Star Pair Orbiting Black Hole to Be Space Lab to Test Einstein’s Theory

Astronomers from University of California Los Angeles (UCLA) have discovered a star orbiting a black hole and hope to observe it for testing Einstein's theory.

The star S0-102 orbiting for 11.5 years around the black hole is the second star to have been identified with a short orbit. Earlier astronomers had detected a star, S0-2, which orbits the black hole, in just 16 years.

"I'm extremely pleased to find two stars that orbit our galaxy's super massive black hole in much less than a human lifetime," Andrea Ghez, UCLA professor who has been studying S0-2 since 1995, said in a statement.

"It is the tango of S0-102 and S0-2 that will reveal the true geometry of space and time near a black hole for the first time," she said. 

Ghez and her colleagues are studying the speeding stars orbiting near the black hole to test whether scientist Albert Einstein's theory of relativity, which suggests that mass warps space and time, holds true around a black hole. While the theory has been proved in several other cases, it has so far not been tested around a black hole. 

Black hole is a region of space time which has a powerful gravitational pull. The gravity pull is so strong that any matter, even light, cannot escape its clutches and drawn in to the no point horizon.

The researchers can now test what will happen to the stars that are closely orbiting the black hole. If the Einstein's theory of relativity holds true around the black hole, then the orbiting position of the stars should change for every rotation due to the gravitational pull and produce a daisy-petal pattern, a report in National geographic said.

Experts need to keep track of a complete orbit of a star nearby the black hole periapse to understand its effects on the star. The speeding stars that orbit for a short period will be helpful in learning the process as most other stars take 60 years to orbit a black hole.

Astronomers will be keeping a close tab on the short orbiting star S0- 2, which will be at the nearest to the black hole in 2018, to find out if any changes caused by space time curving occur around the black hole, reported in Science News.

"We know Einstein's theory breaks down when you get to the core, to the center of a black hole - the singularity," Science News quoted Ghez as saying. "A black hole is, almost by definition, the breakdown of Einstein's general relativity."

But what is yet to be found out is the point to which a star can get closer to a black hole before Einstein's theory begins to disintegrate.

The findings of the study, "The Shortest-Known-Period StarOrbiting Our Galaxy's Supermassive Black Hole", are published in the journal Science.