This artist’s illustration shows a cross-section of the supermassive black hole at the center of our galaxy and the material surrounding it. The black sphere in the center represents the black hole’s event horizon, the point of no return from which nothing, not even light, can escape. When looking at a rotating black hole from the side, as shown in this illustration, the space-time surrounding it appears to be shaped like an American football.

The yellow-orange material on either side represents the gas orbiting the black hole. This material inevitably sinks into the black hole and crosses the event horizon once inside the football jersey. Thus, a football-shaped area outside the event horizon is depicted as space. Blue spots show jets emerging from the poles of the spinning black hole.

• A new study may help resolve the question of how fast the Milky Way’s supermassive black hole is spinning.
• The black hole, known as Sagittarius A* (Sgr A*), contains approximately 4 million solar masses.
• This study, using NASA’s Chandra X-ray Observatory and NSF’s Very Large Array, found that Sgr A* rotates very quickly.
• This high spin distorts the space-time around Sgr A*, making it appear shaped like an American football.

This artist’s illustration depicts the results of a new study of the supermassive black hole at the center of our galaxy called Sagittarius A* (abbreviated as Sgr A*). This result showed that Sgr A* was spinning so fast that it distorted space-time, that is, time and the three dimensions of space, so that it looked more like a football.

These results were obtained using NASA’s Chandra X-ray Observatory and NSF’s Carl G. Jansky Very Large Array (VLA). A team of researchers used a new method that uses X-ray and radio data to determine how fast Sgr A* is spinning based on the way material moves toward and away from the black hole. They found that Sgr A* rotates with an angular velocity of about 60% of the maximum possible value and an angular momentum of about 90% of the maximum possible value.

Black holes have two basic properties: their mass (how much they weigh) and spin (how fast they spin). Determining either of these two values ​​will tell scientists a lot about any black hole and how it behaves. Astronomers have made several other estimates of Sgr A*’s spin rate in the past using different methods; results ranged from Sgr A* not spinning at all to spinning at near maximum speed.

A new study shows that Sgr A* is actually spinning very fast, causing the space-time around it to compress. The figure shows a cross-section of Sgr A* and the material orbiting it in the disk. The black sphere in the center represents the so-called event horizon of the black hole, the point of no return from which nothing, not even light, can escape.

When looking at a rotating black hole from the side, as shown in this drawing, the space-time surrounding it appears to be shaped like a football. The faster it spins, the straighter the ball.

The yellow-orange material on either side represents gas in the Sgr A* orbit. This material inevitably sinks into the black hole and crosses the event horizon once inside the football jersey. Thus, a football-shaped area outside the event horizon is depicted as space. Blue spots show jets emerging from the poles of the spinning black hole. If you look at a black hole from above along its jet shaft, spacetime appears to have a circular shape.

The spin of a black hole can serve as an important source of energy. Spinning supermassive black holes form parallelized flows like jets when their rotational energy is removed; This requires at least some matter to be present near the black hole. Due to the limited fuel around Sgr A*, this black hole has remained relatively quiet over the last millennia, with relatively weak jets. However, this study shows that this may change if the amount of material near Sgr A* increases.

To determine Sgr A*’s spin, the authors used an empirically based technique called the “outflow method,” which details the relationship between the black hole’s spin and its mass, the properties of matter near the black hole, and the properties of the black hole itself. exit. The collimated flow produces radio waves, while the disk of gas surrounding the black hole is responsible for X-rays. Using this method, the researchers combined Chandra and VLA data with independent estimates of the black hole’s mass from other telescopes to constrain the black hole’s spin.