Russia Today 
Saturday, Nov 22, 2008
Scientists think they may have discovered an elusive substance known as dark matter – which experts believe makes up 90 percent of the universe. It’s hoped it may hold the key to how and when the universe was formed.
The breakthrough was made by a high tech system above Antarctica which detected that a nearby object is pounding the earth with particles. The authors of the new study, the ‘Advanced Thin Ionization Calorimeter’ (ATIC), believe that it could be one of two cases.
“In the first case, we have now seen for the first time a nearby source of cosmic rays. Nobody’s seen that before,” said study co-author John Wefel, a physicist at Louisiana State University.
However, as remarkable as that is, scientists are hoping that it could be long awaited proof of the existence of dark matter.
(ARTICLE CONTINUES BELOW)
The term ‘nearby’ is used in a relative sense, meaning less than 3000 light years from earth. How long, you may ask, is a light year? The correct question is ‘how far is a light year?’ A light year measures distance. Light travels at 300,000 km/second.
One light year is 9,460,730,472,580.8 km which gives us an idea (or just confuses us) about the size of the universe itself. There are some stars in the universe that are over one billion light years away!
Back to the dark stuff
Dark matter, along with dark energy, are said to form most of the mass in the universe, yet it has been virtually undetectable. The matter has some very interesting properties which are what give scientists reasons to believe it exists.
Perhaps one of the most remarkable is its ability to act as a lense. Gravitational lensing, as it is known, causes light from a background source to be refracted and bent around a large object blocking it’s path.
From earth we are able to observe galaxies and stars that are hidden behind massive galaxies due to this effect. In simpler terms, if two people are standing on opposite sides of a large wall, there is no way, without the help of a mirror, that both people can see each other.
However, in space, the dark matter would allow for the image of one person to be bent around the wall so that the person on the other side could see him.
Scientists are hoping that with the further success of the current experiment, and other projects like the particle collider in Switzerland, will soon answer the most fundamental question of our existence.
But for now, there is no need to worry, dark matter will not harm you.