World Sunlight Map Watch the sun rise and set all over the world on this real-time, computer-generated illustration of the earth's patterns of sunlight and darkness. The clouds are updated daily with current weather satellite imagery. The Mercator projection used here is one way of looking at the spherical earth as a flat map. Used since the 16th century for navigation, straight lines on this map can be used accurately as compass bearings but the size and shape of continents are distorted. Compare this with Peters, Mollweide or equirectangular projection maps. Also available is a semi-realistic view of dawn and dusk from far above the Earth, a look at the moon, and information about how this works.
Volcano Hazards Program STEM List of large volcanic eruptions in the 21st century This is a list of volcanic eruptions of the 21st century measuring a Volcanic Explosivity Index (VEI) of at least 4, as well as notable smaller eruptions. Note that the size of eruptions can be subject to considerable uncertainty. See also[edit] References[edit] External links[edit] Magnetic stripes and isotopic clocks [This Dynamic Earth, USGS] Oceanographic exploration in the 1950s led to a much better understanding of the ocean floor. Among the new findings was the discovery of zebra stripe-like magnetic patterns for the rocks of the ocean floor. These patterns were unlike any seen for continental rocks. Obviously, the ocean floor had a story to tell, but what? In 1962, scientists of the U.S. An observed magnetic profile (blue) for the ocean floor across the East Pacific Rise is matched quite well by a calculated profile (red) based on the Earth's magnetic reversals for the past 4 million years and an assumed constant rate of movement of ocean floor away from a hypothetical spreading center (bottom). A team of U.S. Other commonly used isotopic clocks are based on radioactive decay of certain isotopes of the elements uranium, thorium, strontium, and rubidium. "Developing the theory"
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