Actually, while it's equipotential with respect to altitude, it's not equipotential with respect to total energy. Don't forget objects at the equator, include the surface of the ocean, is travelling about 1,000 mph faster, Eastward, than the poles. This is rocket launches take place in more Southern regions.Originally Posted by kilopi
As for the rest of the article on Pioneer 10, couldn't tell you.
Are there radios of two frequencies, though? Different freqs are slowed down by interferring medium (gas/dust) at different rates. This is one means GPS uses to detect/adjust for ionosphere abberations. If P-10 had two radios, sending a ping on both and measuring the different times we received it might tell us not only redshift, but actual distance, as well as the density of the medium through which it's travelled.
But I'm sure the rocket scientists have thought of this!