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Stellar Triplet Weakens Rival Relativity Theories

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Astronomers observing the complicated orbital dance of three compact stars have concluded that Einstein’s theory of general relativity still can’t be proven wrong.

Einstein’s strong equivalence principle says that all objects should fall the same way in a gravitational field, regardless of their composition or how dense they are. The triple-stellar system discovered in 2012 was considered the perfect system to test the theory due to the substantial differences in the make-up of the three stars. “This particular system consists of one ultra-dense neutron star and two less-dense white dwarf stars, which makes these stars the dream team for testing relativity,” said Dr Adam Deller of Swinburne University.

Making the whole test possible was the fact that the neutron star can be observed as a radio pulsar, meaning the bright beam of electromagnetic radiation that it emits can be detected from Earth. “The radio pulsar star acts like a clock on the sky. It spins in a very predictable way, and each time it sweeps past the Earth we see a little blip of radio emission, which we can treat like the ticks of a clock.”

After 5 years of intensive observation of the system, the international research team concluded in Nature ( that the theory of general relativity remains relevant...

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