Something of black hole

[alokmohan]

http://thetartan.org/2007/2/26/scitech/workHow Things Work: Black Holes<br />Sci/Tech | Sarah Mogin <br /><br /> <br />Courtesy of NASA/JPL-Caltech<br />Black holes exert gravitational forces on objects that bring them to the singularity, or center.<br />More Sci/Tech Stories<br />Pitt develops molecule that fights cancer cell growth <br />Professor makes presentation on carbon control policy <br />SciTech Briefs <br />How Things Work: Black Holes <br />More »<br /><br />Up there with the aliens from War of the Worlds, black holes are probably some of the more terrifying aspects of the universe.<br /><br />Black holes form following the deaths of massive stars.<br /><br />Throughout their lifetimes, stars are subject to their own gravitational fields in space. The gravitational fields create forces on the star.<br /><br />One would expect this force to cause the star to collapse inward. However, there is an equally strong force in opposition to this gravitational force.<br /><br />Elements of a star<br /><br />This latter force is caused by the fusion reactions taking place within the star. For the majority of the star’s lifetime, hydrogen fuses inside its core to create helium.<br /><br />When the star’s supply of hydrogen runs out, it becomes a red giant. The star initially expands and then shrinks to a helium core, at which point the helium atoms begin to fuse with other helium atoms to form carbon and oxygen.<br /><br />In massive stars (those at least nine times as big as the sun) this process of expansion and contraction keeps going; the red giant phase typically lasts between a few hundred thousand to one million years.<br /><br />Following oxygen, the star produces neon, silicon, sulfur, and then iron. The star begins fusing the element that it has just produced after each expansion and contraction.<br /><br />At the end of its life, the star will fuse multiple elements at once in onion-layer shells. The outermost

 

[nexium]

The above hints of several things that likely are not true. The "at least nine times the mass of our Sun" is likely wrong. While we are conceeded to describe the physics near the sigularity, it seems probable that nothing happens (short term) to a space craft that passes inside the event horizon of a super massive black hole. I would not expect that it would accellerate (including change direction) to much faster than c to reach the singularity in less than ten seconds. Neil

 

[alokmohan]

Not likely wrong,IT is wrong.When I posted I over looked it .Thank you.When we have a star more than at least three solar masses we get a black hole.This may be much higher figure,I dont know.These are called stellar black hole.Supermassive black holes may be million or even billion times solar mass.They are beleved to in center of galaxies.May be in quasars also.

 

[alokmohan]

Can you tell me what is a quark star?

 

[lukman]

Quark Star <div class="Discussion_UserSignature"> </div>

 

[alokmohan]

Very useful info.Is it alternative of black hole?Do these rule out black hole?Disuss about exotic matter also.

 

[docm]

They are not an alternative to a black hole, but something denser than a neutron star and less dense than a black hole. Just dense enough to create a quark soup. <div class="Discussion_UserSignature"> </div>

 

[alokmohan]

Are black holes,quarks stars real:any bit of indirect evidence?

 

[enigma10]

<i>Quark stars and strange stars are largely theoretical at this point, but observations released by the Chandra X-Ray Observatory on April 10, 2002 detected two candidates, designated RX J1856.5-3754 and 3C58, which had previously been thought to be neutron stars. Based on the known laws of physics, the former appeared much smaller and the latter much colder than it should be, suggesting that they are composed of material denser than neutronium. However, these observations have been under attack by researchers who say the results were not conclusive; it remains to be seen how the question of quark star or strange star existence will play out. Recently a third star, XTE J1739-285 [1], has been observed by a team led by Philip Kaaret of the University of Iowa, and also reported as a possible candidate.</i><br /><br /> Was in the link already provided.<img src="/images/icons/smile.gif" /> <div class="Discussion_UserSignature"> <em>"<font color="#333399">An organism at war with itself is a doomed organism." - Carl Sagan</font></em> </div>

 

[search]

Quark stars candidates:<br /><br />XTE J1739-285<br />This Neutron Star shows X-ray bursts and rotates with 1122 revolutions per second. This is the speed record for rotation. It is accelerated by gas falling in from a near partner star. Possibly it isn't even made of neutrons, but of free, extremely dense quarks. Because at this rotation speed neutrons would separate from each other and the star would fall apart. But this is very debatable. <br />Constellation: Ophiuchus<br />Distance: 39 000 light-years<br /><br />3C58<br />3C58 (aka 3C 58) is a pulsar and surrounding synchrotron nebula within the Milky Way that is possibly associated with the supernova SN 1181.<br />3C58 is notable for its very high rate of cooling which was unexplained by standard theories of neutron star formation. It is hypothesised that extreme conditions in the star's interior cause a high neutrino flux, which carries away the energy and the star cools[1].<br />It is located in the direction of Cassiopeia and is estimated to be 10,000 light-years away. 3C58 has been proposed as a possible quark star.<br /><br />3C58

 

[alokmohan]

So I get a notion of real quark star.Thanks SEARCH it useful post.

 

[alokmohan]

Enigma have you fallen in a black hole.

