The Laser Interferometer Gravitational-Wave Observatory, or LIGO, has detected the ripple effect caused by gravitational waves in space for the very first time. This finding is important because it suggests that one of the most widespread interpretations of Albert Einstein’s century-old theory about relativity could be correct.
However, Forbes contributor Sabine Hossenfelder doesn’t think LIGO’s successful test proves the existence of quantum gravity or that the coalition will ever be able to do it.
LIGO to continue testing
One successful observation of gravitational waves in space doesn’t prove the quantum gravity theory, although most scientists think it’s a step in the right direction. Currently, there’s a missing link between Einstein’s General Theory of Relativity and quantum mechanics, which is where the quest for a theory of quantum gravity comes from. Physicists have been avidly searching for that link, which is where the idea of quantum gravity comes from.
Einstein’s Theory of Relativity states that gravitational waves, which are produced by objects that are accelerating, send ripples through space-time, and LIGO plans to test what it observed many more times. Basically what it boils down to is that the U.S.-led group directly detected these gravitational waves through time and space for the very first time.
Quantum gravity not needed to explain gravitational waves
Hossenfelder said in her post on Forbes that quantum gravity isn’t needed to explain gravitational waves although physicists widely believe that quantum gravity causes gravitons, or “quantized gravitational waves,” as she calls them. She also describes gravitons as “a tiny chunk of the wave with an energy proportional to the wave’s frequency.” Further, she said each gravitational wave is made up of “a huge number” of them, although currently scientists can’t measure them.
Because of how many gravitons are believes to make up a gravitational wave, she said detectors can’t pick up individual particles because there are so many of them. They’re also not “sensitive to the tiny, discrete steps in energy,” she explained. In other words, LIGO hasn’t proven that gravitons exist, and if they do exist, then the group can observe them in the form of a gravitational wave without being able to detect gravitons.
“As to whether it can tell us something about quantum gravity, I can’t tell you with certainty, because we don’t have a theory of quantum gravity,” she wrote. “So the answer to this question depends on what you believe we know about quantum gravity.”