That there is a headline I never expected to write. No, really. Even just “sterile neutrinos” had escaped all my prior prognostications. Anyway:

Mysterious X-ray Signal Intrigues Astronomers

A spike in X-Rays from the Perseus cluster of galaxies (240 million light years away, containing thousands of galaxies, one of the most massive structures in the known universe) has been interpreted by at least a few scientists as *possibly* being due to the decay of “sterile neutrinos” which only interact with regular matter via gravity. These would potentially be part of the mysterious realm of dark matter.

Additionally: the Perseus cluster was the source of the deepest tone ever detected. Most wavelengths people ever hear about, whether the wavelengths of light or sound, have oscillation periods measured in thousandths or millionths of a second. But radio waves emitted as the result of the relativistic expansion of plasma bubbles in the core of one of the clusters galaxies have an oscillation period of 9.6 million *years.*

The universe is a durned nifty place.