William Atkins
Friday, 16 October 2009 20:34
Science -
Space
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THE NASA spacecraft IBEX is making a map of the edge of the heliosphere, the magnetic boundary formed by the solar wind and interstellar matter at the edge of the solar system. Unexpectedly, IBEX imaged a "bright, winding ribbon of unknown origin" that goes about 80% away around the solar system.
THE NASA spacecraft
IBEX is making a comprehensive map of the heliosphere, the magnetic boundary formed by the solar wind at the edge of the solar system--around 75 to 90 astronomical units (AU) from the Sun (where one AU is the mean distance between the Sun and Earth).
Unexpectedly, the IBEX spacecraft imaged a
“bright, winding ribbon of unknown origin” that goes about 80% around the solar system
At the termination shock, where the solar wind begins to slow down (from supersonic to subsonic speeds, or from above the speed of sound to below the speed of sound) from its journey from the Sun, this strange-looking ribbon appeared to the IBEX spacecraft.
Astronomers wonder: What is it?
The NASA Interstellar Boundary Explorer (IBEX) discovered this ribbon while making the first ever map of the heliosphere. Learn more about the Sun’s magnetic bubble at the NASA website “
The Heliosphere.”
IBEX was launched on October 19, 2008, at 17:47:23 GMT, from Kwajalein Atoll in the South Pacific. It is in a highly eccentric, elliptical orbit about Earth.
Its orbital perigee (closest point to Earth) is about 5,000 kilometers (3,100 miles) from Earth, while its orbital apogee (furthest point from Earth) is approximately 250,000 to 300,000 kilometers (160,000 to 190,000 miles) from Earth.
Its apogee takes it about three-fourth the way to the Moon.
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