Dear kallog,
This experiment is that at the same time people in Japan and China also sends electromagnetic waves to pass to each other via geostationary satellites. It was found that electromagnetic waves to reach Japan from China about 90ns faster than from the opposite direction.It is considered a result of Saganac effect of the Earth's rotation.
However, the Earth is also revolution. Why can not people find the Sagnac effect caused by revolution?
Someone stated that the angular velocity of earth rotation(ω1＝15rad·h-1) was much larger than that of earth revolution (ω2＝0.04rad·h-1), therefore the Sagnac effect produced by Earth revolution was so much smaller than that produced by Earth rotation to measure. This interpretation was lacking rigorous consideration. We know that Sagnac effect value is
Δt = 2vL / (c^2-v^2 )
where L is the length of circular arc between two points, v is linear velocity ( v = ωR ), ω is angular velocity, and R is radius. It seems that Sagnac effect value Δt is proportional to angular velocity ω , but it should be paid special attention to the fact that it is also proportional to radius R . Although the angular velocity of earth revolution was much less than that of earth rotation, the earth revolution’s radius R was much less than earth rotation’s radius r . Sagnac effect value Δt is proportional to the product of angular velocity ω and radius R , named linear velocity. The linear velocity of earth revolution (30km·s-1) was much larger than that of earth rotation (0.46km·s-1), whereas the length ( L ) of circular arc between two points (distance between China and Japan) was invariant so that the Sagnac effect produced by earth revolution was much larger than that produced by earth rotation.
Best Regards
Xinwei Huang
