Albert Einstein’s theory of general relativity is still holding up 100 years after he first published it but it is beginning to fray, new research shows.
UCLA researchers co-led by Tuan Do and Andrea Ghez, professors of physics and astronomy at UCLA, made direct measurements of general relativity near a supermassive black hole at the center of the Milky Way and found Einstein’s theory still stands. It's the culmination of more than two decades of work in the area.
Einstein's Theory of General Relativity Still Holds Up
"Einstein's right, at least for now," said Ghez of the research in a press release announcing the results. "We can absolutely rule out Newton's law of gravity. Our observations are consistent with Einstein's theory of general relativity. However, his theory is definitely showing vulnerability. It cannot fully explain gravity inside a black hole, and at some point, we will need to move beyond Einstein's theory to a more comprehensive theory of gravity that explains what a black hole is.”
Einstein’s theory of general relativity dates back to 1915 and states the force of gravity arises from the curvature of space and time. Objects such as the sun and Earth change that. His theory still stands as the best description of how gravity works, said Ghez. Her research team is one of only two that have studied the S0-2 star make a complete orbit in three dimensions around the supermassive black hole. The full orbit takes sixteen years as the black hole is four million times that of the sun.
Researchers Studied the S0-2 Star Make its Way Around a Black Hole
Do, Ghez and the other researchers analyzed new observations of the S0-2 star in 2018 as it made its closest approach to the black hole. The data from that was combined with the measurement Ghez and the team collected over the past 24 years. The results are consistent with the general relativity.
"What's so special about S0-2 is we have its complete orbit in three dimensions," said Ghez. "That's what gives us the entry ticket into the tests of general relativity. We asked how gravity behaves near a supermassive black hole and whether Einstein's theory is telling us the full story. Seeing stars go through their complete orbit provides the first opportunity to test fundamental physics using the motions of these stars."
Researchers Dispel Newton's Law of Gravity
The research also dispels Newton’s Law of Gravity which contends space and time are separate and do not commingle. The Ghez led research team saw co-mingling of space and time near the supermassive black hole.
"Making a measurement of such fundamental importance has required years of patient observing, enabled by state-of-the-art technology," said Richard Green, director of the National Science Foundation's division of astronomical sciences in the same release. For more than twenty years the unit has supported Ghez in her work. "Through their rigorous efforts, Ghez and her collaborators have produced a high-significance validation of Einstein's idea about strong gravity."