A star that is pirouetting around the supermassive black hole at the center of the Milky Way, our galaxy, has validated a key part of Albert Einstein's theory of general relativity. The star, called S2, is like "a precision probe of the gravitational field around the closest massive black hole," according to a study published on Thursday in Astronomy & Astrophysics.

For decades, scientists have gazed across 26,000 light years to watch S2 orbiting Sagittarius A*, our galactic center, which is occupied by a black hole with an estimated mass of four million Suns.

S2 is a perfect natural laboratory to test out some of Einstein's predictions about the environment near extremely massive objects, including a phenomenon called Schwarzschild precession. This precession occurs when an object is locked in a very close orbit with a much more massive object. Instead of tracing out the same elliptical orbit, as modeled in Newtonian physics, general relativity predicts that the smaller object will have an orbit shaped like a stenciled rosette, due to the curvature of spacetime around the massive object.