In Chile, astronomers using the world’s largest telescopes discovered a star revolving around a black hole in the Milky Way, just as Albert Einstein had projected more than a hundred years ago.
One of the foundations of modern physics is Einstein’s General Theory of Relativity, published in 1915. This theory has helped scientists understand gravitational forces for a long time.
Nonetheless, Thursday’s statement from the European Southern Observatory (ESO), an intergovernmental organization of European astronomers working in Chile, proves that the hypothesis still extends to a star about 26,000 light-years distant from the Sun.
Throughout space, most celestial bodies would have circular or elliptical orbits. Yet now nearly 30 years of measurements have shown that a star in the middle of our galaxy circles the supermassive black hole Sagittarius A* (Sgr A*) in the form of a rosette or spirograph. Once again, the observation supports the statement produced by Einstein’s General Relativity.
Astronomers with the ESO have been observing this star — named S2—orbit our nearby supermassive black hole for about 30 years, taking precise measurements of the direction and velocity of the star as it swirls through the galactic core. After observing the star perform almost two full orbits (each perform orbit takes around 16 years), the researchers hypothesized that the star might not have a defined elliptical orbit as expected by Isaac Newton’s Gravitational Theory, but instead “dances” around the black hole in a pattern that resembles a rosette drawn with a spirograph.
Due to the incredibly strong gravitational force of Sgr A*, S2 speeds up as it sinks towards the black hole, until it slings away, slows down, and is finally forced down towards the black hole.
Beyond throwing another log to the symbolic fire of Einstein’s legend, the discovery may also enable researchers to make more precise measurements of the forms and amounts of matter at the heart of the galaxy, the researchers said.
“Because the S2 measurements follow general relativity so well, we can set stringent limits on how much invisible material, such as distributed dark matter or possible smaller black holes, is present,” study co-authors Guy Perrin of the Paris Observatory and Karine Perraut of the France’s University of Grenoble said in the statement. “This is of great interest for understanding the formation and evolution of supermassive black holes.”