While solitary black holes should be common, they are hard to find. The one in Sagittarius revealed itself when it passed in front of a dim background star, magnifying the star’s light and slowly ...

"We've always known that we need something to complete the puzzle, but we haven't really known what shape or form those ...

In a baffling cosmic mystery, astronomers have reported a star that appeared to vanish without a trace. One night it was there, shining bright—and the next, it was gone. No explosion, no fading, no ...