A star's strange orbit around a black hole proves Einstein right again

Albert Einstein's general theory of relativity continues to prove its worth, 108 years after it was officially published .

After nearly three decades of observing S2 - the closest star to the giant black hole at the center of the Milky Way - scientists have finally detected small changes in the distant object's orbit.

S2 has been in an elliptical orbit for more than 15 years , and it made its closest approach to the giant black hole Sagittarius A* late last year; specifically, S2 came within 20 billion kilometers of Sagittarius A*. If Isaac Newton's description of gravity were correct, S2 would have remained in the same orbit as its last flyby. But that didn't happen.

The orbits of S2 create a "spirograph" pattern in space.

According to scientists' observations, S2 has deviated from its orbit 16 years ago, when the elliptical axis (created by S2's orbit) shifted slightly . These details are clearly stated in a report conducted by a team from the Very Large Telescope, and published in the journal Astronomy & Astrophysics.

Orbits of S2 and other stars around the black hole Sagittarius A* - Video: European Southern Observatory (ESO).

In general relativity, the phenomenon that creates this curved orbit is scientifically known as the 'Schwarzschild geodesic', named after the astrophysicist Karl Schwarzschild, who made a major contribution to the interpretation of general relativity.

Due to the influence of the giant black hole, the new orbit of star S2 creates a 'spirograph' as ​​depicted in the video below, and at the same time shows that general relativity is correct again!

ESO artist depicts the trajectory of star S2 - (Video: ESO).

Scientists say tracking S2's trajectory will allow them to study more closely the invisible matter, including smaller black holes or dark matter, that exists around Sagittarius A*. In this way, we can better understand how black holes grow over time.