NuSTAR observations of the Cassiopeia A supernova remnant reveal sites of dramatic cosmic ray acceleration.

The earliest NuSTAR observations of a supernova reveal the turbulent final years of a star's life.

What remains of the star that exploded just outside our galaxy in 1987? Debris has obscured scientists’ view, but two of NASA’s X-ray telescopes have revealed new clues.

A brief and unusual flash spotted in the night sky on June 16, 2018, puzzled astronomers and astrophysicists across the globe. The event - called AT2018cow and nicknamed "the Cow" after the coincidental final letters in its official name - is unlike any celestial outburst ever seen before, prompting multiple theories about its source.