BEIJING, Jan. 7 (Xinhuanet) -- A newly discovered three-star system may challenge a key concept in Albert Einstein's Theory of Relativity, according to a report published Monday in the journal Nature.
The three-star system is composed of two white dwarf stars and a superdense pulsar spinning at 366 times per second, and all three stars are packed within a space smaller than the Earth's orbit around the sun. The system is about 4,200 light years away from the Earth.
The system offers the best opportunity to test a possible violation of a key concept in Albert Einstein's theory of General Relativity: the strong equivalence principle, which states that the effect of gravity on a body does not depend on the nature or internal structure of that body, said the researchers from the University of British Columbia (UBC).
When a massive star explodes as a supernova and its remains collapse into a superdense neutron star, some of its mass is converted into gravitational binding energy that holds the dense star together; the strong equivalence principle says that this binding energy will still react gravitationally as if it were mass, while several proposed alternatives to General Relativity hold that it will not.
"Under the strong equivalence principle, the gravitational effect of the outer white dwarf would be identical for both the inner white dwarf and the neutron star. If the strong equivalence principle is invalid under the conditions in this system, the outer star's gravitational effect on the inner white dwarf and the neutron star would be slightly different and the high-precision pulsar timing observations could easily show that," UBC wrote in a statement.
Study leader Scott Ransom, the National Radio Astronomy Observatory, said that the star system is intriguing because it must have come to be under a completely “crazy” formation history, and much work has to be done to fully understand it.