* Astronomy

Carnegie Institution researchers say that Plate tectonics the geological process responsible for creating the Earths continents, mountain ranges, and ocean basins may have stopped at least once in the planets history, and that it may happen again.
A key aspect of plate tectonic theory is that on geologic time scales ocean basins are transient features, opening and closing as plates shift. Basins are consumed by a process called subduction, where oceanic plates descend into the Earths mantle.
Subduction zones are the sites of oceanic trenches, high earthquake activity, and most of the worlds major volcanoes.
Paul Silver of the Carnegie Institutions Department of Terrestrial Magnetism and former postdoctoral fellow Mark Behn say that most of the subduction zones are currently located in the Pacific Ocean basin.
Writing in the journal Science, they revealed that the Pacific basin may close in about 350 million years, when the westward-moving Americas collide with Eurasia.
Silver and Behn believe that that most of the planets subduction zones will disappear at that moment, effectively stopping plate tectonics unless new subduction zones start up.

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Another year, another trip around the sun. Almost.
Earth hasn't quite completed the lap it started on Jan. 1, 2007. There are still a little more than 400,000 miles to travel before the planet makes a complete orbit around the sun.
And the 2007 mark is 400,000 miles shy of where it began in 2006, which is 400,000 miles short of the 2005 starting line.

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Magnetic anomaly map of the world
This map is the first global compilation of the wealth of magnetic anomaly information derived from more than 50 years of aeromagnetic surveys over land areas, research vessel magnetometer traverses at sea, and observations from earth-orbiting satellites, supplemented by anomaly values derived from oceanic crustal ages.
The objective is to provide an interpretive dimension to surface observations of the Earths composition and geologic structure. Metamorphism, petrology, and redox state all have important effects on the magnetism of crustal materials.


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The first global map of magnetic peculiarities - or anomalies - on Earth has been assembled by an international team of researchers.
Magnetic anomalies are caused by differences in the magnetisation of the rocks in the Earth's crust.
Many years of negotiation were required to obtain confidential data from governments and institutes.
Scientists hope to use the map to learn more about the geological composition of our planet.
The World Digital Magnetic Anomaly Map (WDMAM) is available through the Commission for the Geological Map of the World.


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Credit Korhonen, J.V., Fairhead, J.D., Hamoudi, M., Hemant, K., Lesur, V., Mandea, M., Maus, S., Purucker, M., Ravat, D., Sazonova, T.,and Thebault, E., 2007, Magnetic Anomaly Map of the World (and associated DVD), Scale: 1:50,000,000, 1st edition, Commission for the Geological Map of the World, Paris, France.

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