CHINESE SPACE LAUNCH: China's Shenzhou 7 spacecraft carrying a 3-man crew lifted off today from the Jiuquan Satellite Launch Center and is now in Earth orbit. During the upcoming three-day mission, Chinese astronauts, called taikonauts, will launch a small satellite and conduct their country's first spacewalk. Shenzhou 7 and the body of the rocket that launched it will be visible to the naked eye as they orbit Earth. Check the Satellite Tracker for viewing times.
Sighting report: Shortly after launch, Shenzhou 7 and its rocket passed over Wainuiomata, New Zealand, where Robert Holdsworth saw them. "They went just below Orion with only about a second or so between them." Both were about as bright as first magnitude stars, he says.
LOW SOLAR WIND: The solar wind is losing power. That's the surprising conclusion of scientists working with data from the Ulysses spacecraft, which has been circling the sun in a polar orbit for nearly 20 years. During that time solar wind pressure has dropped more than 20%. Note the blue curve in the "clock plot" below:
Blue traces solar wind pressure now. For comparison, green traces the significantly higher pressure of the mid-1990s. How this difference fits into the big picture of solar activity over the centuries, no one knows, because solar wind measurements began only 50 years ago with the start of the Space Age. Early measurements were spotty and not always well-calibrated, so, in fact, we know the solar wind well for even less than 50 years. Consequences of low solar wind include fewer geomagnetic storms, more cosmic rays, and NASA's Voyager spacecraft exiting the solar system sooner than anyone expected. Get the full story from Science@NASA.
SUNRISE AT THE SOUTH POLE: On Sept. 21st, Ethan Dicks looked out the window of his office and saw the sun for the first time in 6 months. He quickly grabbed his camera and snapped this picture of sunrise at the South Pole:
"I am a researcher for the University of Wisconsin-Madison, running
IceCube, the large (1 km3 when completed) neutrino telescope that's under construction a mile below the ice near the South Pole," explains Dicks. "The past six months have been almost nothing but night; it's good to see the sun again."
He took the picture a full day before the Sept. 22nd equinox--the "official" date of sunrise. Geometrically, the sun should've been mostly below the horizon at the time, but refraction by the dense polar atmosphere lifted the image up for all to see.
"Polar regions are famous for mirages and early explorers sometimes wondered what was real and what illusion," notes atmospheric optics expert Les Cowley. "In Dicks' picture, several air layers of different temperature have distorted and sliced the sun. Its rays are bent as they pass between the layers to form multiple images, some inverted and some upright."
Dicks is a veteran observer of South Pole sunrises. "This is my third winter here," he says. Some sunrises are heralded weeks ahead of time by a diffuse glow on one side of the sky and the retreating shadow of Earth ("a dark blue band topped by a fringe of magenta") on the other. Eventually a sliver of sun appears, circling the horizon for days, growing in size, until finally the sun emerges in full. "When it's clear, the show is amazing. This year, we were mostly clouded out until Sept. 21st. I feel bad for folks on their first and maybe only winter-over; they missed the full sunrise."
When you're at the South Pole, though, even a fraction of sunrise can be a wonderous thing.
SOLAR WIND LOSING POWER: In a briefing yesterday at NASA HQ, solar physicists announced that the solar wind is losing pressure, hitting a 50-year record low for the Space Age. This development has repercussions across the solar system: full story.
Sept. 2008 Aurora Gallery
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