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| Stuck in a Black Hole? |
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| Frequently Asked Questions |
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11)
Where are the best candidates for black holes located? --------------------------------------------------------------------------------- 11) Where are the best candidates for black holes located? Astronomers
distinguish between two classes of black holes-stellar mass and
supermassive. Stellar-mass black holes have masses from about 1
to 10 times the mass of the Sun and are the end products of the
evolution of very massive stars. These are often found in binary
star systems where they can be most easily detected as they affect
the nearby star. Supermassive black holes contain millions or even
billions of times the mass of the Sun and are found in the nuclei
of galaxies and quasars, which the Hubble Space Telescope has confirmed
in images, such as Plate 8, which shows the inner core of the quasar-like
galaxy Messier 87 in the constellation Virgo. Table 10 is a list
of the current suspected and confirmed black holes. 12) Does the matter that falls into a black hole come out as another big bang? We will never know, because we can never look inside a black hole to see what is going on, and we can never look behind it to see what comes out in some other dimension or universe. Because there is no experiment we can conduct to test this hypothesis, it is not a scientifically interesting question, no matter how compelling it seems. 13) Do tidal gravitational forces near a black hole singularity distort the shapes of fundamental particles? Inside a black hole is a region called the singularity where the curvature of space-time becomes infinite according to Einstein's general relativity. Other than theoretically, no one really knows what happens close to a singularity, but, in what is called a quantum gravity theory, no singularities actually exist. This extreme condition in space is simply replaced by a region where the graininess of space and time becomes evident at the so-called Planck scale. Because all fundamental particles are believed to be some kind of loops of energy, also about the size of the Planck scale, 10-33 centimetres, individual particles just dissolve away into some kind of quantum froth at these scales. But we do not know for sure and have absolutely no way of finding out. 14) Is there really a black hole in the centre of the Milky Way? Yes. The data in hand seem to indicate very clearly that a very dense point mass containing several million times the mass of the Sun is located in the core of the Milky Way. The only logical candidate is a black hole, because an equivalent number of normal stars crowded together into a solar system-sized volume of space would look very different than what we actually seem to be detecting in the core of the Milky Way in an object astronomers call Sagittarius A*. 15) Is it true that there is a huge black hole that has swallowed thousands of planets. It is sure that this has happened in some distant galactic core containing a supermassive black hole, although, of course, we cannot know of a particular example where this has actually happened. Supermassive black holes, like the one in Messier 87 (Plate 8), do, however, swallow stars and gas, and it is not a big stretch of the imagination that some of these stars were accompanied by planetary systems. What a dreadful fate. To be able to look up at the sky and see a distant hole in space, knowing that in a few centuries you and your world would cease to exist, and there is not a single thing you could do about it. The laws of physics are cruel, and they can destroy worlds as easily as the fool who steps out a window on the forty-fifth floor. But to see your civilization's destiny literally written in the stars each night in this slow-motion death dance that lasts for decades must be simply awful. |