Subscribe | UPI Odd Newsletter Subscribe THE GRAVITY OF THE SITUATION Gravity is not uniform over the Earth. There are hot spots and low spots and odd spots like Mystery Spots -- a Mystery Spot being a roadside attraction that claims a mysterious gravitational weirdness abounds in the confines of their perimeter fence. Normal gravity is apparently kept at bay outside said fence. Advertisement In any event, the accurate measurement of gravity seems to be related to density and thus can be an indicator of some geographic history. What's more, gravity maps have telltales regarding fault-lines, ice melt and other eco-systemic markers in the data. See wrgis.wr.usgs.gov/docs/gump/zulanger/bayarea/gravity_color.html for a gravity map of the San Francisco bay area. See antwrp.gsfc.nasa.gov/apod/ap011113.html for a global view. The color scale should be the same for both images and should tell you that gravity is rather lumpy as physical properties go. This distribution of gravity does mean that you are heavier in one location on Earth and lighter in another. The latest gizmos to go aloft are a couple of shop lamp-sized satellites that follow each other around the globe taking gravitation measurements. Their obit was designed to take advantage of the Earth's rotation and angle of inclination in such a way that the whole Earth is covered by their signals at one time or another. This is the GRACE satellite program. See essp.gsfc.nasa.gov/grace/ for all the technical details. Advertisement Send your ideas and comments to [email protected]
