Black Hole Startling Facts, Questions and Answers.

What’s the point in trying to impress people with things about cooking, football, weather and the things that your mum or dad knows? Why not impress people with facts on black holes instead? You may even put them to sleep. Here’s a few interesting facts on black holes-

• When material falls into black hole, a process called accretion, usually about 10% of the energy gets radiated away as the material approaches the black hole. The other 90% gets absorbed into the black hole and simply adds to its mass. In some cases, the material won’t have a chance to radiate much energy and essentially all of the mass goes right into the black hole. Quasars may represent instances where black holes have swallowed significant fractions of entire galaxies – billions of solar masses!

Quasar

• Black holes don’t fill up because it is already essentially a geometric point, with effectively infinite density. There is no limit to the mass of a black hole. There is a region around black holes called the event horizon. Once anything, including light, crosses the event horizon, it can never escape. This is what gives the black hole its name. The size of the event horizon gets bigger as the black hole gets more massive. This allows the black hole to “grow”, in a sense, as more mass falls in.
• Life doesn’t survive in a black hole because anything that falls into a black hole will get heated to very high temperatures. Also, once the material gets very close to the black hole, tidal forces will stretch it very thin (just think about the effect that a Moon has on the Earth’s oceans, and a typical black hole is likely to be much more massive than the Moon).
• At the centre of a black hole the singularity point has zero volume, space-time has infinite curvature and matter is crushed to infinite density under the pull of infinite gravity.  At a singularity, space and time cease to exist as we know them. The laws of physics as we know them break down at a singularity, so it’s not really possible to imagine something with infinite density and zero volume.
• All the matter in the universe will not end up in black holes. Most stars in the universe don’t have enough mass to become black holes at the end of their lives. Neutron stars and white dwarfs are much more numerous; this is what most stars end up as. Black holes are not cosmic vacuum cleaners, they will not suck up everything in the universe, and they only suck up what crosses their event horizons.

the neutron star

• How many black holes are there? Scientists generally agree when the compact object in an X-ray binary system is shown to be more massive than about 3 times the mass of the Sun, then this compact object is a black hole beyond reasonable doubt. These are called dynamically confirmed black holes. 20 have been confirmed. Another definition of a black hole gives many more.

black holes

• The nearest black hole is believed to be a nearby object and is observed by observations of strong X-ray emissions from Cygnus X-1, located about 8000 light years away. But this all depends on the definition that you use to find your black hole. Another lies just 1,600 light-years from Earth on the way to the centre of the Milky Way in the direction of the constellation Sagittarius and is associated with a visible star called V 4641. It is being called a micro-quasar because it showed the brilliant behaviour associated with quasars. It sends out bursts of X-ray radiation and shoots out jets of plasma at some 90 percent the speed of light.

cygnus x-1

• White holes have been talked about but are very hypothetical. They are supposed to be what comes out from the other side of a black hole and where all the mass that goes into the black hole goes to. As I have already said a black hole tends to get bigger as more mass goes in, so really mass just gets added to the black hole and there is no real need for a white hole. If White holes did exist (and there’s nothing saying they don’t) then they could be a connection to a parallel universe or a distant region of space perhaps in the future or the past. Mathematics does say that black holes and white holes could exist but they would only probably exist for a very short period of time. So don’t hang around too long in your shiny spaceship.
• Black holes are powerful so why not use them as a power source? Their own power is really their downfall in this case, how do you control it? How do you move it where you want it to go and produce power? Once it’s in the place that you wanted how do you actually keep it there? This has actually been studied believe it or not. A process called the Penrose process has been suggested. Hawking radiation actually gives off photons evaporating from the black hole and this could be used as an energy source if you had the means to transport it (and that would be a very long way if you used a cable from the nearest black hole).

Black holes bring up many questions but not really any answers that can be proved. It is still great to wonder and think about them and hopefully come up with more questions without answers. One day I expect, not in the very close future, answers will be forthcoming and a trip to a black hole might be in the travel agents window.