Earth's spindown

Bikeman (Heinz-Bernd Eggenstein)
Bikeman (Heinz-...
Joined: 28 Aug 06
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Topic 193144

Hi ho!

I read in a german article recently that surprisingly, the exact timing of the earth's daily rotation is not yet known exactly enough for some applications in science. I wonder whether this might be true for GW research. There's a project planned (or ongoing?)to measure the spindown more accurately using reference points in space via radioastronomy.

The problem is that the rotation of the Earth is slowing down by a minuscule fraction, so that the GPS time used for most practical purposes as a reference and the "astronomical time" drift apart. On a larger scale, this can be corrected by inserting "leap seconds" every few years, but the target is to have daily corrections some day n the future so that scientist have a very accurate astronomical time.

Does this have any relevance for what we are doing here?



Chipper Q
Chipper Q
Joined: 20 Feb 05
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Earth's spindown

I think it certainly has relevance, but probably doesn't present any major difficulty. I'm guessing time coordinations are based on celestial reference points to begin with, in a heliocentric frame of reference, so by knowing which star an optical telescope is locked on to, it's easy to determine the orientation of the earth in space at any particular time. When you think about it, how else could you measure the spinddown rate? Of course, multiple detectors in different locations also leave little room for doubt...

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