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A comment on Rumours swell over new kind of gravitational-wave sighting. Parent comment

Re:Rumours swell over new kind of gravitational-wave sighting by Koshkin on Saturday August 26, 2017 @09:08PM (#15108441)
> we're slowly narrowing in on C in measurements

Interesting... I thought that c = 299,792,458 m/s exactly. So what are we are actually measuring here? The meter and/or the second?

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Re:Rumours swell over new kind of gravitational-wave sighting by ekimekim on Saturday August 26, 2017 @09:16PM (#15108473)
I believe the OP meant that they're narrowing in on being confident that gravitational waves travel at C, not narrowing in on a more precise value of C.

That said, if we do obtain a more precise value of C, the definition that changes is the meter. The second is defined in terms of energy states of a caesium atom.

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Re:Rumours swell over new kind of gravitational-wave sighting by Filligree on Sunday August 27, 2017 @12:40PM (#15111480)
Right you are. I wrote that a bit ambiguously.
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