Friday, October 3, 2008

More Astronomy News about Saturn, Mars, and Solar Winds

Saturn magnetizes its moon Titan (from New Scientist)
After 31 close fly-bys of the moon, the Cassini spacecraft finally flew through Titan's upper atmosphere at a time when the moon had edged out of the influence of Saturn's magnetic field.
The encounter, which took place on 13 June 2007, showed that Titan's atmosphere actually retains a memory of the magnetic field of the plasma that surrounds Saturn. This memory might last for as long as 3 hours.
"It's surprising that it stays there that long," says team member Andrew Coates of University College London. "Over long time scales, this could really help us understand how planetary atmospheres evolve."
Titan's temporary emergence fully exposes the moon to the solar wind. But the temporary magnetization of the moon's atmosphere, which produces a draped sheath of magnetic field lines, might protect it from substantial losses.

NASA Phoenix Lander Sees Falling Snow on Mars
NASA’s Phoenix Mars Lander has detected snow falling from Martian clouds. A laser instrument to gather data on how the surface and atmosphere interact, detected snow from clouds about 2.5 miles above the site where the Lander came to rest. The snow vaporized before reaching the ground, blasting hopes that we might get video of little Martian children making snowmen.

No ‘Solar Hurricanes’ Lately - Could Lack of Solar Winds Affect Us on Earth?
The Ulysses mission has discovered that the Sun has reduced its output of solar winds, bringing their level to the lowest ever since recording began. "The Sun’s 1.5 million km-per-hour solar wind inflates a protective bubble around the Solar System and can influence how things work here on Earth and even out at the boundary of our Solar System, where it meets the galaxy," said Dave McComas, Principal Investigator for the Ulysses solar wind instrument and senior Executive Director at the Southwest Research Institute in San Antonio, Texas. "Ulysses data indicate the solar wind’s global pressure is the lowest we have seen since the beginning of the space age."

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