General relativity passes a range of precise tests set by pair of extreme stars

“ This cosmic laboratory known as the “Double Pulsar” was discovered by members of the team in 2003. It consists of two radio pulsars which orbit each other in just 147 min with velocities of about 1 million km/h. One pulsar is spinning very fast, about 44 times a second. The companion is young and has a rotation period of 2.8 seconds. It is their motion around each other which can be used as a near perfect gravity laboratory.

Prof Dick Manchester from Australia's national science agency, CSIRO, illustrates: “Such fast orbital motion of compact objects like these - they are about 30% more massive than the Sun but only about 24 km across - allows us to test many different predictions of general relativity - seven in total! Apart from gravitational waves, our precision allows us to probe the effects of light propagation, such as the so-called “Shapiro delay” and light-bending. We also measure the effect of “time dilation” that makes clocks run slower in gravitational fields. We even need to take Einstein's famous equation E = mc2 into account when considering the effect of the electromagnetic radiation emitted by the fast-spinning pulsar on the orbital motion. This radiation corresponds to a mass loss of 8 million tonnes per second! While this seems a lot, it is only a tiny fraction - 3 parts in a thousand billion billion(!) - of the mass of the pulsar per second.”

It’s so beautiful that these things are just existing out there with such intensity that we would die instantly if we tried to see it.

Re: General relativity passes a range of precise tests set by pair of extreme stars

#6

Post by RcouF1uZ4gsC » Thu, Dec 16, 2021, 4:08 AM UTC

mensetmanusman wrote: post #5

“ This cosmic laboratory known as the “Double Pulsar” was discovered by members of the team in 2003. It consists of two radio pulsars which orbit each other in just 147 min with velocities of about 1 million km/h. One pulsar is spinning very fast, about 44 times a second. The companion is young and has a rotation period of 2.8 seconds. It is their motion around each other which can be used as a near perfect gravity l…

To put this in perspective, our sun loses around 4 million tons per second, so it is about twice the radiation of the sun

Re: General relativity passes a range of precise tests set by pair of extreme stars

#7

Post by fsh » Thu, Dec 16, 2021, 4:22 AM UTC

waynecochran wrote: post #2

Fantastic! Was the orbit of Mercury early in the 20th centruy the first confirmation?

It was known since the 1850s that the perihelion precession of Mercury is a few percent larger than predicted by Newtonian mechanics. This even led to speculations that there might be another undiscovered planet ("Vulcan") in a close orbit around the sun. In 1916 Einstein calculated that this effect could be fully explained by General Relativity. Another famous prediction is that of the deflection of light that passes close to a star. This was confirmed by Eddington during the 1919 solar eclipse.

Re: General relativity passes a range of precise tests set by pair of extreme stars

#8

Post by dev_tty01 » Thu, Dec 16, 2021, 4:27 AM UTC

fouc wrote: post #3

It's not even nine nines? Only 99.9%

I think you've got a typo, it was 99.99%. "Einstein’s theory, which was conceived when neither these types of extreme stars nor the techniques used to study them could be imagined, agrees with the observation at a level of at least 99.99%." Either way, incredible stuff. I'm impressed the experimental data is that accurate.

Re: General relativity passes a range of precise tests set by pair of extreme stars

#9

Post by kanzenryu2 » Thu, Dec 16, 2021, 5:28 AM UTC

This does worry me, though https://en.wikipedia.org/wiki/Flyby_anomaly

Re: General relativity passes a range of precise tests set by pair of extreme stars

#10

Post by behnamoh » Thu, Dec 16, 2021, 5:43 AM UTC

mensetmanusman wrote: post #5

“ This cosmic laboratory known as the “Double Pulsar” was discovered by members of the team in 2003. It consists of two radio pulsars which orbit each other in just 147 min with velocities of about 1 million km/h. One pulsar is spinning very fast, about 44 times a second. The companion is young and has a rotation period of 2.8 seconds. It is their motion around each other which can be used as a near perfect gravity l…

My jaw (and my phone) dropped when I read the numbers. I feel like space is ruthlessly huge and these pulsars are brutally massive..