computable" problems are equivalent to Turing-computable problems (which was the postulate of Church and Turing). Its a weird solution and not at all practical, but it does show that black holes give some very interesting mathematical results when applied to areas that would seem not even remotely related.
And just a note:
I am in no way stating that I "believe" in general relativity or the solutions I am stating. I am only stating that the mathematical models have been shown to be consistent with the observations we are currently able to make and have even predicted results that no previous models were able to (such as the example of the precession of Mercury's perihelion given in most introductions to general relativity).
However, I try to follow as many alternate theories as I can find. That was even one of my concentrations when I was studying philosophy in college (which was a dual major of mine). For example, I absolutely love Bohmian mechanics, and have even recently begun to "bohminise" various string theories and other modern quantum theories (I have a thread I posted recently on sci.physics.research on just this topic -- which unfortunately has garnered no responses). I have even visited the site on Yilmaz's theory which Simon posted, and am currently trying to discern what predictions the model makes and how they may be supported / falsified. However, right now one problem I see is that the matter-creation-through-expansion concept seems to be just a version of the Brans-Dicke cosmology proposed in the 50s, which has faced alot of experimental problems due to the lack of detection of such signatures. Its still not completely resolved in the general case, but the revisions needed seem to so far face mathematical problems in invalidating other predictions, and I have yet to see a mathematical model that can maintain consistency to all observations. However, I do want to check out whether the Yilmaz theory accomplishes some of these consistency requirements.
In fact, I thinks it pretty clear that the current frameworks of general relativity and quantum mechanics do not work together consistently, and that new physics is required. With experiments showing the possible existence of dark matter and dark energy not currently predicted by any model, physics is not yet (and I would say, nowhere near) reveling the naked body of "truth" yet. It remains to be seen whether black holes will survive the necessary modifications, but I think that the observational evidence of objects that behave very much like black holes and their existence not very close to the realm where we believe the physical models to be incorrect (except at the singularity -- which does not require the modification of the notion of an event horizon), I think they are currently about as likely as the neitrino having mass. Even superstrings and M-Theory (which do unite quantum mechanics and general relativity in a consistent fashion), predict black holes and even give some new mathematical models for describing them.
good post great read galathaea!
But my knowledge on the subject is little but my facination is more ..:rolleyes:
Anyways all this seem to boil down to proving that time can be controlled ... has anybody proved this ..
Like move time forward or backward at will (except in those hollywood movies back to the future and Time Machine)
The last time heard about it (controlling time) was when someone did an experiment using very long tubes ..ahhh can't remember after that :(
Black holes are gravity wells, therefore, slow time. Black holes are the ultimate gravity wells, therefore, no time.
What the...??? How in the...???Quote:
Originally posted by Saint Xeon
Oh, and look at my status, please, everyone. Yes, the text above my saintly avatar.
How can you notice time-dilation effects unless you're looking in from the outside?Quote:
Originally posted by Simon666
Oh yes you can, the gravity force near the regular size black holes would tear you right to pieces before you even notice any time dilatation effects.
If the time is somewhat STOPPED in BH, can we be saying that travelling through BH (given you stay alive and dont get DEFORMED :) cos of Gravity) where will it lead?
How true is the fact that they might be a gateway to other worlds?
and if the gravity is so big out there, then if we found one in our Milky way, would we be able to travel to other universes using this gravity as a possible way to gain speed for human made satallites?
<<How can you notice time-dilation effects unless you're looking in from the outside?>>
If you look at outside stars and notice a fase shift towards blue. And you should also notice the stars are "moving" toward a position that is opposite to the direction you're falling. Or if you notice an observer not falling in the black hole who seems to age/move more rapidly...
Kurt Godel, among the many things he did, provided one of the
few solutions to the general relativity equations. His solution
does in fact provide for the possibility of time travel, but is
not seen as a realistic solution. By the way, his favorite movie
was Snow White and he starved to death because his germ
phobia prohibited him from cooking for himself when his wife
was ill in the hospital. Some tidbits on one of giants of 20th
century thought.
The beautiful concept of Event Horizon (EH) is the most appropriate answer here. As far as i came to know about BH, the time changes its speed [oh how bizarre is that]. So, someone stading on Event Horizon will see things differently, than someone who is standing far away from there and one who is inside BH.Quote:
How can you notice time-dilation effects unless you're looking in from the outside?
I also remember Roger Penrose's comments on time-dilation. he was giving an example of a Rocket being launched from some planet, and being watched from Earth. so, at the time, when the rocket is being launched, the people on earth would be only seeing how the preparations are going on... there is whole theory presented my Penrose. Hope I would see it again and write it down a little to describe time-dilation.
I know there is time-dilation, what I meant by that is with only one vantage point, there is no reference.
eww, I want in....
A black hole is a object who's mass is so great that light can not escape it gravitational pull...
If you believe in space time being curved, then you would look at it as the gravitational pull is so great that space folds in on itself so light never makes it out and if you believe that photons have a mass, then gravity would pull the photon back down....
But either way, we have seen partials gravitate towards each other (ie. the planet earth you're sitting on), we also know that the more mass the planetary object (ie, sun vs Jupiter) that the greater the gravitation pull is going to be.
And we have seen light bend around planets and around our own sun, so we know that gravity effects it.
The only two things you can have for that are:
A. Space time is curved and photons don't have mass (yet they for some reason have momentum....)
B. Or you believe that photons have mass (which explains the momentum) and we already know what gravity does to objects with mass....
So eventually gravity will get so intense that light wont escape it...
And as for the time dilation nonsense, that's just silly. Einstein's theories and the various others are speculation about things that he and others couldn't possibly understand. Unfortunately, this is one of those cases where science and religion intersect. When people follow blindly just so they can be closer to 'god'.... or in science's case, follow blindly cause they can feel they are smarter...write a pile of dribble down on a piece of paper to confuse the **** out of everybody ( or in my case post it on the internet :) ) and they call you smart....I think thats sad....
:) Thanks, I love to vent about modern science misconceptions
aaah, Solar, can you be more clear. At this time of my day, my mind becomes soooo .... [hehehehe, understand?]Quote:
Originally posted by SolarFlare
I know there is time-dilation, what I meant by that is with only one vantage point, there is no reference.
1 <-> well, how silly the idea might be? all i would comment is that certain things just happen. there are perfect theories explaining them.Quote:
Originally posted by oktronic
1. And as for the time dilation nonsense, that's just silly.
2. Unfortunately, this is one of those cases where science and religion intersect.
2 <-> Science and religion came long way. I think the base of science had been religion. The Gods which turned out to be plantes and natural happening whic turned out to scientific. and there is no such intersection in here. the only difference is the way they are Representing this view. does it makes any sense? the ulitmate destination is same. some call God, some call "Ulitmate intelligence" and some like me simply call it "singularity".