Measurements from very long distance...

Thread Starter

Externet

Joined Nov 29, 2005
1,410
Do you think it is possible to measure if an object is 1 milimetre closer than other; from 200+ Km away ?
 

WBahn

Joined Mar 31, 2012
24,692
Do you think it is possible to measure if an object is 1 milimetre closer than other; from 200+ Km away ?
You need to be a lot more specific. Are these two objects next to each other? How big are these object? What part of the object is the measurement to be taken at? Are they static? Are they on the ground? Is there clear line of sight to the objects? Are you willing to spend a few million dollars to make the measurement? Is this just a wild thought thrown out or do you have a specific application in mind?
 

atferrari

Joined Jan 6, 2004
3,451
Do you think it is possible to measure if an object is 1 milimetre closer than other; from 200+ Km away ?
From what I learnt from someone trained by Wild, measurements could be done in situ, so to speak, and then, the resulting values, sent to you. Othertwise, TOF should count.
 

BR-549

Joined Sep 22, 2013
4,936
A 1 millimeter change in distance will make about 3.3 or 3.4 picoseconds difference in EM travel time.

And times two for the bounce. A picosecond counter is required.

"1 picosecond – time taken by light in a vacuum to travel approximately 0.30 mm."
 
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