This year, NASA's Chandra X-ray Observatory celebrates its own "sweet 16."

A fast-moving pulsar appears to have punched a hole in a disk of gas around its companion star and launched a fragment of the disk outward at a speed of about 4 million miles per hour.

While fireworks only last a short time here on Earth, a bundle of cosmic sparklers in a nearby cluster of stars will be going off for a very long time.

Galaxy groups are families of galaxies that are bound together by gravity. They are very similar to their larger cousins, galaxy clusters.

While scientists and philosophers have tried to figure out exactly what light is for millennia, it's only been in the past several hundred years or so that we've really started to figure it out.

These rings are light echoes, similar to sound echoes that we may experience here on Earth.

The year 2015 has been declared to be the International Year of Light and Light-based Technologies by the United Nations.

Since space-time foam, as it is called, is so tiny, scientists cannot observe it directly.

Chandra does not look at light that we can see with our eyes. It detects x-rays from the Universe.

A new study reveals that the X-ray output from SGR 1745-2900 is dropping more slowly than for other magnetars, and its surface is hotter than expected.