The first image of Sagittarius A* has been revealed at the center of the Milky Way

The black hole is about 27,000 light-years away from Earth. Our solar system is located in one of the spiral arms of the Milky Way, which is why we are so far from the galactic center. If we could see this in the night sky, the black hole would appear to be the same size as a donut sitting on the moon.

“We were surprised by how well the size of the ring fit the predictions of Einstein’s general theory of relativity,” said Jeffrey Bauer, EHT project scientist from the Institute of Astronomy and Astrophysics, Academia Sinica, Taipei, in a statement.

“These unprecedented observations have greatly improved our understanding of what is happening (in the center of) our galaxy and provided new insights into how these giant black holes interact with their surroundings.”

I’m looking for a black hole

It took astronomers five years to capture and confirm this image and discovery. Scientists have previously observed stars orbiting some massive, unseen objects in the center of the galaxy.

Ramesh Narayan, theoretical astrophysicist at the Center for Astrophysics: “Now we see that the black hole is swallowing gas and light nearby and pulling them into a bottomless crater” | Harvard and Smithsonian, in a statement. “This image confirms decades of theoretical work to understand how black holes erode.”

This discovery was made possible by more than 300 researchers from 80 institutions working with the network of eight different radio telescopes around the world that make up the Event Horizon Telescope.

The telescope is named after the “event horizon,” the point at which light cannot escape the black hole. This global network of telescopes essentially constitutes one virtual “Earth-size” telescope when all eight are connected and the observations are side by side.

Although the two images are similar, arc A* is more than 1,000 times smaller than M87*.

“We have two completely different types of galaxies and two completely different masses of black holes, but near the edge of these black holes they look remarkably similar,” said Sera Markov, co-chair of the EHT Science Council and professor of theoretical astrophysics at the institute. University of Amsterdam in a statement.

“This tells us that (Einstein’s general theory of relativity) closely governs these things, and any differences we see further away must be due to differences in the matter surrounding black holes.”

Unable to take a picture

Although the Milky Way’s black hole is closer to Earth, it was difficult to photograph.

“Gas near black holes is moving at the same speed — roughly the same speed of light — around Sgr A* and M87*,” EHT scientist Chi Kuan Chan at the Steward Observatory and the Department of Astronomy and Data Science at the University of Arizona said in a statement.

But when the gas takes days or weeks to orbit the larger M87*, in the much smaller Sgr A* it completes an orbit in a few minutes. This means that the glow and pattern of the gas around Sgr A* were changing rapidly as EHT cooperation was observed—a bit like trying to capture a clear picture of a puppy chasing its tail quickly. “

The global network of astronomers had to develop new instruments to allow the rapid movement of gas around Sagittarius A*. The resulting image is the average of the various images the team took. Capturing the image of Sagittarius A* was like taking a picture of a grain of salt in New York with a camera in Los Angeles, according to researchers at the California Institute of Technology.

This Event Horizon Telescope image requires more than just taking a picture of telescopes in the high mountains. It’s the product of technically challenging telescope observations and innovative computational algorithms, Katherine Bowman, a Rosenberg researcher and assistant professor of computing sciences, mathematics, electrical engineering and astronomy at Caltech, said during a press conference.

Each telescope was pushed to its maximum limit, which is called the diffraction limit, or the maximum number of features that can be seen per minute.

“And that’s basically the level we’re seeing here,” Johnson said at the press conference. “It is not clear why, to make the image clearer, we need to move our telescopes away or move to higher frequencies.”

Understanding

Imaging two completely different black holes will allow astronomers to identify their similarities and differences and better understand how gas behaves around supermassive black holes, which can contribute to the formation and evolution of galaxies. Black holes are believed to be at the center of most galaxies and act as their engines.

Meanwhile, the EHT team is working to expand the telescope’s network and make updates that could lead to more impressive images and even movies of black holes in the future.

Capturing a moving black hole can show how it changes over time and what the gas does as it orbits the black hole. Bowman and EHT member Antonio Fuentes, who will join Caltech as a postdoctoral researcher in October, are developing methods that allow images of black holes to be linked to reflect this motion.

This “first direct image of the gentle giant at the center of our galaxy” is just the beginning, said Ferial Ozil, a member of the EHT Science Council and professor of astronomy and physics and associate dean for research at the University of Arizona. Press Conference.

“This image is a testament to what we can achieve as we bring our brightest minds together as a global research community to make the seemingly impossible and possible,” National Science Foundation Director Sithuraman Panchanathan said in a statement. “Language, continents, and even the galaxy cannot stop what humanity can achieve when we unite for the common good of all.”