Einstein believed that black holes didn't really exist. But they do: that much we know. We don't know much else about them.

Let's turn the sun into a telescope. In fact, we don't have to do any work—we just have to be in the right spot.

First, the outer boundary of these cosmic titans is a one-way light-trapping surface called an event horizon ... Einstein's 1915 theory of gravity, called general relativity, scientists can ...

April 21 is a date rich with historical significance, marked by events that have shaped cultures, nations, and the course of ...

The basic idea is that you send a beam of light around a pair of black holes spinning around each other prior to a merger, or ...

A white hole is a theoretical solution to Einstein's general relativity equations, considered the opposite of a black hole. While a black hole absorbs everything crossing its event horizon, a white ...

Einstein’s general theory of relativity, which is used to describe ... of a black hole are decoupled by a boundary called the event horizon. Because black hole gravity is so strong, anything ...

In 1949 the eminent mathematician Kurt Gödel, a longtime friend of Albert Einstein’s, discovered an exact analytical solution to Einstein’s general ... holes have an event horizon, an ...

In 1969, Penrose suggested that energy could be extracted from black holes by lowering an object into the ergosphere (the region just outside of the event horizon) and allowing it to accelerate ...

Black holes are objects whose gravity is strong enough to trap light, and the traditional black hole of general relativity is surrounded by an event horizon. Seen from outside the event horizon ...

Event Horizon Telescope ... conducted innovative simulations of spinning black holes grounded in general relativity, which clarified that the ultraluminous accretion disk (i.e., gaseous spiral ...