5 SEP 2019

After 14 years of staring at a dead star, astronomers have once again confirmed Einstein’s theory of general relativity. PSR J1906+0746, a pulsar 25,000 light-years away, slightly wobbles as it spins – an effect that could see its pulses disappear from our sky in less than a decade.

It’s called precession, a phenomenon predicted by general relativity that has only ever been observed in very few pulsars. The new findings could help us set a limit on the number of binary pulsars in the galaxy, in turn helping us figure out the expected rate of binary neutron star collisions. 

Pulsars are perhaps the most useful stars in the sky. They are rapidly spinning neutron stars with jets of bright radio waves emitting from their magnetic poles. As they spin, these beams can sweep past Earth, depending how the star is oriented: a bit like a lighthouse.

They’re also incredibly precise, with rotations that can be predicted up to millisecond scales. These so-called millisecond pulsars can keep such precise time that they could guide future space navigation.

But even the majority of pulsars – ones that don’t have that millisecond level of precision – are still useful, particularly for tests of general relativity. That’s because, according to general relativity, pulsars in binary systems should have a slight axial wobble (think of a slowing-down spinnin

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