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You'd think a binary pulsar would be ideal for measuring gravitational waves: they're precise clocks swimming in rapidly changing gravitational fields. Interes
by biswaroop 11y ago
You'd think a binary pulsar would be ideal for measuring gravitational waves: they're precise clocks swimming in rapidly changing gravitational fields.
Interestingly, binary systems of pulsars are the only source of evidence for gravitational waves. Astronomers use the pulsar timing to detect the slowing of orbital motion due to gravitational wave emission. I wonder if it's possible to detect a 'local gravitational wave background' modulating the pulsar timing on top of the usual modulation from the slowing binary.
- raverbashing 11y ago> Astronomers use the pulsar timing to detect the slowing of orbital motion due to gravitational wave emission. Correct, at least that's the theory But that's not evidence of gravitational waves per se, rather an evidence that a spinning binary system will have a velocity decay (and gravitational waves fit the description of what might be happening) So maybe there's an issue with how we measure it, how it actually affects matter or "it's complicated"/"it doesn't exist"
- versteegen 11y agoBut the rate of orbital decay of pulsars in binary systems is very precisely matched by general relativity, which is going to be very hard to explain with a different cause. Given that GR has been verified so thoroughly, while on the other hand models of the gravitational background depend on so many assumptions and simulations and approximately measured empirical relationships about supermassive black hole (SMBH) sizes, occurrences, time for SMBH mergers, etc, as detailed in the article, clearly this is incredibly weak evidence that gravitational waves don't exist. But something is wrong somewhere.