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Gravity anomalies
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The April issue of the respected scientific journal Physics Today features a full-page global map of gravity anomalies produced by Dr. Ole Andersen and his colleagues at the National Space Institute at the Technical University of Denmark.
The global gravitational map is freely available at the website of the National Space Institute.

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RE: The Earth
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This GSA Special Paper focuses on the catastrophic events that have influenced both Mars and Earth and is part of the ongoing search for the correct balance between catastrophic and uniformitarian processes. The book aims to "expand the geoscience horizons" of a wide range of readers by examining evidence for various geologic catastrophes on both Earth and Mars, their preservation on Earth as compared to Mars, and how these events may have influenced Earths evolution.
Catastrophic events discussed in this volume include impact cratering, megafloods, megascale eruptions, sub-ice volcanism on Earth, and natural disasters and human behavior.

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Researchers from the University of Melbourne and Princeton University have shown for the first time that the difference in reflection of light from the Earth's land masses and oceans can be seen on the dark side of the moon, a phenomenon known as earthshine.
The paper is published in this week's edition of the international journal Astrobiology.

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Breathing Cycles in Earth's Upper Atmosphere Linked to Solar Wind Disturbances
A new University of Colorado at Boulder study shows the periodic "breathing" of Earth's upper atmosphere that has long puzzled scientists is due in part to cyclic solar wind disturbances, a finding that should help engineers track satellites more accurately and improve forecasts for electronic communication disruptions.
Aerospace engineering sciences department Associate Professor Jeff Thayer said the outer, gaseous shell of the atmosphere, known as the thermosphere, is known to expand and contract as it exchanges energy with the space environment, causing changes in thermosphere density. Changes in thermosphere density can alter the atmospheric drag of satellites, causing them to deviate from their predicted paths and complicating tracking and orbital adjustment manoeuvres.
While extreme ultraviolet radiation from the sun is the dominant mechanism that causes the thermosphere to "breathe," the new CU-Boulder study indicates high-speed wind from the sun triggers independent breathing episodes by creating geomagnetic disturbances, heating the thermosphere and altering its density. The wind streams are generated by relatively cool pockets on the sun's surface known as solar coronal holes that periodically rotate around the sun's surface.

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Space Has Never Been Closer
Observations made by NASA instruments onboard an Air Force satellite have shown that the boundary between the Earth's upper atmosphere and space has moved to extraordinarily low altitudes. These observations were made by the Coupled Ion Neutral Dynamics Investigation (CINDI) instrument suite, which was launched aboard the U.S. Air Force's Communication/Navigation Outage Forecast System (C/NOFS) satellite on April 16, 2008.
The CINDI suite, which was built under the direction Principal Investigator Rod Heelis of the University of Texas at Dallas, includes both ion and neutral sensors and makes measurements of the variations in neutral and ion densities and drifts.
CINDI and C/NOFS were designed to study disturbances in Earth's ionosphere that can result in a disruption of navigation and communication signals. The ionosphere is a gaseous envelope of electrically charged particles that surrounds our planet and it is important because Radar, radio waves, and global positioning system signals can be disrupted by ionospheric disturbances.
CINDI's first discovery was, however, that the ionosphere was not where it had been expected to be. During the first months of CINDI operations the transition between the ionosphere and space was found to be at about 420 km altitude during the nighttime, barely rising above 800 km during the day. These altitudes were extraordinarily low compared with the more typical values of 640 km during the nighttime and 960 km during the day.
The height of the ionosphere/space transition is controlled in part by the amount of extreme ultraviolet energy emitted by the Sun and a somewhat contracted ionosphere could have been expected because C/NOFS was launched during a minimum in the 11-year cycle of solar activity. However, the size of the actual contraction caught investigators by surprise. In fact, when they looked back over records of solar activity, they found that C/NOFS had been launched during the quietest solar minimum since the space age began.
This extraordinary circumstance is providing an unparalleled opportunity to study the connection between the interior dynamics of the Sun and the response of the Earth's space environment.

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What Makes Our World So Special?
We live on a blue planet. Seventy percent of the surface is covered in water, and many life forms have similar high water proportions in their tissues. Water itself has some unusual qualities. It is one of the lightest in gaseous phase, very dense in liquid form, and the cohesiveness of water molecules means the compound has an unexpectedly high boiling point and unexpectedly high freezing point.

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Earth and its mysteries in a click
What does occurs at the center of our planet? Can one envisage the earthquakes and their effects? How to consider the seismic risks?
Many will find answers to their questions online at their visit of the new virtual CNRS.
In a helpful way, nearly 60 researchers of the Laboratory of internal and tectonophysic geophysics publish to it, in images, their work with the daily newspaper. In particular, you can listen to the sounds of  volcanoes and will surprisingly discover that seismology helps with the study of the pyramid of Kheops.

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Cataclysmic volcanism
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The ancient Earth experienced bouts of cataclysmic volcanism that buried much of its surface in up to 15 kilometres of lava, says a new study.
The research from the Australian National University, in Canberra, reveals that these hellish episodes of volcanic activity each lasted for around one million years - but the last ended around three billion years ago, and the phenomenon is unlikely to occur again.
Study author Geoff Davies used computer models of the Earth's deep interior which revealed that for much of its early history, the planet's innards were a ticking time bomb.

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Plate tectonics
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A new picture of the early Earth is emerging, including the surprising finding that plate tectonics may have started more than 4 billion years ago much earlier than scientists had believed, according to new research by UCLA geochemists reported Nov. 27 in the journal Nature.
 
"We are proposing that there was plate-tectonic activity in the first 500 million years of Earth's history. We are reporting the first evidence of this phenomenon. Unlike the longstanding myth of a hellish, dry, desolate early Earth with no continents, it looks like as soon as the Earth formed, it fell into the same dynamic regime that continues today. Plate tectonics was inevitable, life was inevitable. In the early Earth, there appear to have been oceans; there could have been life completely contradictory to the cartoonish story we had been telling ourselves" - geochemistry professor Mark Harrison, director of UCLA's Institute of Geophysics and Planetary Physics and co-author of the Nature paper.

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