Albert Einstein’s gravity theory passes another test yet again

Albert Einstein’s theories on general relativity hold true even in one of the most extreme scenarios the universe can offer, according to a study.

Einstein, in his general theory of relativity, predicted that all objects fall at the same rate, regardless of their mass or composition.

From careful laboratory studies to observations of planets in our solar system, Einstein’s equations have passed all tests.

Scientists, however, have wondered whether it still holds true for some of the most massive and dense objects in the known universe. Alternatives to Einstein’s general theory of relativity predict that compact objects with extremely strong gravity, like neutron stars, fall a little differently than objects of lesser mass.

An international team of astronomers tested this question by studying three stars orbiting each other about 4,200 light years from Earth.

Even in one of the most extreme scenario, according to the new findings, it showed that Einstein’s insights into gravity is true yet again.

In 2011, the National Science Foundation’s (NSF) Green Bank Telescope (GBT) found a way to test this theory in extreme conditions using an existing star system as a laboratory.

A triple star system called PSR J0337+1715, located about 4,200 light-years from Earth was chosen for the study.

This system contains a neutron star in a 1.6-day orbit with a white dwarf star, and the pair in a 327-day orbit with another white dwarf further away.

“This is a unique star system. We don’t know of any others quite like it. That makes it a one-of-a-kind laboratory for putting Einstein’s theories to the test,” Ryan Lynch of the Green Bank Observatory in the US said.

If Einstein’s proposed theory on gravity was correct, the neutron star and the inner white dwarf would each fall differently towards the outer white dwarf.

“The inner white dwarf is not as massive or compact as the neutron star, and thus has less gravitational binding energy,” said Scott Ransom, an astronomer with the National Radio Astronomy Observatory in the US.

Through meticulous observations and careful calculations, the researchers were able to test the system’s gravity using the pulses of the neutron star alone.

Researchers found that any acceleration difference between the neutron star and inner white dwarf is too small to detect.

“If there is a difference, it is no more than three parts in a million,” said Nina Gusinskaia from the University of Amsterdam in the Netherlands.

Researchers said the result is ten times more precise that the previous best test of gravity, making the evidence for Einstein’s Strong Equivalence Principle that much stronger.

The study was published in the journal Nature.

(With inputs from agencies)