First picture of our galaxy’s supermassive black hole revealed

By Leah Crane.

Scientists took a picture of the black hole at the center of the universe. This is the second image of a black hole.

The image was captured by the EHT, a network of observatories around the world that operate as a single enormous radio telescope. The Sagittarius A* or Sgr A* black hole is located in the centre of the M87 galaxy, while the M87* black hole is located in the center of the Milky Way. The picture of Sgr A* was finally released after three years of data analysis, after the image of M87* was released in 2019.

Ziri Younsi is a researcher at University College London.

Black holes don't emit light, so the image shows the black hole's silhouette against a glowing background of hot plasma being pulled into Sagittarius A*.

The new image took so long to produce because it took more time with this black hole. One of the largest known black holes in the universe is called M87* and it has a mass 1000 times that of the sun. The time it takes for the hot plasma to circle Sgr A* is only minutes.

It was like trying to take a clear picture of a puppy chasing its tail as the EHT collaboration was observing the gas around Sgr A*.

The researchers had to deal with light from all the stars, dust and gas between our planet and Sgr A* because Earth sits towards the edge of the Milky Way. To make the final image, they aggregated many snapshots taken over the course of several nights and used a supercomputer to process the data.

Younsi says that everyone was cautious this time, because it was a much harder image to make.

There are two completely different types of galaxies and two very different black hole mass, but close to the edge of these black.

Not even beams of light can escape from a black hole that is so strong.

The ring of light around the black hole is predicted to be a little tilted. The light bends due to the strong pull of Sgr A*, which makes the plasma circling towards us appear brighter than the black hole's backside.

The image of Sgr A* was compared to a library of hundreds of thousands of simulations of black holes that do not follow general relativity.

As researchers continue to analyse the black hole data and figure out how the two black holes compare to one another, they also have a new set of observations to examine. Before the most recent observing campaign in March 2022, three telescopes were added to the EHT network, which means future pictures should be sharper and illuminate subtle details in the areas around black holes. The team is making a video showing how Sgr A* changes over time.

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