Saturday, October 17, 2009

Space Ribbon Dicsovery

In a discovery that took astronomers by surprise, the first full-sky map of the solar system's edge—more than 9 billion miles (15 billion kilometers) away—has revealed a bright "ribbon" of atoms called ENAs.

The solar system is surrounded by a protective "bubble" called the heliosphere.

The narrow ribbon snakes along this bubble's inner wall between Voyager 1 and 2, twin spacecraft that have been exploring the solar system's boundary since 2004 and 2007, respectively.

Voyager data, taken from specific regions within the boundary zone, had offered no hint that the ribbon existed. But from its orbit around Earth, NASA's Interstellar Boundary Explorer, or IBEX, spacecraft was able to give researchers a wider view.

IBEX team member Eric Christian, of NASA's Goddard Space Flight Center, compared the Voyager spacecraft to weather stations on Earth.

"Can you imagine trying to determine the weather of the entire Earth from two weather stations? You can't do it," Christian told reporters at a press conference this afternoon.

"IBEX is like our first weather satellite, and it gives us the full picture."

IBEX's map shows that the ribbon measures roughly two billion miles (three billion kilometers) long and several hundred thousand miles wide.

The ribbon isn't visible to people and wouldn't harm spacecraft or humans passing through it, IBEX principal investigator David McComas, of the Southwest Research Institute in Texas, told National Geographic News.

Astronomers aren't yet sure how the ribbon formed, but it's possible that the ribbon could be a result of pressure exerted on the heliosphere by our home galaxy's magnetic field.

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