Thursday, 14 February 2013

Van Allen radiation belt



The NASA Van Allen Probes mission will go further and gain scientific understanding (to the point of predictability) of how populations of relativistic electrons and ions in space form or change in response to changes in solar activity and the solar wind. NASA Institute for Advanced Concepts–funded studies have proposed magnetic scoops to collect antimatter that occurs naturally in the Van Allen belts of Earth, although it is estimated only about 10 micrograms of antiprotons exist in the entire belt.

The Van Allen Probes mission was successfully launched on August 30, 2012.[5] The primary mission is scheduled to last 2 years, with expendables expected to last for 4 years. NASA's Goddard Space Flight Center manages the overall Living with a Star program of which Van Allen Probes is a project, along with Solar Dynamics Observatory (SDO). The Applied Physics Laboratory is responsible for the overall implementation and instrument management for the Van Allen Probes.

Van Allen radiation belts do exist on other planets in the solar system, whenever a planet or moon has a magnetic field that is powerful enough to sustain a radiation belt. However, many of these radiation belts have been poorly mapped. The Voyager Program (namely Voyager 2) only nominally confirmed the existence of similar belts on Uranus and Neptune.

Friday, 10 August 2012

Van Allen radiation belt

The Van Allen radiation belt is a torus of energetic charged particles (plasma) around Earth, which is held in place by Earth's magnetic field. It is thought that most of the particles that form the belts come from solar wind, and other particles by cosmic rays.

It is named after its discoverer, James Van Allen, and is located in the inner region of the Earth's magnetosphere. It is split into two distinct belts, with energetic electrons forming the outer belt and a combination of protons and electrons forming the inner belts. In addition, the radiation belts contain lesser amounts of other nuclei, such as alpha particles. The belts pose a hazard to satellites, which must protect their sensitive components with adequate shielding if their orbit spends significant time in the radiation belts.

Tuesday, 16 August 2011

Flame-colored Tanager

The Flame-colored Tanager, Piranga bidentata, formerly known as the Stripe-backed Tanager, is a medium-sized American songbird. Formerly placed in the tanager family (Thraupidae), it and other members of its genus are now classified in the cardinal family (Cardinalidae).

The species's plumage and vocalizations are similar to other members of the cardinal family. A tropical passerine bird, the Flame-colored Tanager is found in the mountains of Mexico, and throughout Central America to northern Panama; it is occasionally seen in the United States in the mountains in the southeast corner of Arizona, the southwest of New Mexico and Sonora (the Madrean sky islands of the northern portion of the western Mexican mountain range, Sierra Madre Occidental), and also the southwest corner of Texas.