This is the first direct observation to confirm the existence of a black hole known as Sagittarius A * as the center of the Milky Way’s heartbeat.
The black hole does not emit light, but the image shows the shadow of the black hole surrounded by a bright ring where the light is bent by the gravity of the black hole. Astronomers said black holes are four million times larger than our sun.
“For decades, astronomers wondered what was in the center of our galaxy, and its enormous gravity pulled the stars into tight orbits,” said the Astrophysicist Center. Astrophysicist Michael Johnson | Harvard & Smithsonian said in a statement.
“Using the (Event Horizon Telescope or EHT) image, we zoomed in to 1000 times these orbits where gravity is 1 million times stronger. At this short distance, a black hole accelerates the material to the speed of light. Bring it closer. Bend the path of the distorted (space-time) photon. “
Black holes are about 27,000 light-years away from Earth. Our solar system is on one of the spiral arms of the Milky Way galaxy, which is why we are so far from the galactic center. If you can see this in the night sky, the black hole looks like a donut sitting on the moon.
“I was surprised at how well the size of the ring matched the predictions from Einstein’s general relativity,” said Jeffrey Bauer, an EHT project scientist at the Institute of Astronomy and Astrophysics in Taipei’s Academia Sinica. Said in a statement.
“These unprecedented observations have greatly improved our understanding of what is happening in the very (center) of our galaxy, and how these giant black holes are around them. It provides new insights into how they interact. ”
Find a black hole
It took astronomers five years to capture and confirm this image and discovery. Previously, scientists were observing stars orbiting giant invisible objects in the galactic center.
“We found that black holes swallowed nearby gas and light and pulled them into the bottomless hole,” said Ramesh Narayan, a theoretical astrophysicist at the Center for Astrophysics. Harvard & Smithsonian said in a statement. “This image supports decades of theoretical research to understand how black holes are eaten.”
This discovery was made possible by more than 300 researchers from 80 institutions working on a network of eight different radio telescopes around the world that make up the Event Horizon Telescope.
The telescope is named after the “event horizon” where light cannot escape from a black hole. This global telescope network basically forms a single “Earth-sized” virtual telescope when all eight are linked and observed in tandem.
The two images are similar, but Sagittarius A * is 1/1000 of M87 *.
“There are two completely different types of galaxies and two very different black hole masses, but close to the edge of these black holes, they are surprisingly similar,” said Co-Chair of the EHT Science Council. Seramarkov, a professor of theoretical astrophysics, said. University of Amsterdam, in a statement.
“This shows that the general theory of relativity dominates these objects close together. The difference seen in the distance must be due to the difference in the materials surrounding the black hole.”
Capture impossible images
The Milky Way black hole is close to the earth, but it was much harder to imagine.
“Gas near a black hole travels around both Sgr A * and M87 * at the same speed (almost as fast as light),” said Steward Observatory and Chi-kwan Chan, an EHT scientist at the Faculty of Astronomy. The University of Arizona’s Institute of Data Science said in a statement.
“But if it takes days or weeks for the gas to orbit the large M87 *, the much smaller Sgr A * will complete the orbit in just a few minutes. This is the brightness of the gas around the Sgr A *. It means that the pattern was changing rapidly as an EHT collaboration. I was observing it-it’s like trying to get a clear picture of a puppy immediately chasing his tail. “
A global network of astronomers had to develop new tools that would allow for the rapid movement of gas around Sagittarius A *. The resulting image is the average of the various images taken by the team. According to researchers at the California Institute of Technology, taking an image of Sagittarius A * was like taking a picture of a grain of salt in New York City with a camera in Los Angeles.
“This image from the Event Horizon Telescope wasn’t enough to take a picture from a telescope on a high mountaintop. It’s the product of both technically difficult telescope observations and innovative computational algorithms.” Said Catherine Boomann, a Rosenberg scholar and assistant professor of computing and mathematical science. , California Institute of Technology electrical engineering and astronomy said at a press conference.
Each telescope was pushed into a limit called the diffraction limit, or the largest subtle feature it can see.
“And that’s basically the level we’re looking at here,” Johnson said at a press conference. “It’s ambiguous because you need to move the telescope further away or move to a higher frequency to create a clearer image.”
On the horizon
By having images of two very different black holes, astronomers can determine their similarities and differences and which gas is around the supermassive black hole, which can contribute to the formation and evolution of the galaxy. You can better understand how it behaves. Black holes are located in the center of most galaxies and are thought to act like engines that power them.
Meanwhile, the EHT team is working to expand the telescope network to carry out even better images of black holes and even upgrades that could lead to movies in the future.
Capturing a moving black hole can show how it changes over time, and what the gas does as it swirls around the black hole. Bouman, who will join the California Institute of Technology as a postdoctoral fellow in October, and Antonio Fuentes, a member of EHT, are developing a way to stitch together images of black holes to reflect this move.
This “first direct image of the calm giant in the center of our galaxy” is just the beginning, a member of the EHT Science Council, a professor of astronomy and physics, and a study at the University of Arizona. Feryal Özel, Deputy Dean of the Department, said: Press conference.
“This image is a testament to what we can achieve. As a global research community, we bring together the brightest minds and enable us to look seemingly impossible,” said the director of the National Science Foundation. Seturaman Panchanasan said in a statement. “Language, continents, and even galaxies cannot prevent humanity from achieving what we can achieve when we come together for the greater benefit of all.”