 

[R1]

how about black rings or black donuts?<br /><br />I hadnt thought about that, but I was just reading something on black rings and possibly more<br />stable black donuts.<br /><br />I think these would involve more than 4 dimensions, and a high spin is more than<br />likely a requirement.<br /><br /><br />It seems that a black ring spins so fast that its centrifugal force keeps its gravity from collapsing it.<br /><br /><br />so much for a simple schwarzchild radius formula. <br /><br />in addition to mass, charge or spin, theres <font color="yellow">shape</font> Has anyone learned much about any of this?<br />It's really so new to me, I think they even mentioned creating a saturn shaped black hole in<br />the new accelerator in Europe.<br /><br />so I wonder, I guess at this rate there might be a black ufo shaped hole somewhere too?<br /><br /><br /> <div class="Discussion_UserSignature"> </div>

 

[alokmohan]

Frankly I dont know.Give a link if possible.

 

[docm]

<blockquote><font class="small">In reply to:</font><hr /><p><font color="yellow"> "Now, my suspicion is that the universe is not only queerer than we suppose, but queerer than we can suppose... I suspect that there are more things in heaven and earth than are dreamed of, in any philosophy"<br /><br />- J.B.S. Haldane</font>p><hr /></p></blockquote><br />Black Saturn's (New Scientist)<br /><br />Paper that started it (PDF): <br /><br />http://ej.iop.org/links/rbA31fqLL/AmtHHgTO2xGS5K-eav5vpA/jhep082005042.pdf<br /><br /><blockquote><font class="small">In reply to:</font><hr /><p><b>Atom smasher may give birth to 'Black Saturns'</b><br /><br />If we ever make black holes on Earth, they might be much stranger objects than the star-swallowing monsters known to exist in space. According to a new theory, any black hole that pops out of the Large Hadron Collider under construction in Switzerland might be surrounded by a black ring – forming a microscopic "black Saturn".<br /><br />A black hole and a black ring can co-exist, in theory, as long as they are set spinning, say Henriette Elvang of MIT in Cambridge, US, and Pau Figueras of the University of Barcelona in Spain. "If you just had a ring, it would collapse. It's essential that it rotates to keep balanced," Elvang told New Scientist.<br /><br />Just like the central black hole, the ring would be defined by its event horizon, a boundary beyond which nothing can escape the object's gravity. The ring could be thin like a rubber band or fat like a doughnut, and the rotation would flatten it – "like a doughnut that you have squashed," says Elvang. The spinning ring would also drag space-time around with it, making the central black hole spin as well.<br /><br />The black Saturn can only exist in a space with four</p></blockquote> <div class="Discussion_UserSignature"> </div>

 

[R1]

great<br /><br /><br />thanks docm<br /><br /> <div class="Discussion_UserSignature"> </div>

 

[alokmohan]

Black hole being black saturn?Speculative too much.

 

[alokmohan]

Please explain black ring more.

 

[docm]

5 dimensional Einstein vacuum calculations allow for a flat singularity; a black ring. There are several ways to get a pairing of point and ring singularities, as long they are rotating. The rotation sets up a repulsion that keeps them separated for the short time it takes them to evaporate.<br /><br />As to if macroscopic pairings are possible, who knows? Recent history would suggest to never say never <img src="/images/icons/tongue.gif" /> <div class="Discussion_UserSignature"> </div>

 

[R1]

thanks docm<br /><br />a black ring would almost definitely be the result of it's spin <br /><br /><br /><br /><br />I wonder what part 'time' plays in the equations.<br /><br />Consider near the center of a plain black hole, point x, where flow of time is = or close to zero,<br />then there must be a point far away from x, point y, such that :<br /><br /> flow of time at y /> flow of time at x<br /><br />with this simple formula, my model, given a certain spin, could easily become<br />like a squished or semi-squished donut as the centrifugal force has greater time allotment at<br />y than at x for the relevant machinations.<br /><br />But this is only my personal opinion based on time . I really don't know yet<br />what the higher dimensions (5 and up) have to do with black shapes, except that<br />there is a correlation being studied.<br /><br /><br /><br /><br /><br /><br /> <div class="Discussion_UserSignature"> </div>

 

[alokmohan]

Higher dimension in so called hyperspace wont be attainale in our universe.So none knows.

 

[R1]

I'm not sure what you're trying to say, but the theorists are studying higher dimensions that are<br />actually evrywhere, space-time would be full of them. Did you see the elgant universe on string theory?<br />there was a good post here somewhere with it.<br /><br />I'm not sure what you refer to as 'hyperspace' I hope it's not some remote place in deep space.<br /><br />The higher dimensions I'm talking about would be essentially everywhere, even here on earth, at least in every area where there's 4D spacetime, it's actually just a deeper department of the first 4 dimensions<br /><br /><br /><br /> <div class="Discussion_UserSignature"> </div>

 

[docm]

"Hyperspace" is often used in fiction as a synonym for Minkowski spacetime; the 4 dimensional mathematical space of special relativity. Another like term is Star Trek's "subspace". <div class="Discussion_UserSignature"> </div>

 

[alokmohan]

We three dimensional are not likely to see it.At least not in this universe.

 

[alokmohan]

The best hope of interstellar travel at present is to create a wormhole taking you from one part of the universe to the other. But such a wormhole would be just as likely to take you to another Universe. Since travelling to another universe is no less likely than travelling to another star, would it not make more sense to own an entire universe? Especially when you can have a universe customised exactly how you want it. http://bordom.net/<br /><br />