Dark Matter Introduction
In cosmology, dark matter has matter particles that cannot be spotted by their releases of radiation but when they are there, they can be taken from gravitational effects on visible matter such as stars and galaxies. The speed of these particles is crucial to the Big Bang model of cosmology and the order of formation of the Universe's great structures. (Dark Matter Physics. (2006)). The galaxy is spinning so fast, that the stars could fly away way out of the universe. Scientist have found out that it is dark matter and energy, that is holding the stars and everything in place. (Hawkins, S. (1980))
Scientists have no evedence if Dark Matter gives off any kind of electromagnetic energy. (Black Matter. (2001)). Galaxies probably developed from huge clumps of matter billions of years ago. (Black Matter. (2001)). Possibilities for dark matter range from tiny subatomic particles weighing 100,000 times less than an electron to black holes with masses millions of times that of the sun. (Cosmic Hide and Seek. (1995)). Most dark matter is located within galaxies. (Dark Matter Physics. (2006)), it estimates of the amount of matter in the galaxies, based on gravitational effects, every time it suggests that there is far more matter than is what you see. (Dark Matter (2007)) Dark matter, is basically the things that keeps the space in form. If there was no dark matter, everything from space would just fly everywhere, and disappear.
Dark Matter is invisible matter that is believed to make up 99 percent of mass of the Universe. It may be in the form of Black Holes, or possibly exotic particles (Couper, H & Herbest N. (1996)). The dark matter component has much more mass than the things that you can see of the universe. (Wikipedia. (2007)) Astronomers are not sure what dark matter includes, but they think it have MACHO, and the WIMPS (Wikipedia (2007)) Most dark matter is located within galaxies. (Dark Matter Physics. (2006)) On a galaxy scale, the dark matter rate would be up to 10 times that of the luminous matter. (Dark Matter Physics. (2006))
The background of the galaxy and the universe can only be the same if the average density of the universe and the rate of expansion are the same everywhere. The fate of the universe depends crucially on how matter it contains (matter determins the gravity of the universe, to little gravity, there will no be enough to exert the gravitational pull of the universe. The universe will crunch together and cause an explosian). (Couper, H & Herbest N. (1996))
Types of Dark Matter
There are two kinds of dark matter. There is cold dark matter and hot dark matter. Hot dark matter is composed of particles that have zero or near-zero mass, and cold dark matter is composed of objects sufficiently massive that they move at sub-relativistic velocities (Dark Matter. (2004)). If the cold dark matter is the main component of the Universe, the particles will go on a smaller distance and thus will erase the density's fluctuations on extents smaller than in the case of hot dark matter (Dark Matter Physics. (2006))
There is five times more material in clusters of galaxies than we would expect from the galaxies and hot gas we can see. (NASA. (1997-2007)). The motion of stars around the centers of their galaxies says there should be about 90% of the matter in a typical galaxy is dark. Physicists think that there is also dark matter between the galaxies but this is harder to know for sure.
WIMPS & MACHO
Scientists are not that sure of what dark matter consists of, but they think it is the MACHO, and the WIMPS (Wikipedia. (2007)). Some of Dark Matter may consist of massive astro-physical compact halo objects (MACHO's), large bodies made of ordinary matter. (Black Matter. (2001)). Some particles that move much slower then light are called weakly interacting massive particles (WIMP's). (Black Matter. (2001)).
Aside from WIMPS, most dark matter may consist of massive astro-physical compact halo objects (MACHO's), large bodies made of ordinary matter (Black Matter. (2001)). If a MACHO were to pass in front of a star in a nearby galaxy, the gravitational feild would bend the star light. This bending would brighten the stars image temporarily. (Black Matter. (2001)). The MACHO bends the light waves because of the gravitational pull of the mass of itself. Scientists believe that it also makes the starlight brighter because of the way the MACHO bends the light. The gravity of the MACHO bends the light towards the other rays of starlight, from a far distance you can see both of the rays fused together which gives off double the brightness.
Black Holes
A black hole is an object predicted by the theory of general relativity. (Black Hole, Wikipedia) Gravitational pull so strong light cannot escape. (Black Hole, Wikipedia) A region in the space-time "fabric" where escape to the outer universe is impossible. (Black Hole, Wikipedia) Outer boundary called the event horizon. (Black Hole, Wikipedia) Nothing can escape once in the region of the event horizon. (Black Hole, Wikipedia) Once inside event horizon, no longer seen for no light can escape the pull of gravity (Black Hole, Wikipedia) The inside of a black hole is called Singularity (Black Hole, Wikipedia) Singularity is a place where matter is compressed so hard, that laws of physics no longer exist because compression so hard. (Black Hole, Wikipedia) Black holes can theoretically be of any size. They can go from as little as a star, to as big as a humongous planet. (Black Hole, Wikipedia) Also, it has been stated that it may leak out some energy. (Black Hole, Wikipedia) This energy called Hawking Radiation. (Black Hole, Wikipedia) Anything on its path to this singularity will also collapse on its way to the black hole, such as matter, energy, and even light the fastest thing available in the universe. (Black Hole, Wikipedia) Black Holes are also the darkest things in the Universe, so it is hard to see one. (Couper, H., & Henbest, N. 1996) A Black hole is a concentration of mass so great, that gravity prevents anything from escaping it. (Black Hole, Wikipedia) The gravitational field around it is so strong that the escape velocity around it exceeds the speed of light. (Black Hole, Wikipedia) Therefore, nothing, not even light, can escape its gravity. (Black Hole, Wikipedia) A black hole is formed when a star dies and the remains of the star become a black hole. (Ferguson, K. 1991)
