I Speed of Light Measured by Jupiter's Moons: Error 26%?

[Sandeep T S]

Romer measured speed of light using moon's of Jupiter but he got value with a error of 26%. Is anyone did same experiment in modern era? And what value they got?

 

[Ibix]

Not that I'm aware of, although I haven't searched very hard. A former poster named Bartolomeo provided a reference to a 1970 analysis of Romer's work (see post #71 here) which I'm sure I've read online but can't currently find. It might have relevant citations. You might also want to look at the one-way speed of light section at in the experimental evidence for SR FAQ linked from a thread pinned at the top of this forum.

I'd be a little surprised if anyone has repeated it, however. Romer's work is a "one way" measurement of the speed of light, and therefore assumption dependent (not something he could have been aware of). We've got better ways of doing it these days.

 

[Sandeep T S]

Not that I'm aware of, although I haven't searched very hard. A former poster named Bartolomeo provided a reference to a 1970 analysis of Romer's work (see here) which I'm sure I've read online but can't currently find. It might have relevant citations. You might also want to look at the one-way speed of light section at in the experimental evidence for SR FAQ linked from a thread pinned at the top of this forum.

I'd be a little surprised if anyone has repeated it, however. Romer's work is a "one way" measurement of the speed of light, and therefore assumption dependent (not something he could have been aware of). We've got better ways of doing it these days.

I think we have some limitations to measure all variables for romer experiment so that make scientist to abandon this experiment.
I guess that if we measure all variables accurately, we get valve with 7-10% error. ( My guess)

I searched lot in online but I couldn't find anything more.

 

[Sandeep T S]

Not that I'm aware of, although I haven't searched very hard. A former poster named Bartolomeo provided a reference to a 1970 analysis of Romer's work (see post #71 here) which I'm sure I've read online but can't currently find. It might have relevant citations. You might also want to look at the one-way speed of light section at in the experimental evidence for SR FAQ linked from a thread pinned at the top of this forum.

I'd be a little surprised if anyone has repeated it, however. Romer's work is a "one way" measurement of the speed of light, and therefore assumption dependent (not something he could have been aware of). We've got better ways of doing it these days.

But I think romer experiment is only the one experiment which measure speed of light using time of flight.
And here source is moving one.

 

[Ibix]

I think we have some limitations to measure all variables for romer experiment so that make scientist to abandon this experiment.
I guess that if we measure all variables accurately, we get valve with 7-10% error. ( My guess)

We've made radar observations of the Galilean moons, so I suspect we could do better than your guess. The problem is that the answer depends on your choice of clock synchronisation procedure, so the result is assumption dependent.

I searched lot in online but I couldn't find anything more.

Did you look for the 1970 paper by Karlov?

But I think romer experiment is only the one experiment which measure speed of light using time of flight.

How would you measure speed apart from time of flight?

 

[Sandeep T S]

We've made radar observations of the Galilean moons, so I suspect we could do better than your guess. The problem is that the answer depends on your choice of clock synchronisation procedure, so the result is assumption dependent.
Did you look for the 1970 paper by Karlov?
How would you measure speed apart from time of flight?

I didn't got karlov's paper, could you share that?

Please also share reference of your first statement
(Radar observation). How could radar observation help our experiment?

 

[Ibix]

I didn't got karlov's paper, could you share that?

See the post linked in #2.

Please also share reference of your first statement
(Radar observation).

I just checked Wikipedia to see if it had been done - here. I note that it cites several references on radar ranging to the inner planets (which I knew about) but none to back up its claim of radar ranging of Jupiter or its moons, so I could be misleading you.

How could radar observation help our experiment?

Precise distances to the moons. Of course, this just ends up meaning that you are assuming your answer, but that's always going to be the case with a one-way measurement. If you are only interested in showing that Romer could have got smaller error bars, however, that's fine.