Sunday, 11 November 2012

The Washington Double Star Catalog

Astrometry Department, U.S. Naval Observatory
3450 Massachusetts Ave, NW, Washington, DC 20392

The Washington Double Star Catalog (WDS) maintained by the United States Naval Observatory is the world's principal database of astrometric double and multiple star information. The WDS Catalog contains positions (J2000), discoverer designations, epochs, position angles, separations, magnitudes, spectral types, proper motions, and, when available, Durchmusterung numbers and notes for the components of 103,861 systems based on 750,563 means.

Global Warming Cause Felt by Satellites and Space Junk

An artist's illustration of the Canadian Space Agency's SCISAT-1 satellite in orbit, which is carrying the Atmospheric Chemistry Experiment to track carbon dioxide levels in Earth's atmosphere.
CREDIT: Canadian Space Agency

Rising carbon dioxide levels at the edge of space are apparently reducing the pull that Earth's atmosphere has on satellites and space junk, researchers say.
The findings suggest that manmade increases in carbon dioxide might be having effects on the Earth that are larger than expected, scientists added.

In the layers of atmosphere closest to Earth, carbon dioxide is a greenhouse gas, trapping heat from the sun. Rising levels of carbon dioxide due to human activity are leading to global warming of Earth's surface.


Source: www,

Total Solar Eclipse of 2012 November 13/14

On 2012 November 13/14, a total eclipse of the Sun is visible from within a narrow corridor that traverses Earth's southern Hemisphere. The path of the Moon's umbral shadow begins in northern Australia and crosses the South Pacific Ocean with on other no landfall. The Moon's penumbral shadow produces a partial eclipse visible from a much larger region covering Australia, New Zealand, and the South Pacific.

For those traveling to Australia for the eclipse, please note that the eclipse occurs on the morning of Nov. 14 local time.

Read more....

Source: Nasa

The Van Allen Probes: Honoring the Origins of Magnetospheric Science

A broad suite of instruments on the Van Allen Probes will help scientists understand more about the myriad types of particles and waves in the radiation belts that encircle Earth, providing a flood of new data for scientists who study the magnetosphere. Credit: NASA/Goddard Space Flight Center.

Earth's magnetism has captured human attention since the first innovator noticed that a freely moving piece of magnetized iron would always align itself with Earth's poles. Throughout most of history, the origins and physics of this magnetism remained mysterious, though by the 20th century certain things had been learned by measuring the magnetic field at Earth's surface. These measurements suggested that Earth's magnetic field was consistent with that of a giant bar magnet embedded deep inside Earth. However, the magnetic field observed at the surface of our planet is constantly fluctuating. During the 1930s scientists pioneered explanations that such fluctuations were due to streams of particles from the sun striking and becoming entrapped within Earth’s magnetic field.

Truly understanding Earth's magnetic environment, however, required traveling to space. In 1958, the first US rocket -- known as Explorer 1 and led by James Van Allen at the University of Iowa -- was launched. By providing observations of a giant swath of magnetized radiation trapped around Earth, now known as the Van Allen Belts, Explorer 1 confirmed that Earth's magnetic environment, the magnetosphere, was not a simple place. We now know that it has a complex shape – compressed on the side facing the sun, but stretched out into a long tail trailing off away from the sun -- affected as much by incoming material from the sun as Earth's own intrinsic magnetism. This magnetic field constantly fluctuates in response to both internal instabilities and events on the sun. It also provides a home for a host of electrified particles spiraling through this complex system.