Astronomers have observed the fleeting appearance of a bubble of gas that circulates at “mind-boggling” speeds around the black hole at the center of our Milky Way galaxy, according to a study. The duration of the phenomenon did not exceed a few hours.
The detection of this bubble could provide information about the behavior of black holes, says the study published last week. These astronomical objects are all the more mysterious because they are literally invisible, their gravitational pull is such that even light cannot escape.
Sagittarius A* is a black hole four million times more massive than our Sun that resides at the center of our Milky Way galaxy. This so-called supermassive object is about 27,000 light-years from Earth. It was detected thanks to the movement of the stars that orbited around it.
>> Simulation of the orbit of the stars around Sagittarius A* in the center of the Milky Way:
The EHT collaboration, a worldwide network of radio telescopes, published last May the first picture of the ring of material surrounding the black hole before being sucked into it.
>> Read: The supermassive black hole at the center of our galaxy finally photographed
SOUL, one of these radio telescopes, located in the Andes of Chile, captured a “very surprising” signal in the observation data of Sagittarius A* in April 2017, astrophysicist Maciek Wielgus, from the German Max Planck Institute, first Author. of this scientific article. Minutes before the collection of these data by ALMA, the space telescope Chandra detected “a huge emission” of X-rays from Sagittarius A*, he detailed.
original magnetic
This burst of energy, thought to be similar to solar storms on the Sun, sent a bubble of gas flying around the black hole at full speed, according to the study published in the journal Astronomy and Astrophysics. This glowing ball spins in an orbit similar in size to that of the planet Mercury.
ALMA (Atacama Large Millimeter/submillimeter Array) observes the Milky Way and the location of Sagittarius A*, the supermassive black hole at the center of our galaxy. The image of Sgr A* taken by the Event Horizon Telescope (EHT) collaboration is highlighted in the inset. Located in the Atacama desert in Chile, ALMA is the most sensitive of all the observatories in the EHT network. [ESO/José Francisco Salgado (josefrancisco.org) – EHT Collaboration]The phenomenon observed for about an hour and a half made it possible to calculate that the gas bubble – also called a “hot spot” – made a complete orbit around the black hole, clockwise, in just 70 minutes, or at a speed equivalent to 30% of that of light, which reaches 300,000 km per second: a speed that “defies the imagination”, according to Maciek Wielgus. Astronomers also predict that this gas phenomenon will become fainter and brighter as it surrounds the black hole.
This hot spot would be of magnetic origin, according to a theory presented by the scientist. The black hole’s magnetic field is so powerful that it prevents some of the matter that circulates around it from being absorbed by it. But this accumulation of material gives rise to a “flux eruption”, which opens a gap in the magnetic field and releases a burst of energy, in the form of a gas bubble, according to the astrophysicist.
Observations of these magnetic fields should help us understand how black holes work. They could also indicate how fast these black holes are spinning. That’s Maciek Wielgus’s hope: “Hopefully one day we’ll be comfortable enough to say we ‘know’ what’s going on in Sagittarius A*,” he said. completed.
>> Read also: Humanity sees a black hole for the first time in history
Stéphanie Jaquet and the ats