Astronomers prove that Einstein's theory of relativity holds up even for massive three-star system

Astronomers confirm that all objects fall the same way regardless of mass or composition

A group of astronomers at the The University of British Columbia (UBC) have proved that Einstein's theory of general relativity holds up, even for a massive three-star system.

In Einstein's theory, the science legend states that all objects fall the same way regardless of their mass or composition, for example, dropping a cannonball and an apple from the Leaning Tower of Pisa and them both hitting the ground at the same time.

While this theory has proven to work in different situations, many have hypothesised that there are circumstances when alternative theories of gravity would be at play, such as in instances of extreme gravity.

However, new research published in Nature confirms otherwise and claims that Einstein was right: that even in an extreme gravity system, his theory of relativity still applies.

"This research shows how routine and careful observation of distant stars can give us a high-precision test of one of the fundamental theories of physics," said professor in the department of physics and astronomy at UBC and a co-author of the study, Ingrid Stairs.

The proven theory comes after the university studied a three-star system known as PSR J0337+1715, which is located 4,200 light years away and is made up of two white dwarfs and a neutron star.

In the three-star system, the neutron star is in a 1.6-day orbit with one white dwarf, and the second white dwarf orbits this pair with a period of 327 days.

By tracking the inner pair of stars through the course of several orbits of the outer white dwarf, scientists could measure whether the pulsar and inner white dwarf were affected differently by the gravity of the outer white dwarf.

Over time, the researchers found almost no detectable difference, indicating there is little room for alternative theories of gravity in this model.

"If there is a difference, it is no more than three parts in a million," said co-author of the study, Nina Gusinskaia. "Now, anyone with an alternative theory of gravity has an even narrower range of possibilities that their theory has to fit into, in order to match what we have seen."

Stairs added that every single time they've tested Einstein's theory of relativity so far, the results have been consistent.

"But we keep looking for departures from relativity because that might help us understand how to describe gravity and quantum mechanics with the same mathematical language," he added.