Black hole confirmed: Scientists have revealed the first image of Sagittarius A*

The supermassive black hole at the center of the Milky Way.
Chris Young
The first image of Sagittarius A*ESO/YouTube

For years scientists have known that the Earth orbits the Sun, and the Sun slowly orbits our galaxy's — the Milky Way's — mysterious center.

What lies at the heart of the Milky Way has only been theorized and inferred by measuring its gravitational impact on its surroundings in space, until today.

Now, scientists from the Event Horizon Telescope (EHT) team have revealed the first-ever image of the supermassive black hole, Sagittarius A* (pictured above), at the heart of our galaxy.

The first-ever image of Sagittarius A*

Today's historic announcement marks the first time the wider public sees an image of Sgr A*, providing "overwhelming evidence that the object is indeed a black hole," EHT wrote in a statement. 

The new image also "yields valuable clues about the workings of such giants".

The EHT team announced the reveal event days ago. The last time they teased a reveal with such fanfare, the organization unveiled the first-ever image of a black hole, showing the world a picture of the black hole M87*.

Now, aside from finally providing photographic evidence that Sgr A* exists, the new image also provides evidence for the theory that the supermassive black hole at the Milky Way's center is spinning. It also allowed the EHT scientists to determine Sgr A*'s orientation relative to Earth, showing that it is facing us.

More than 300 international scientists, support personnel, and eight radio observatories worldwide worked in collaboration to achieve the groundbreaking result. Their findings were published today in a special issue of The Astrophysical Journal Letters.

During a press conference held by the Earth Science Observatory, Dr. Jose L. Gómez, a research scientist at the Instituto de Astrofísica de Andalucía (CSIC), said imaging Sgr A* was significantly more challenging than imaging M87*, which is over one thousand times larger.

It was "like trying to take a clear picture of a running child at night," Gómez explained.

Capturing Sgr A* with an "Earth-sized camera"

The EHT team revealed that tens of millions of images taken by its worldwide network of radio telescopes were combined to provide the final image that has today been shared with the world.

Though Sgr A* is closer to Earth than M87*, the fact it is significantly smaller means the gas surrounding the black hole rotates at a much faster speed, which resulted in a blurrier image than the one revealed in 2019 of M87*. Still, it's worth pointing out that the EHT can see 3 million times sharper than the human eye and that Sgr A*, which is about 27,000 light-years from Earth, has a mass 4 million times greater than that of our Sun.

The EHT is made up of a global network of synchronized radio observatories that work together to observe radio sources, allowing them to image the event horizons of black holes. Several of the scientists at today's press briefing referred to the EHT as an "Earth-sized camera".

They also referred to their new image in relation to Einstein's Theory of General Relativity, which first identified the concept of a black hole. "We were stunned by how well the size of the ring agreed with predictions from Einstein's Theory of General Relativity," said EHT Project Scientist Geoffrey Bower from the Institute of Astronomy and Astrophysics, Academia Sinica, Taipei. "These unprecedented observations have greatly improved our understanding of what happens at the very center of our galaxy and offer new insights on how these giant black holes interact with their surroundings."

The EHT team now wants to "make movies" of black holes

Before the EHT captured its image evidence of Sgr A*, the scientific community had only inferred the existence of the supermassive black hole by measuring its gravitational effect on surrounding objects.

Following their groundbreaking new investigation revealing the heart of the Milky Way, the global EHT team wants to provide more images and even videos of other black holes. "We now want to go on and make movies [of black holes]," J Anton Zensus, Director at the Max Planck Institute for Radio Astronomy, said during the press announcement event.

The team has already provided us with a new perspective on the cosmos — proving Einstein's theories in the process — and it only means to continue on the same path.

This was a breaking news story, and it was updated regularly as more information emerged. The Earth Science Observatory press conference can be watched as it happened below.

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