The universe may include a huge number of galaxies that have very few stars. They consist of dark matter. Ultimately these galaxies can be much more than ordinary galaxies with bright stars and gas, and the ratio between them can be 100 to 1. This prediction was made by the astronomers Neil Trentham, Ole Moller and Enrico Ramirez-Ruiz of the University of Cambridge. Their paper will be published in Monthly Notices of the Royal Astronomical Society.

There are already plenty of evidence that bright galaxies contain a large amount of dark matter, the mass of which is often ten times the mass of all the stars in the galaxy. In order to explain the observed movement of the stars under the influence of gravity of the entire galaxy, there must be additional mass that we do not see. In some galaxies that are available observations of stars is clear that they were capable of making the galaxy and to exist as a galaxy.

The theory predicts that one massive galaxy has a lot of galaxies with low mass, which we cannot see. This is because they have very few or no stars. Thus the question arises: how to find these dark galaxy?

It is a difficult task, and the search technique will depend on the nature of dark matter, which is still unknown. If dark matter consists entirely of elementary particles, the dark galaxies can act as a gravitational lens, deforming the appearance of distant galaxies lying behind them. If the dark galaxy will include brown dwarfs, their infrared radiation can be detected. Watchable and proanalizirovana stars such as white dwarfs or black holes. If these objects were on a small distance from us, it would be possible to detect these extinct stars, playing the role of gravitational lenses for radiation individual stars in other galaxies out of the dark galaxy. Several of these effects on the small area of the sky could mean the presence in this direction dark galaxy.

Researchers have identified one of those places where it can be dark galaxy. Galaxy UGC 10214, of which explicitly outflow of matter as if she would interact with another galaxy. But this galaxy is not visible, and the flow of the material flows as though nowhere.