- #1
Cane_Toad
- 142
- 0
Two questions:
I saw a TV program recently which had an explanation for the first measurement of the speed of light, and it bothered me until I started looking it up (via Google...) I've now seen several instances agreeing with the TV guy saying that Roemer noticed that the observed revolution time of a moon of Jupiter varied according to whether Jupiter is near or far.
This is wrong, right? The revolution time depends on whether the distance is increasing or decreasing, and is the same when Jupiter is at the closest and farthest points. If this is true, then how does a bozo get on the science channel saying the former (Ok, ok. I don't really need an answer to this..)?
Secondly, the speed of light was calculated using the Earth's revolution speed as known at the time. Since that was 1676, I have no real idea whether the error (220,000 km/s, versus 300,000 km/s) was due to the inaccuracy of the observation times, or the value of the Earth's revolution time, or the absence of the revolution time of Jupiter in the calculation (which seemed a possible oversight in what I've read so far), or something else.
[As usual, please excuse my mediocre understanding of the subject matter.]
I saw a TV program recently which had an explanation for the first measurement of the speed of light, and it bothered me until I started looking it up (via Google...) I've now seen several instances agreeing with the TV guy saying that Roemer noticed that the observed revolution time of a moon of Jupiter varied according to whether Jupiter is near or far.
This is wrong, right? The revolution time depends on whether the distance is increasing or decreasing, and is the same when Jupiter is at the closest and farthest points. If this is true, then how does a bozo get on the science channel saying the former (Ok, ok. I don't really need an answer to this..)?
Secondly, the speed of light was calculated using the Earth's revolution speed as known at the time. Since that was 1676, I have no real idea whether the error (220,000 km/s, versus 300,000 km/s) was due to the inaccuracy of the observation times, or the value of the Earth's revolution time, or the absence of the revolution time of Jupiter in the calculation (which seemed a possible oversight in what I've read so far), or something else.
[As usual, please excuse my mediocre understanding of the subject matter.]