In the strictest and most exact sense, there are currently 14
known black holes.
The
known closest black hole to Earth is Cygnus X-1, located about 8000
light years away.
Although
black holes have a strong suction force, they may only suck up what
crosses their event horizons, and, therefore, are not capable of
absorbing the whole universe.
In theory,
any matter can become black holes, as long as they are compressed
to zero volume and thus, yielding infinite density. However, only
the largest of stars have cores capable with the gravitational force
to compress the star to the Schwarzschild radius. Most others stars
without this gravitational force end up as neutron stars and white
dwarfs.
Although
whiteholes are mathematically possible, there have yet to be observations
to prove their existence.
Black
holes can suck up other black holes when they come in close proximity.
Usually the larger one will suck up the smaller one. Depending on
the size of the matter that is making up the black holes, the size
of the black hole created will differ. Direct collisions between
black holes are rare, as black holes are very small for their mass.
Black holes may also merge.
Black Hole Fusion
The
center of a black hole, the singularity, is the point where the
laws of physics break down. These singularities are hidden, or 'clothed'
by the black hole, so that the effects of the breakdown cannot be
observed by people outside.
At the center of a black hole, spacetime 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, thus, making it impossible to envision something
with zero volume and infinite density, such qualities of a black
hole.
By using the correct equations for motion, it can be predicted
that near a black hole, an object on a radial path will have a velocity
approaching the speed. This occurs as the object approches the event
horizon.
Stars are powered by nuclear fuel; most stars use hydrogen. The
larger a star is, the faster it will use up its fuel, and thus,
the sooner it "dies". If the stars are large enough, however,
then the gravitational pull will crush the star to 'zero volume',
or in the Schwarzschild radius. This forms a black hole.
As black holes, age, they gain more mass, as they suck in more
matter
A black hole cannot be viewed directly because light cannot escape
it. However, matter swirling around a black hole, usually gas and
dust, heats up and emits radiation that can be detected. However,
deep in the center of a supermassive black hole, stars can also
be found.
On February 1997, the Hubble Space Telescope had a new instrument
installed. Called the Space Telescope Imaging Spectrograph (STIS),
this equipment is the main black hole seeker on the telescope. A
spectrograph splits any incoming light using prisms and diffraction
gratings into a rainbow. The STIS can measure ultraviolet, visible,
and near-infrared wavelengths, allowing it to capture a wide range
of places at once. The placement and intensity of the spectrum gives
indispensable information to scientists. Every spectrum can be analyzed
to find out the speed of which stars and gas swirl at a certain
location. From this information, the mass of the object that the
stars are orbiting can be found. A massive central object is found
if the stars swirl quickly.
