swansont Posted April 21, 2010 Share Posted April 21, 2010 Light takes about .13 seconds to go around the earth. agreed In that time the earth moves about 0.06 km This is where you are going wrong. We are measuring the sagnac effect for a path from A to B on the earth. So, light is not going around the earth. It is going from A to B. Say that distance is 10 km. You will find the sagnac correction higher for the orbit vs the rotation. It is not about now long light takes to move around the circumference. It is about how far light moves while the earth moves. It's about both. If light goes from A to B along the equator you have to know how long it took and how far the point on the earth moved (relative to an inertial reference) in that time. If B represent a point half way around the world, then it's 0.065 seconds, and the earth moves 0.03 km and the Sagnac is 100 ns. If they are 10,000 km apart, then it's 50 ns. If they are 10 km apart, it's 50 ps. Link to comment Share on other sites More sharing options...
vuquta Posted April 21, 2010 Author Share Posted April 21, 2010 It's about both. If light goes from A to B along the equator you have to know how long it took and how far the point on the earth moved (relative to an inertial reference) in that time. If B represent a point half way around the world, then it's 0.065 seconds, and the earth moves 0.03 km and the Sagnac is 100 ns. If they are 10,000 km apart, then it's 50 ns. If they are 10 km apart, it's 50 ps. This is what I get for the rotation sagnac. I am still not able to figure out the earth's orbital sagnac. I cannot make it work any way I go about it. Link to comment Share on other sites More sharing options...
swansont Posted April 21, 2010 Share Posted April 21, 2010 I figured it a few posts back. It'll be about a third of a nanosecond for 10,000 km. Link to comment Share on other sites More sharing options...
vuquta Posted April 21, 2010 Author Share Posted April 21, 2010 I figured it a few posts back. It'll be about a third of a nanosecond for 10,000 km. I'll look at it again. Merged post follows: Consecutive posts mergedI figured it a few posts back. It'll be about a third of a nanosecond for 10,000 km. This is the post your mean. http://www.scienceforums.net/forum/showpost.php?p=559741&postcount=99 I have already addressed this and proven it wrong. Link to comment Share on other sites More sharing options...
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