Einstein was right! Black hole image confirms general theory of relativity

When matter approaches a black hole's event horizon - the point at which not even light can escape - it forms an orbiting disk.

Black holes are long-time superstars of science fiction. But their Hollywood fame is a little strange given that no-one has ever actually seen one – at least, until now. If you needed to see to believe, then thank the Event Horizon Telescope (EHT), which has just produced the first ever direct image of a black hole. This amazing feat required global collaboration to turn the Earth into one giant telescope and image an object thousands of trillions of kilometres away.

As stunning and ground-breaking as it is, the EHT project is not just about taking on a challenge. It’s an unprecedented test of whether Einstein’s ideas about the very nature of space and time hold up in extreme circumstances, and looks closer than ever before at the role of black holes in the universe.

ALSO READ: First ever images of black hole: How this landmark achievement came about

To cut a long story short: Einstein was right.

Capturing the uncapturable

A black hole is a region of space whose mass is so large and dense that not even light can escape its gravitational attraction. Against the black backdrop of the inky beyond, capturing one is a near impossible task. But thanks to Stephen Hawking’s groundbreaking work, we know that the colossal masses are not just black abysses. Not only are they able to emit huge jets of plasma, but their immense gravity pulls in streams of matter into its core.

When matter approaches a black hole’s event horizon – the point at which not even light can escape – it forms an orbiting disk. Matter in this disk will convert some of its energy to friction as it rubs against other particles of matter. This warms up the disk, just as we warm our hands on a cold day by rubbing them together. The closer the matter, the greater the friction. Matter closer to the event horizon glows brilliantly bright with the heat of hundreds of Suns. It is this light that the EHT detected, along with the “silhouette” of the black hole.

Producing the image and analysing such data is an amazingly hard task. As an astronomer who studies black holes in far away galaxies, I cannot usually even image a single star in those galaxies clearly, let alone see the black hole at their centres.

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