X-ray tagged posts

This is an X-ray image of the Perseus galaxy cluster, approximately 240 million light-years away from Earth. The x-ray radiation emitted by galaxies and galaxy clusters still poses numerous puzzles to astrophysicists. In particular, it may provide clues to the nature of the mysterious dark matter. Credit: NASA

Physicists propose a new theory of dark matter based on the detection of unusual x-ray radiation from galaxies. It implies that dark matter particles may be very different from what is normally assumed. In particular, their theory involves dark matter particles which are extremely light – almost 100X lighter than electrons, in stark contrast to many conventional models that involve very heavy dark matter particles instead.

According to common theory, dark matter must exist because ot...