why are all the observed stellar remant black hole candiates members of close binary system?
453604
All the observed cases are binary members because we can only observe them by their gravitational influence on other objects close enough to have significant dynamic perturbations of a sustained nature so that we can detect those perturbations. All the other candidates that are not binary members are much harder to detect, but they are out there none the less...
359720
throughout a stars life-cycle, it is constantly heating materials (hydrogen and iron) and pushing them to the surface to cool, and to the center to heat up and melt.\nThis is part of nuclear fission.\n\nafter a very long time, the sun starts to lose energy, and cant push the iron up from its core and gradually grows larger, turning red (hence red giant),\nEventually, the pressure from its mass, and it's failure to push it all away from its core will result in the star collapsing into itself, potentially turning into a black hole.
892778
I think maybe the separation is smaller than the resolving power of my eyes rather than the angular separation of my eyes. So I can't resolve the two sources and just see one bright star. \n\nBest of luck - Mike
437749
Most astronomers believe that the Milky Way Galaxy -- the galaxy in which our solar system is located -- contains millions of black holes. Scientists have found a number of black holes in the Milky Way. These objects are in binary stars that give off X rays. A binary star is a pair of stars that orbit each other. \n\nhttp://www.nasa.gov/worldbook/blackhole_worldbook.html
1021449
A black hole is what remains when a massive star dies. \nThe concept of an object from which light could not escape (e.g., black hole) was originally proposed by Pierre Simon Laplace in 1795. Using Newton's Theory of Gravity, Laplace calculated that if an object were compressed into a small enough radius, then the escape velocity of that object would be faster than the speed of light.\nIf you have read How Stars Work, then you know that a star is a huge, amazing fusion reactor. Because stars are so massive and made out of gas, there is an intense gravitational field that is always trying to collapse the star. The fusion reactions happening in the core are like a giant fusion bomb that is trying to explode the star. The balance between the gravitational forces and the explosive forces is what defines the size of the star. \nAs the star dies, the nuclear fusion reactions stop because the fuel for these reactions gets burned up. At the same time, the star's gravity pulls material inward and compresses the core. As the core compresses, it heats up and eventually creates a supernova explosion in which the material and radiation blasts out into space. What remains is the highly compressed, and extremely massive, \ncore. The core's gravity is so strong that even light cannot escape. \nThis object is now a black hole and literally disappears from view. Because the core's gravity is so strong, the core sinks through the fabric of space-time, creating a hole in space-time -- this is why the object is called a black hole. When material falls into a black hole from a companion star, it gets heated to millions of degrees Kelvin and accelerated.The star Cygnus X-1 is a strong X-ray source and is considered to be a good candidate for a black hole. stellar winds from the companion star, HDE 226868, blow material onto the accretion disk surrounding the black hole.As this material falls into the black hole, it emits X-rays.In addition to X-rays, black holes can also eject materials at high speeds to form jets. Many galaxies have been observed with such jets. Currently, it is thought that these galaxies have supermassive black holes (billions of solar masses) at their centers that produce the jets as well as strong radio emissions.One such example is the galaxy M87.It is important to remember that black holes are not cosmic vacuum cleaners -- they will not consume everything. So although we cannot see black holes, there is indirect evidence that they exist. They have been associated with time travel and worm holes and remain fascinating objects in the universe. There are two types of black holes: \nSchwarzschild - Non-rotating black hole \nKerr - Rotating black hole \nThe Schwarzschild black hole is the simplest black hole, in which the core does not rotate. This type of black hole only has a singularity and an event horizon. \nThe Kerr black hole, which is probably the most common form in nature, rotates because the star from which it was formed was rotating. When the rotating star collapses, the core continues to rotate, and this carried over to the black hole (conservation of angular momentum). The Kerr black hole has the following parts: \nSingularity - The collapsed core \nEvent horizon - The opening of the hole \nErgosphere - An egg-shaped region of distorted space around the event horizon (The distortion is caused by the spinning of the black hole, which "drags" the space around it.) \nStatic limit - The boundary between the ergosphere and normal space \nIf an object passes into the ergosphere it can still be ejected from the black hole by gaining energy from the hole's rotation. \nHowever, if an object crosses the event horizon, it will be sucked into the black hole and never escape. What happens inside the black hole is unknown; even our current theories of physics do not apply in the vicinity of a singularity. \nEven though we cannot see a black hole, it does have three properties that can or could be meas
251633
Because our galaxy has a rotating, supermassive black hole at its center.  As it rotates, the gravitational pull drags all the matter that surrounds it with it, creating the spiral.  I believe this process is the best representation of 'frame dragging' as discussed in some of Einstein's theories.\n\nYou might consider the galaxy as one huge accretion disk spiralling around the central black hole.
