Black hole hunters peer into the center of the Milky Way

WASHINGTON, May 10 (Reuters) – Residing at the center of our spiral galaxy, the Milky Way, is a beast: a supermassive black hole that is 4 million times the mass of our sun and consumes any material, including gas, dust, and stars drifting within it. huge gravitational pull.

Scientists have been using the Event Horizon Telescope (EHT), a global network of observatories that collectively work to observe radio sources associated with black holes, to study this inhabitant of the Milky Way and have set an announcement for Thursday stating they may have finally gotten a picture. from that The black hole is called Sagittarius A* or SgrA*.

The researchers involved in this international collaboration declined to reveal the nature of their announcement ahead of scheduled press conferences, but did issue a press release calling it a “groundbreaking result at the center of our galaxy.”

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In 2019, the EHT team revealed the first photo of a black hole. The image, a bright ring of red, yellow and white surrounding a dark center, showed the supermassive black hole at the center of another galaxy called Messier 87 or M87.

The researchers have also focused their work on Sagittarius A*, located about 26,000 light-years, the distance light travels in one year, 5.9 billion miles (9.5 billion kilometers), from Earth.

“One of the objects that we hope to observe with the Event Horizon Telescope … is our own black hole in our own backyard,” said Harvard-Smithsonian Center for Astrophysics astrophysicist Sheperd Doeleman, former director of the EHT project, during a meeting of July 2021. scientific presentation.

Black holes are extraordinarily dense objects with gravity so powerful that not even light can escape.

There are different categories of black holes. The smallest are so-called stellar-mass black holes formed by the collapse of massive single stars at the end of their life cycles. There are also intermediate-mass black holes, a step up in mass. And finally there are the supermassive black holes that inhabit the center of most galaxies. They are thought to arise relatively soon after their galaxies form, gobbling up huge amounts of material to reach colossal size.

The EHT project was started in 2012 to try to directly observe the immediate environment of a black hole. A black hole’s event horizon is the point of no return beyond which anything – stars, planets, gas, dust, and all forms of electromagnetic radiation – is sucked into oblivion.

The fact that black holes don’t let light escape makes seeing them quite a challenge. Project scientists have searched for a ring of light (disintegrated superheated matter and radiation circulating at tremendous speed at the edge of the event horizon) around a region of darkness that represents the actual black hole. This is known as the shadow or silhouette of the black hole.

Known as a spiral galaxy, the Milky Way viewed from above or below resembles a spinning pinwheel, with our sun in one of the spiral arms and Sagittarius A* in the center. The galaxy contains at least 100 billion stars.

The black hole M87 is much more distant and massive than Sagittarius A*, located about 54 million light-years from Earth with a mass 6.5 billion times that of our sun. Revealing the photo of that black hole, the researchers said their work showed that Albert Einstein, the famous theoretical physicist, had correctly predicted that the shape of the shadow would be almost a perfect circle.

Thursday’s announcement will be made at simultaneous press conferences in the United States, Germany, China, Mexico, Chile, Japan and Taiwan. Netherlands-based radio astronomer Huib Jan van Langevelde is the current director of the EHT project.

Doeleman emphasized the size scale of supermassive black holes.

“There are big things out there and we are small,” Doeleman said. “But that’s also kind of uplifting in a way. We have a lot to explore in the universe.”

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Reporting by Will Dunham, Editing by Rosalba O’Brien

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