There is already a black hole at the heart of our galaxy. Sagittarius A has been immortalized, for the first time, in images thanks to an international collaboration of astronomers. “Historic moment”, interacts Thursday, May 12 in France Eric Lagadec, astrophysicist at the Côte d’Azur Observatory and president of the French Society for Astronomy and Astrophysics. This shot comes three years after the first image of a black hole, located in the distant galaxy M87. Sagittarius A has a mass of about four million suns and is 27,000 light-years away from Earth.
franceinfo: Why is this a historic moment?
Eric Lagadec: I would say we have two beds. We have the solar system around which the sun, earth, and other planets revolve. And there’s also the Milky Way, our own galaxy. Since mankind, it was clearly easy to observe the sun. But there since 1933, we know there’s something amazing at the galactic center, which is that we have a source of radiation, and then we realize it was compressed. Observations were able to show that there were stars orbiting around it very quickly, and that it was a black hole.
“Today is the first time in human history that we see this black hole in the center of our galaxy. It’s a historic moment.”Eric Lagadec, President of the French Society for Astronomy and Astrophysics
What do we learn from this picture?
We learn a lot of things. Many say that the picture is blurry, but it is the sharpest in human history. What we see there is the equivalent of a Munich beer bubble observed from New York. It’s really a very, very small thing. It’s a beautiful, mind-blowing picture. And what we learned is a good confirmation of Einstein’s theory.
Black holes, have they always been one of the biggest mysteries of physics?
It’s something that makes you dream and it’s a little scary. It’s a very complicated thing to deal with and there, we see it.
“Today, thanks to this image, we learned that the black hole is rotating, and we were able to determine its size and specifically determine its direction.”Eric Lagadec, President of the French Society for Astronomy and Astrophysics
It looks a bit like a donut, which is amazing we can see from above.
What’s more complicated about the black hole story is that we’re talking about something we haven’t yet been able to see and that is so heavy when we don’t?
A black hole, a simple way to see it is: Imagine, you take something, you throw it, it will fall. If you take a rocket: after a certain speed, it will be able to escape from Earth’s gravitational field and you will be able to go into orbit. The black hole is so dense, it’s so heavy that to escape from it you must pass faster than light. So we can’t escape from it. When you enter a black hole, you cannot exit. In the photo, we still see something shiny. In the middle is the shadow of the black hole and around it, which is orange in the image, is gas absorbed by the black hole. Sometimes science goes beyond science fiction.