Tuesday, April 12, 2011

Solar System's "Nose" Found

A NASA spacecraft has uncovered the solar system's "nose," which points in the direction our sun is moving through the Milky Way galaxy, astronomers say. The finding is based on newly released data from the Interstellar Boundary Explorer satellite (IBEX), an Earth-orbiting probe that has been mapping the solar system's outer frontier since 2008. As the sun travels through the galaxy, the solar wind—actually charged particles streaming from the sun—collides with interstellar gases, forming a cocoon around the solar system called the heliosphere. The edge of this cocoon, the heliopause, lies more than 9 billion miles from the sun.

Cosmic rays constantly bombard our solar system, but the heliosphere shields us from most of the radiation. Still, the small amounts that leak through and reach Earth can fry satellite electronics and pose a health hazard for astronauts. In 2009 IBEX revealed a vast ribbon of atoms snaking its way along the solar system's edge. While intriguing, this ribbon was preventing astronomers from mapping the entire heliosphere. Now Schwadron and his team have finally been able to digitally subtract the intense emissions given off by this mysterious ribbon, revealing the heliosphere's nose. This feature, like the bow of a ship, appears at the leading edge of the windsock-like heliosphere.

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