Technofender

Dark matter is and has been an elusive topic in Astronomy and Physics for the last seven decades. It has gravity but does not interact in any other usual way with the "normal" matter which composes the gases, stars and people.

Dark matter has always been evidenced indirectly, as many scientists and their calculations point to the fact that there is not enough normal matter in the galaxies to justify their gravity. It seems as if dark matter is composed of a specially elusive particle that interacts with normal matter only by affecting its gravity.

But, recent discoveries on the few stars inside some small galaxies - dwarf galaxies - around the fringes of the Milky Way, point to them as dark matter distilleries - 1000 times more dark matter than normal one.

Plans for the future include the use of the Large Haldron Collider - the best and most powerful particle accelerator ever built - of CERN to produce dark matter particles. The Collider is scheduled to start working next year.

Discovery of Dark Matter Dense - Dwarf Galaxies

Marla Geha and Josh Simon worked with the Telescope at Keck Observatory, Hawaii, gathering light from 814 stars in eight dwarf galaxies, and split the light into spectra.

As you may possibly know, the speed at which the star moves changes the way it’s transmitted, that’s a measurable effect. Analyzing the spectra is always possible to know the speed at which the light source - the star - is moving.

Susprisingly, the team found that the stars were heavily slow movers - snail stars. Compared to the 220 Km/s of the Sun, these stars moving at 4-7 Km/s were extremely slow. The reason, as suggested by the team is the abnormal concentration of dark matter that opposes the movement of the stars.

Census of Dwarf

Finding the dwarf galaxies is not an easy task, and certainly might seem like looking for a needle in a haystacks, as the Principal of the Observatory suggests. It’s needed a surveyor capable of looking at vast spaces and identifying very subtle differences in patterns of stars. Then, you need a high quality telescope with spectroscope to analyze the light from the stars.

Bullock & Johnston, syndicated from the Discovery News.

Dark Matter Distilleries
A simulated image of stars distributed around our galaxy, the Milky Way. The bright point-like objects are dwarf galaxies like those recently discovered.

What makes it more difficult is that these galaxies have little stars due to the higher concentration of dark matter compared to the normal one.

Genesis of Dwarf Galaxies

There are two theories according to Dr. James Bullock of the University of California at Irvine. First, they were normal galaxies made of normal and dark matter, with lots of stars that were "dead" and its normal matter escaped away. The second theory is that they were always full of dark matter and short of the normal one, so, they never had the chance to produce many stars.

One interesting pick is that all these galaxies HAVE EXACTLY THE SAME MASS. That and many other misteries still to be unveiled, will surely explain a lot about the origin of the galaxies - in general.

Via: Discovery News