What object did the Event Horizon Telescope first image in 2019?

The Event Horizon Telescope first imaged the M87* black hole in 2019.

The image, released on 10 April 2019, showed a bright ring of hot gas surrounding a dark central region, or shadow, associated with the supermassive black hole at the centre of the galaxy Messier 87. M87* lies about 55 million light-years from Earth and has a mass estimated at roughly 6.5 billion Suns.

The Event Horizon Telescope is not one conventional telescope. It is a global network of radio observatories that used very-long-baseline interferometry to act like an Earth-sized virtual telescope. Researchers combined observations collected in April 2017 and processed an enormous volume of data to reconstruct the image.

The result was the first direct visual evidence of a black hole’s shadow and strongly supported predictions from general relativity. Sagittarius A*, the supermassive black hole at the centre of our own Milky Way, was imaged later, in 2022. The two images are often confused because both objects are central targets of black-hole research.