670484
To detect a black hole itself is not possible - what you can detect is the radiation caused by matter falling into the black hole. \n\nThrowing matter into a black hole converts matter to energy (e=mc^2) very efficiently, so when you can see point sources of hard x-rays or gamma rays in the sky with no obvious physical source this can be taken to be a black hole. \n\nThe other thing we can do is model how stars age. When all their nuclear fuel is consumed they change form. A star like our sun will convert to a red giant. If the sun were about 3 (?) times as heavy (this is known as the Chandrasekhar limit) it would collapse to form a neutron star. About 10 times as heavy and the matter inside would not be able to stop collapsing and you would end up with a black hole. We can detect this in binary stars where two stars orbit each other. If one star appears to be orbiting something we can't see we can work out how heavy it is and from that decide whether its a black hole or a neutron star.
70857
everything is related to each other if u know the mass, temperature or type of star it is then by using the russell-hertzsprung diagram u can figure out the luminosity
336738
In that picture you are viewing the very bright hot disc of matter spiralling around the black hole. It's called an accretion disc. The black hole is actually at the centre of each disc and is invisible. The accretion discs are far enough from the black hole's influence for the light from them to be able to escape.\n\nYou can't see the black holes; you can see the influence they have on the gas around them.\n\nA previous answer claimed that it was a false-colour picture. While this may be true, bear in mind that some electromagnetic radiation MUST have been intercepted by the telescope or there would be no picture at all.\nThe above picture was probably taken in the x-ray spectrum, since the very hot accretion discs are visible.
84045
A black hole is the collapsed stellar remnant of a supernova (a nova is an entirely different phenomena caused by matter falling onto a white dwarf). Depending on how massive the star is either a white dwarf (lightest) a neutron star (heavier) or a black hole (heaviest) form when a star dies.\n\nType II Supernovas are the catastrophic, yet natural, deaths of massive stars. The star has to be 8 times more massive than the sun to cause a supernova. \n\nOnce a star has used up all of its hydrogen in the fusion processes in the core, there is no more pressure to keep the stars core from collapsing under its own weight. Eventually it gets so hot that the helium begins to fuse which again causes pressure that temporarily halts the collapse. In a star like the sun helium fusion is the end. Once the helium is spent the stars core begins collapsing again while its outer layer puffs out into space leaving a white dwarf. \n\nIn a more massive star carbon fusion, which produces neon and manganese, takes over when the helium is spent because its gravity can cause temperature and pressures great enough. When the carbon is gone the core begins collapsing again. This goes on for several stages of contraction with resulting fusion of increasingly heavier elements. \n\nFinally silicon fuse into iron and the core is the size of earth. The temperature is over 3 billion degrees. No more energy can be produced from fusion as iron is too tightly bound in its nuclei. Instead the iron core collapses with a quarter the speed of light. It shrinks in size from the size of earth to a sphere 100 kilometers across in less then one tenth of a second. This produces gravitational energy 100 times greater than the energy the sun has put out during its entire life. This energy is what blows the outer layers of the star apart. In the expanding envelope neutrons are created that slam into other nuclei to form extremely heavy isotopes. As they decay they form elements heavier than iron. \n\nIn the core, denisty is now so great that protons and electrons can no longer exist. Instead they begin to form neutrons. When that process is complete a neutron star, about 10 to 20 km in diameter, is born. \n\nIf the mass of the star is so great that not even the neutrons can keep it from coallapsing further eventually you end up with an objects so dense its escape velocity becomes greater than the speed of light and a black hole is born.
220239
Black holes, because of their mass density, can "suck" things\ninto them but they don't do so all the time. For some reason,\nas yet unknown, black holes have periods of dormancy when\nthey stop "sucking". Quite an accomplishment for something\nthat is supposed to operate on such an elemental force as\nmass density. Black holes are also not the rare thing that\npeople would have you believe. There is one at the center\nof every galaxy that we are able to observe - including our\nown Milky Way galaxy.
