This is the first picture of the supermassive black hole at the heart of the Milky Way

Event Horizon Telescope Collaboration

This is the second photograph taken of a black hole, and it is close to home. The image of Sagittarius A*, the black hole at the center of our own galaxy, was released today by scientists collaborating on the massive event horizon telescope.

The same project which made quite the splash back in 2019: when they released the first image taken of a black hole. There is a black hole 55 million light-years away in the center of a giant galaxy called M87. The result helped scientists confirm Albert Einstein's theory of general relativity and verify the circular shape of these objects.

The team is back with a photo of a black hole in our own backyard. Sagittarius A*, or Sgr A*, is thought to be 4 million times the mass of the Sun. It has been inferred that it is at the center of our galaxy based on how objects move around the black hole. This is the first time we have a direct image of its dark central area. The telltale sign of the shadow of the black hole is shown in this image.

Scientists don't really know how black holes form or grow so large.

National Science Foundation/Keyi “Onyx” Li

A black hole can't be directly photographed. Black holes are so massive that nothing can escape their pull, including light. The silhouette of a black hole can be captured. If a black hole is surrounded by a swirling disc of gas and dust, the material will glow bright. The black hole's shadow is against the backdrop of gas and dust.

It's not easy to snap pictures of the black hole shadows. The size of planet Earth is needed to get the job done, according to the event horizon telescope group. Scientists came up with a way to build such an apparatus. There are radio dishes spread out across five different continents. The radio telescopes all work together to see the same object. It is up to the EHT scientists to piece together the data from the telescopes.

In order to get the M87 image, eight EHT radio dishes spent a week observing the black hole in April of last year, which resulted in months and months of work to get the data into the image. It was much more difficult to create Sagittarius A*'s image than it was to observe Sagittarius A*.

National Science Foundation/Keyi “Onyx” Li

Sgr A* is less active and dimmer than M87's black hole, making it harder to observe. The material surrounding Sgr A* has weird flaring when particles surrounding the black hole are accelerated to much higher energies. It makes for an interesting light show, but it can be hard to observe over time. The material that swirls around Sgr A* close to the event horizon moves so fast that the object appears to change in real time.

Sgr A* is in our own galaxy, which makes it harder to see from Earth. To observe the black hole, you have to look through the plane of the Milky Way. The scientists had to work around that interference.

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