3 ms·
This was really interesting to read, thank you. The "a satellite would orbit the hill" and " direction of "down" parts of the comment, in particular, really hel
by RHSeeger 7y ago
This was really interesting to read, thank you. The "a satellite would orbit the hill" and " direction of "down" parts of the comment, in particular, really helped understand/visualize what you were describing. Also, I immediately went into the next room and told my wife about it, because I thought it was that interesting. Thanks for chiming in.
- ISL 7y agoThanks -- it's so cool! (We care about this difference-in-the-direction-of-down because we need to lock one of our turntables to "local vertical" with nanoradian stability. It was initially a surprise, before my time, when it was realized that it was impossible to do so simultaneously for two sensors on the same turntable but at different locations on the turntable axis.) Also, if you think that's cool, depending on your latitude, the "down" you experience doesn't point in the direction of the center of the earth. The earth is rotating, so there is a substantial centrifugal contribution to the acceleration you experience. Off the top of my head, I believe the effect here in Seattle is about 14 milliradians. It is zero at the pole and equator (the apparent centrifugal acceleration makes you effectively lighter!), though :).
- deleted 7y ago[deleted]