Dancing black hole twins spotted

Researchers have seen the best evidence yet for a pair of black holes orbiting each other within the same galaxy.

While such "binary systems" have been postulated before, none has ever been conclusively shown to exist.

The new black hole pair is dancing significantly closer than the prior best binary system candidate.

The work, published in the journal Nature, is in line with the theory of the growth of galaxies, each with a black hole at their centre.

The theory has it that as galaxies near one another, their central black holes should orbit each other until merging together.

But evidence for black holes nearing and orbiting has so far been scant.

Dancing cheek-to-cheek

As matter falls into black holes, it emits light of a characteristic colour that in turn gives information about the direction in which the black hole is moving.

In a binary system, two beams should be emitted, each a slightly different colour.


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