October 4, 2012
New Star Discovery Paves Way For Tests Of Einstein’s Space-Time
Lee Rannals for redOrbit.com — Your Universe Online
Astronomers, using the Keck Observatory, have found the star they need to test Einstein's theory about the fabric of space-time.
The star, S0-102, orbits the black hole every 11-and-a-half years, which is shorter than the S0-2 that orbits the Milky Way's black hole every 16 years.
"I´m extremely pleased to find two stars that orbit our galaxy´s supermassive black hole in much less than a human lifetime," Andrea Ghez, leader of the discovery team and professor of physics and astronomy, 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“¦This measurement cannot be done with one star alone."
Taft Armandroff, Director of the W. M. Keck Observatory, said this research has evolved from proving a supermassive black hole exists in the Milky Way to testing the fundamentals of physics.
Ghez said that with the closeness of these stars, it will open up all kinds of experiments for scientists to perform over time to understand how black holes grow, the role they play in the center of galaxies and whether Einstein's theory of general relatively is valid near a black hole.
"This should not be a neighborhood where stars feel particularly welcome,” she said in the statement. "Surprisingly, it seems that black holes are not as hostile to stars as was previously speculated."
She said the motion of S0-102 and S0-02 would be the ultimate test for Einstein's theory of general relatively. This theory describes gravity as a consequence of the curvature of space and time.
"The exciting thing about seeing stars go through their complete orbit is not only that you can prove that a black hole exists, but you have the first opportunity to test fundamental physics using the motions of these stars," Ghez said. "Showing that it goes around in an ellipse provides the mass of the supermassive black hole, but if we can improve the precision of the measurements, we can see deviations from a perfect ellipse -- which is the signature of general relativity."
As the stars come to their closest approach of the black hole, their motion will be affected by the curvature of space-time and the light traveling from the stars will start to seem distorted to us.
Einstein has been able to do more than just provide science fiction authors something to dream about, Leo Meyer, a researcher in Ghez´s team and lead author of the study said. The great scientist's theories have had an effect on one particular device we use every day.
"Today, Einstein is in every iPhone, because the GPS system would not work without his theory," Meyer said in a statement. "What we want to find out is, would your phone also work so close to a black hole? The newly discovered star puts us in a position to answer that question in the future."
The researchers will be reporting the details of their finding of S0-102 in the journal Science on Friday.