NASA’s five THEMIS spacecraft have discovered a breach in Earth’s magnetic field ten times larger than anything previously thought to exist. The size of the opening and the strange way it forms could overturn long-held ideas of space physics.

“At first I didn’t believe it,” says THEMIS project scientist David Sibeck of the Goddard Space Flight Center. “This finding fundamentally alters our understanding of the solar wind-magnetosphere interaction.”

The magnetosphere is a bubble of magnetism that surrounds Earth and protects us from solar wind. Exploring the bubble is a key goal of the THEMIS mission, launched in February 2007. The big discovery came on June 3, 2007, when the five probes serendipitously flew through the breach just as it was opening. Onboard sensors recorded a torrent of solar wind particles streaming into the magnetosphere, signaling an event of unexpected size and importance.

“The opening was huge—four times wider than Earth itself,” says Wenhui Li, a space physicist at the University of New Hampshire who has been analyzing the data. Li’s colleague Jimmy Raeder, also of New Hampshire, says “1027 particles per second were flowing into the magnetosphere—that’s a 1 followed by 27 zeros. This kind of influx is an order of magnitude greater than what we thought was possible.”

 

Source: Nasa Science – click here for full article

 

 

 

From humble beginnings in a Utah beryllium mine to the most advanced laboratories in the world, the mirrors of NASA’s next great observatory are taking an incredible journey to space.

December 10, 2008: The James Webb Space Telescope, targeted for launch in 2013, is already taking an incredible journey right here on Earth. It’s zigzagging up, down, and across the US to be “spit and polished” to perfection for its lofty space mission.

“To find the first stars and galaxies that formed in the early universe, which are millions and even billions of light years away, the Webb telescope mirror has to be wickedly smooth,” says Jeff Kegley of NASA’s Marshall Space Flight Center.

To get ready for space, the 18 mirror segments that will ultimately form the Webb telescope’s huge primary mirror are trucked from pit stop to pit stop in tandem cross-country for careful processing and polishing. They visit seven different states, some several times.

During the long odyssey, every precaution is taken for their protection. How many years of bad luck would you have if you broke one of these mirrors?

“That’s something we don’t talk about,” laughs Helen Cole, also of Marshall. “But seriously, we do have three spare segments, so no problem there.”

Let’s trace a mirror segment’s Earthly journey from rough start to “wickedly smooth,” and finally to union with its 17 siblings to form a 6.5 meter (21 ½ foot) wide whole with a total area of 25 square-meters (almost 30 square yards).

Source: Nasa Science – click here for full article

 

 

 

Astronomers from NASA and Caltech are predicting a near-storm of Leonids in 2009 based on a surprising outburst of meteors just two weeks ago.

Dec. 4, 2008: Astronomers from Caltech and NASA say a strong shower of Leonid meteors is coming in 2009. Their prediction follows an outburst on Nov. 17, 2008, that broke several years of “Leonid quiet” and heralds even more intense activity next November.

“On Nov. 17, 2009, we expect the Leonids to produce upwards of 500 meteors per hour,” says Bill Cooke of the NASA Marshall Space Flight Center. “That’s a very strong display.”

Forecasters define a meteor storm as 1000 or more meteors per hour. That would make the 2009 Leonids “a half-storm,” says Jeremie Vaubaillon of Caltech, who successfully predicted a related outburst just a few weeks ago.

On Nov. 17, 2008, Earth passed through a stream of debris from comet 55P/Tempel-Tuttle. The gritty, dusty debris stream was laid down by the Leonids’ parent comet more than five hundred years ago in 1466. Almost no one expected the old stream to produce a very strong shower, but it did. Observers in Asia and Europe counted as many as 100 meteors per hour.

 

Source: Nasa Science – click here for full article