5155
Because a "black hole" has a gravitational field so strong, light cannot escape.  Therefore, all we can see is that nothing is there, which appears like "blackness" to us, and since light "falls" into it, it's a "hole".\n\nThus, black hole.
430912
One theory is that every galaxy has a super-massive black hole at its center, which is slowly drawing all its stars into it. Plus the galaxies are being drawn into each other. If this continues, all matter will ultimately be drawn into one enormous black hole, which will collapse into itself and then...BANG! It starts all over again. Of course, there will be no humans around to witness it. Our star would have been destroyed long before that...
1104353
The answer to the question asked is no because black holes exist.\n\nNow then, except for black holes which are only absorbing radiation and matter, all other objects, made of atoms and molecules, present  in the universe are absorbing,reflecting and re-emitting radiation and will continue to do so as long as temperature differences/imbalances exist indicating a disequilibrium in energy distribution exists. Weak radiation activities come from changes in the electronic structures of the atoms and molecules and strong radiation activities from changes in their nuclear structures.\n\nThe second law of thermodynamics helps describe and predict the direction of all the energy exchanges taking place in the universe between objects especially the atomic/molecular objects we understand. The possibility exists however, that  --radiation may not play a part in the poorly or incompletely understood mechanics and structures of astronomical and quantum mechanical objects. TWH 06292006
508585
There have been many systems identified, some with multiple planets and a few with asteroid belts. The problem is that they are mostly discovered by measuring the minute movements of the star caused by gravitational influences of nearby orbiting objects, so most of the discoveries to date have been systems with relatively large planets (many times larger than our Jupiter) and quite close to the star so that the movement is more easily detected. Recently however, there have been more sensitive sensor arrays which have been able to resolve more "normal" configurations using sophisticated imagery, so there is hope for discoveries of systems more similar to our own in the near future. In any event, given the tremendous distances involved, the resolution of optical telescopes available in the foreseeable future would pretty much preclude any traditional photograph of such a system if it were to be found. There have been some rather blurry computer images generated from these other imaging systems, but I'd hardly call them photographs. Try monitoring <space.com>
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I only want to add that some models for non-recurring gamma ray bursts are a strong burst of radiation from an ordinary supernova relativistically beamed along some rotational axis of symmetry.\n\nIn the unlikely event such jets (about 2 degrees wide) are oriented at the Earth, the resulting gamma ray flux even from 430 ly would pretty much sterilize the side facing Betelgeuse during the second or so of the burst's duration.  Furthermore, nearly all of the ozone on that side of the planet would be destroyed, removing half of our ozone and resulting in mass extinctions on the other side too. \n\nYou can read about the supernova/GRB connection here:\nhttp://chandra.harvard.edu/press/03_releases/press_032403.html\nand here\nhttp://en.wikipedia.org/wiki/Gamma_ray_burst#GRB_Jets:__collimated_emission\n\nWhile Betelgeuse is not a probable progenitor of such an event, our current understanding of GRB sources is still highly speculative, however the association with supernova events for the short duration types is pretty strong so you can't rule it out.  Regardless, even correcting for the beaming, you expect about 1 GRB type event per galaxy per 100,000 years, so only about 1 in 1000 SN produces one.  So, making the assumption that ANY supernova has the potential to generate one of these events, the  odds that Betelgeuse is oriented properly is only 1 in 7000 and that it produces a GRB another one in 1000 for combined odds of 1 in 7 million.  Also, chances are GRBs are created by some special circumstance like very rapidly spinning stars (so you get a clear view down the axis at SN collapse) or neutron star mergers or something similarly exotic so this 1 in 7,000,000 chance about Betel doing us in is very very pessimistic.
703897
Actually, most stars are binary. Most clusters of three or more stars is a relatively short-lived (cosmologically speaking) association that usually deteriorates to binary systems. When the cluster "sheds" its extra companions, these extra companions will either pair up with another single, if sufficient gravitated to each other, or in less frequent case, remain a single star.\n\nThe size of any star is determined by several factors, such as availability and composition of the nebula from which it is formed, any other forces, or field, that may exist in the nebula, etc.\n\nThe super giant is usually the shortest-lived star. Its life span has to do with the rate of fusion within the star and that is dependent upon the surface area as opposed to the volume of the star.