On Fri, 2 Jan 2009, Rob Seaman wrote: > > So yes, I think the angular momentum of the Earth is more real than the > observations that might be compiled to generate an estimate for its value.
But the value is an estimate, so if you plug numbers into a model based on this estimate you are only going to get an estimate to apparent solar time. In fact, since the model has to include a value for the earth's unpredictably variable moment of inertia, the result of using the model is going to be less accurate than the estimate you started with. (Um, do we actually know the earth's angular momentum and moment of inertia to any useful accuracy? I would have thought models would be based directly on angular velocity since that can be measured more precisely.) I think it's wrong to say that a directly measurable value (such as apparent solar time) is less real when measured than when derived from a model! Perhaps the word you are looking for is "fundamental". Tony. -- f.anthony.n.finch <[email protected]> http://dotat.at/ FITZROY: NORTHWESTERLY IN SOUTH AT FIRST, OTHERWISE EASTERLY BACKING NORTHEASTERLY, 5 OR 6, OCCASIONALLY 6 AT FIRST, BECOMING VARIABLE 4 IN FAR NORTHWEST LATER. ROUGH. RAIN OR SHOWERS. MODERATE OR GOOD. _______________________________________________ LEAPSECS mailing list [email protected] http://six.pairlist.net/mailman/listinfo/leapsecs
