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Does a giant crater lie beneath the Antarctic ice? Signs of an ancient impact could help to explain a mass extinction. Mark Peplow A dense bit of rock in the Antarctic (orange circle) seems to be circled by a crater. © Ohio State University Evidence of a cataclysmic meteorite impact has been unearthed in Antarctica, according to researchers who say the collision could possibly explain the greatest mass extinction ever seen on our planet. But scientists contacted by news@nature.com say they are sceptical, as no signs of such an enormous impact have been found in other, well-studied areas of Antarctica....

Explanation: Why do some places on Earth have higher gravity than others? Sometimes the reason is unknown. To help better understand the Earth's surface, sensitive measurments by the orbiting satellites GRACE and CHAMP were used to create a map of Earth's gravitational field. Since a center for studying this data is in Potsdam, Germany, and since the result makes the Earth look somewhat like a potato, the resulting geoid has been referred to as the Potsdam Gravity Potato. High areas on this map, colored red, indicate areas where gravity is slightly stronger than usual, while in blue areas gravity is...

Project Vanguard represented the American commitment to place a satellite in orbit as part of its contribution to the International Geophysical Year. The project was managed by the Naval Research Laboratory and funded by the National Science Foundation. Vanguard 1, known as TV-3 before launch, was to have been placed in orbit on December 6, 1957. The satellite was recovered after the launch rocket malfunctioned almost immediately after ignition and crashed on the launchpad. It carries two radio transmitters to allow earth stations to track its flight; this would allow scientists to obtain data on the Earth's shape and variations...