Black hole hunters look to the center of the Milky Way

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Released on October 30, 2017, this artist’s concept shows a black hole with an accretion disk.

Washington:

At the center of our spiral galaxy is a beast – a supermassive black hole with a mass 4 million times the mass of our sun and consuming every material, including gas, dust and stars that wander within its immense gravitational pull.

Scientists have used the Event Horizon Telescope (EHT), a global network of observatories working together to observe radio sources associated with black holes, to study this inhabitant of the Milky Way and announced Thursday that they have signals that they may finally image of it. The black hole is called Sagittarius A* or SgrA*.

The researchers involved in this international collaboration have declined to disclose the nature of their announcement ahead of scheduled press conferences, but issued a press release calling it a “groundbreaking achievement in the center of our galaxy.”

In 2019, the EHT team unveiled the first-ever image of a black hole https://eventhorizontelescope.org/press-release-april-10-2019-astronomers-capture-first-image-black-hole. The image — a glowing 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 also focused their work on Sagittarius A*, about 26,000 light-years – the distance light travels in a year, 9.5 trillion km – from Earth.

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

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

There are different categories of black holes. The smallest are the so-called stellar black holes, formed by the collapse of massive individual stars at the end of their life cycles. There are also medium-mass black holes, one step higher in mass. And finally, there are the supermassive black holes that inhabit the center of most galaxies. These are thought to form relatively soon after the formation of their galaxies, devouring enormous amounts of material to reach a colossal size.

The EHT project started in 2012 to try to directly observe the immediate vicinity of a black hole. The event horizon of a black hole is the point of no return above which everything – stars, planets, gas, dust and all forms of electromagnetic radiation – fade into oblivion.

The fact that black holes do not allow light to escape makes viewing them quite challenging. The project scientists have been looking for a ring of light — superheated disturbed matter and radiation that orbits 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, when viewed from above or below, the Milky Way resembles a spinning pinwheel, with our sun on 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 more massive than Sagittarius A*, which is about 54 million light-years from Earth and has a mass 6.5 billion times that of our sun. In revealing the photo of that black hole, the researchers said their work showed that Albert Einstein, the famous theoretical physicist, correctly predicted that the shadow’s shape 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. Radio astronomer Huib Jan van Langevelde, who lives in the Netherlands, is the current EHT project director.

Doeleman emphasized the size of supermassive black holes.

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

(This story was not edited by NDTV staff and was generated automatically from a syndicated feed.)



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