Conveniently, more modern spacecraft than the Pioneers include separate range-finding hardware, which can be used to test the accuracy of the Doppler method.

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If you are willing to pay, the options range from finding those must-have gifts to cooking a Christmas meal.

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Keys enjoyed an impressive third quarter, Kelly crashing over to complete a fast-flowing handling move, and with Bai finding his range with the boot, Cardiff couldn't relax.

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For those who really want to keep track of their socks, the app also produces a range of data - checking how black they are, offering to replace worn-out socks and even finding a close match for socks whose partners have gone astray.

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