1,215 reputation
722
bio website dotancohen.com
location
age 37
visits member for 3 years, 2 months
seen yesterday

Jun
26
asked Why is the Pegasus launched from a subsonic airplane?
Jun
6
comment Might a planet perform figure-8 orbits around two stars?
Thank you, the illustration makes it clear exactly why this system is unstable.
Apr
23
awarded  Popular Question
Apr
15
accepted Other than the motion of the Earth, what else would cause parallax?
Apr
15
comment Other than the motion of the Earth, what else would cause parallax?
Right. Thank you!
Apr
15
comment Other than the motion of the Earth, what else would cause parallax?
I see, thanks. Therefore Bradley's discovery of aberration was the final bit of needed evidence?
Apr
15
comment Other than the motion of the Earth, what else would cause parallax?
Thank you for the very informative answer. You do discuss why aberration is easier to detect than parallax, which answers another (unasked) question of mine, but the core question is not addressed: Why was Bradley trying to measure parallax if it had not been discovered yet? And if it had been discovered (or suspected), yet the Earth was supposedly stationary (because Bradley's discovery proved that it wasn't), then what would explain the parallax?
Apr
2
accepted How is celestial navigation done on a low-level?
Mar
22
comment How is celestial navigation done on a low-level?
Thank you. The Apollo podcast is very informative.
Mar
22
asked How is celestial navigation done on a low-level?
Mar
22
awarded  Popular Question
Jan
4
awarded  Tumbleweed
Dec
26
asked Other than the motion of the Earth, what else would cause parallax?
Dec
17
awarded  Nice Question
Dec
12
comment Blue-shifting as opposed to violet-shifting
Thanks, Alan, this is a terrific answer. It doesn't address the question (relativistic blue-shifting), so I won't mark it as accepted, but it is extremely well-written and well-researched. This was fun to read! Thank you!
Dec
11
comment Blue-shifting as opposed to violet-shifting
Nice, thanks! This addresses the red herring, not the question, but it is a very concise way to address the colours of the sky. I wonder why we don't see the sky green, though, as green is no less dominant on the graph and our eyes are very sensitive to green.
Dec
11
comment Blue-shifting as opposed to violet-shifting
@Kitchi: So I guess an ultraviolet source would be shifted away from the blue, yet be erroneously called blueshifted.
Dec
11
asked Blue-shifting as opposed to violet-shifting
Nov
28
comment How distorted does the Andromeda Galaxy appear to us due to the speed of light?
Thanks, Martin.
Nov
28
accepted How distorted does the Andromeda Galaxy appear to us due to the speed of light?