This photo was taken in December 1972 by the Apollo 17 crew. The spacecraft was traveling between the Earth and the Moon. The reddish landmass is Africa and Saudi Arabia which is desert. The white is both clouds and the ice covering Antarctica.
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Image courtesy of NASA/JPL
Earth--What a Drag!?!
News story originally written on April 1, 1998
The first evidence has been found that shows the Earth does drag quite a bit - it drags space and time around itself as it rotates! This drag effect was predicted 80 years ago using Einstein's
theory of general relativity.
Scientists found this evidence by using the LAGEOS I and LAGEOS II satellites. LAGEOS stands for Laser Geodynamics Satellite. One of the researchers, Dr. Erricos Pavlis remarked, "General relativity predicts that massive rotating objects should drag space-time around themselves as they rotate. Frame dragging is like what happens if a bowling ball spins in a thick fluid such as molasses. As the ball spins, it pulls the molasses around itself. Anything stuck in the molasses will also move around the ball. Similarly, as the Earth rotates, it pulls space-time in its vicinity around itself. This will shift the orbits of satellites near the Earth."
There is a lot of uncertainty involved in the research being done. So scientists want to launch the LAGEOS III satellite to check their measurements and make new ones.
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