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Old Aug 13, 2007 | 7:08 pm
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HkCaGu
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Originally Posted by cpx
The signals travel approximately at the speed of 1,079,252,848.8 km/h and by the time they reach you, the time ticks are old already.
I don't believe it's "approximately". The metre/meter is defined as the distance light travels in 1/299 792 458 of a second, so the speed of light is exactly 1 079 252 848 800 m/h. Of course light slows down when it hits the atmosphere.

Greenwich is famous for GMT, which is a measure of the Earth's rotation. GMT is so irrelevant for GPS, which uses atomic time (one version of it is the UTC).

For those California numbers (Northern: 767-XXXX, Southern: 853-1212), it's only good if you get AT&T (formerly SBC, formerly Pacific Bell). If you live in Verizon (formerly GTE) territory, its version is no good. Calls from out of the area get connected to AT&T.
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