I don't know the answer to either of those but am wondering if the answer to (2) might be Eratosthenes in his work on calculating the circumference of the Earth? In which case, the how would be by noting that the sun was directly overhead in his home city at the same time as it was at such-and-such an angle in another city a few hundred miles or so away.
Of course, I might just be barking up the wrong tree.
Archimedes would be the fall-back answer.
Completely correct, J360!In doing so - around BC 240! - he determined the circumference of the Earth to be 25,000 miles, quite close to the modern measurement of 24,902 miles.As for Part #1:
Very Long Baseline Interferometry (VLBI), acts as a kind of GPS for Earth. To deduce Earth’s orientation in space, and the small variations in the Earth’s rate of rotation, ground stations spread across the globe observe dozens of quasars, which are distant enough to be stable reference points.
“VLBI is the one technique that connects measurements made on Earth to the celestial reference frame—that is, the rest of the universe,” says Stephen Merkowitz, who is the project manager for NASA’s space geodesy initiative.
The key is the painstakingly accurate timing of when the quasar signals arrive. “With this information, we can determine the geometry of the stations that made the observations,” says Chopo Ma, head of the VLBI program at Goddard.
By knowing the geometry, researchers aim to measure the distances between the ground stations down to the millimeter, or about the thickness of a penny.
