What did Einstein predict about the black hole?

Einstein could be right in the end - again


Einstein is best known for his theory of relativity, but he received his only Nobel Prize for his revolutionary work on light. In classical physics, light was considered a wave, but that theory failed to explain how and why metals give off electrons when lit - a phenomenon known as the photoelectric effect.

Einstein explained the strange behavior by saying that light actually consists of individual wave packets, called photons, each with an energy corresponding to its frequency. This discovery was the spark of creation for today's quantum physics, which also states that normal atoms can behave strangely undulating - a discovery to which Einstein contributed.


Einstein's first major victory for general relativity came when he declared a mysterious additional dangling in orbit of Mercury. In 1859 the brilliant French astronomer Urbain Le Verrier traced it back to a previously undiscovered planet that pulled to Mercury and which he called "volcano". But even after years of searching, no credible evidence of Vulcan's existence could be found.

To Einstein's great enthusiasm, his new general theory of relativity brought Vulkan to his knees. It showed that the mass of the sun warps space-time in its vicinity, like a bowling ball bulges a taut trampoline. Because Mercury is so close to the Sun, its swaying orbit is the shortest path through space-time, which is curved by the Sun's mass. There was no additional planet: just a geometry in the universe that Newton could not have imagined.


During a complete solar eclipse in 1919, Einstein got right again. According to relativity, spacetime, warped by the sun's mass, should bend incoming light from stars like a lens.

British astronomer Arthur Eddington took close-up photos of the solar eclipse and discovered that the sun seemed to pull apart the Hyades, a star cluster in the constellation Taurus. The light of individual stars was bent by about a two-thousandth of a degree - in accordance with Einstein's prediction, which predicted a degree of curvature that was twice as large as calculated by Newtonian physics.

Even Einstein couldn't predict how useful this phenomenon would be for astronomers: by using galaxies like giant lenses, astronomers can look back in time, to the earliest years of the universe. And when they discover lens effects created by seemingly invisible mass, the distortions allow them to map vast fields of dark matter.