NewslettersSign inAPP
españaESPAÑAargentinaARGENTINAchileCHILEcolombiaCOLOMBIAusaUSAméxicoMÉXICOperúPERÚusa latinoUSA LATINOaméricaAMÉRICA

LATEST NEWS

Supermassive black hole: first image of Sagittarius A* revealed

A worldwide network of scientists known as the Event Horizon Telescope Collaboration has released the first ever image of the supermassive black hole at the centre of our galaxy.

Update:
A worldwide network of scientists known as the Event Horizon Collaboration has released the first ever image of the supermassive black hole at the centre of our galaxy.
EHT COLLABORATION/NATIONAL SCIENVIA REUTERS

Astronomers have produced the first ever image of Sagittarius A*, the supermassive black hole long thought to exist at the centre of the Milky Way, our home galaxy. The historic image of the black hole, known for short as Sgr A*, was released on Thursday by the Event Horizon Telescope (EHT) Collaboration, a global network of scientists comprising over 300 researchers and 80 institutes.

The EHT Collaboration used an array of telescopes around the world to create a virtual ‘Earth-sized’ telescope, whose name, Event Horizon, refers to the entrance to a black hole. The EHT combined data collected at each location to produce an image that is the average of thousands of images taken of Sgr A*.

How far away is Sgr A*? How big is it?

Located about 27,000 light years away from Earth, Sgr A* has a mass four million times that of our Sun and has a diameter of around 60 million kilometres - about a third of the distance between Earth and the Sun. While we cannot see the black hole itself, the image released on Thursday offers up a “telltale signature” pointing to its presence, the EHT Collaboration said in a statement: “a dark central region (called a ‘shadow’) surrounded by a bright ring-like structure”.

What exactly is a black hole?

A black hole is an area in space where gravity is so strong that nothing can escape from it - not even light, which travels faster than anything else in our universe. Because light cannot be released from inside a black hole, it is impossible to see beyond the threshold to a black hole without entering it yourself. That’s why the boundary is known as the event horizon.

While scientists have established a firm understanding of how low-mass black holes are formed - essentially, this occurs when a star collapses in on itself - it remains less clear how supermassive black holes such as Sgr A* are formed.

“Overwhelming evidence the object is indeed a black hole”

Experts have believed for decades that there is a black hole at the centre of the Milky Way, but this is the first visual proof to back this up. “This result provides overwhelming evidence that the object is indeed a black hole and yields valuable clues about the workings of such giants, which are thought to reside at the centre of most galaxies,” the EHT Collaboration said.

Sgr A* is the second black hole the team has successfully pictured. In April 2019, the EHT Collaboration released the first ever image of a black hole: M87*, located at the centre of the Messier 87 galaxy, some 55 million light years from Earth. More than a thousand times bigger and more massive than Sgr A*, M87* actually proved easier to capture, despite being far further away.

“Like taking a clear picture of a puppy chasing its tail”

“The gas in the vicinity of the black holes moves at the same speed - nearly as fast as light - around both Sgr A* and M87*,” EHT scientist Chi-kawn Chan explained. “But where gas takes days to weeks to orbit the larger M87*, in the much smaller Sgr A* it completes an orbit in mere minutes. This means the brightness and pattern of the gas around Sgr A* was changing rapidly as the EHT Collaboration was observing it - a bit like trying to take a clear picture of a puppy quickly chasing its tail.”

The EHT Collaboration’s findings are to be published on Thursday in a special issue of The Astrophysical Journal Letters.

Rules

To be able to comment you must be registered and logged in. Forgot password?