Einstein's theory of general relativity passes one of its toughest tests yet

They achieved an accuracy for GR to as tight as 1 part in a million.

Article states, "So general relativity remains undefeated — but that doesn't mean that researchers should stop trying to find cracks in it. " Yes, that's the way science works! Scrutiny is more than just welcome.

[Nit - GR published Nov. 1915.]
"The pulsar pair that the research team investigated lies about 2,400 light-years from Earth. One of the pulsars spins 44 times per second, whereas the other completes one rotation every 2.8 seconds. The two objects orbit a common center of mass once every 147 minutes, each of them moving through space at around 620,000 mph (1 million kph), team members said."

My note. Using a binary pulsar where both are 1.4 solar masses, this is < 9,000 second period. That suggests the two are separated by about 0.6E-3 au or so (0.006 au). Using a common pulsar radius, their rotation rates could be 22 km/s or so for a 2.8 second spin period. The other could be spinning near 1.43 km/s at its equator. Not particularly fast spins for pulsars.

Correction. *44 times per second* is the pulsar spin rate for one of these reported. That is 0.023 or some 2700 km/s or more spin rate at its equator using 10 km radius.
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My observation for those interested. The NASA ADS Abstract, Strong-field Gravity Tests with the Double Pulsar, https://ui.adsabs.harvard.edu/abs/2021arXiv211206795K/abstract, December 2021. The 56-page arXiv PDF, https://arxiv.org/pdf/2112.06795.pdf, 13-Dec-2021. On page 20, "TABLE IV. Timing parameters for PSR J0737−3039A inTDB units (see text)." shows properties, masses, and semi-major axis and orbital periods of the binary pulsar system used to test GR. "Orbital period, Pb (day) 0.1022515592973(10), "Projected semimajor axis, x (s) 1.415028603(92)", "Eccentricity (Kepler equation), eT 0.087777023(61)", "Total mass, M(Msun) * 2.587052(+9/−7), "Mass of pulsar A, mA (Msun)∗ 1.338185(+12/−14), "Mass of pulsar B, mB (Msun)∗ 1.248868(+13/−11)", "Distance from πc, d (pc) 735(60)".

The 56-page paper is very detailed.
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