Dark Matter

Scientists have detected an unexplained source of positrons in space after using a space based research satellite called Pamela ( Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics), launched in June 2006.

This satellite carries instruments designed to investigate Dark Matter particles in space. It has detected an excess of positrons in an area where scientists expected to see fewer.

Recording the ratio of positrons (anti-particles of electrons with a positive charge) to electrons, the instruments found a high ratio of positrons with a high energy level.

Under normal circumstances (or at least as far as we understand anyway) the ratio of positrons to electrons should decrease with an increase in energy and so to find this with increasing energy instead is not expected.

Dark Matter is at the moment purely hypothetical matter so far undetectable by its emitted radiation. It's presence is inferred by gravitational effects on visible matter and it is the current theory to explain why there is a large amount of "missing mass" in the universe.

According to current observations Dark Matter and Dark Energy account for the vast majority of mass in the observable universe. Of the total mass in the universe, 22% is supposed to form Dark Matter, 74% Dark Energy and the remaining 4% visible energy and matter.

There could however be other explinations for this, one other explination would be the particles could be coming from a pulsar (a rapidly rotating super dense dead star that releases loads of energy) and this would be the simplest (and easiest) solution.