AURORA ALERTS: Did you miss the Northern Lights of June 25th? Next time get a wake-up call from Space Weather PHONE. | | | SOLAR SAIL: This summer, NASA engineers will try to realize a dream older than the Space Age itself--the deployment of a working solar sail in Earth orbit. NanoSail-D is scheduled for launch onboard a SpaceX Falcon 1 rocket on July 29, 2008: full story. LAVENDER SUN: California is on fire. Hundreds of wildfires across the state are filling the air with smoke and filling the sky with ... lavender suns? That's what photographer Christopher Calubaquib saw when he looked through the haze over El Sobrante, California, on June 26th: Yes, smoke can turn the sun shades of blue. It happens when the air is filled with particles measuring about 1 micron (10-6 m) across, a little larger than the wavelength of red light. Micron-sized particles scatter red light strongly, while letting blue light pass through. The mix of ash over El Sobrante produced a lavender hue, reminiscent of the great Alberta muskeg fires of September 1950. Believe it or not, the same physics can turn the Moon blue, but that is another story. Is the smoke wafting through your hometown this weekend? Be alert for the lavender sun. MARTIAN SOLSTICE: On Earth, northern summer began on June 20th. On Mars, the same thing happened five days later. Phoenix's stereo camera snapped this picture of its own shadow on June 25th, the date of the martian summer solstice: The solstice brought maximum temperatures of -24 F (-32 C) to Phoenix's arctic landing site. Why so cold? Mars is 48 million miles farther from the sun than Earth and the thin atmosphere of Mars traps precious little heat. Temperatures rarely rise above the freezing point of water. No wonder there is so much ice in the soil. Right now, Phoenix's robotic arm is busy rasping a layer of ice found in the Snow White trench just out of view of the picture, above. When samples are delivered to Phoenix's internal chemistry lab, researchers on Earth may be able to tell if this ice was liquid during past, warmer climate cycles. A positive result would be significant because the soil at Phoenix's feet is chocked with so many nutrients, "you could grow asparagus in it," according to one mission scientist. Evidence is mounting, on a chill summer day, that the stuff of life exists on Mars. FORGOTTEN ROVER: (3D glasses required) "While Phoenix is busy tasting marsdust, his more mobile friend Opportunity is having a closer look at the amazing cliffs of Victoria crater," notes Belgian graphic artist Patrick Vantuyne. Combining images from Opportunity's stereo camera, Vantuyne created a dramatic three dimensional view of the rover's surroundings. Click here for 3D. June 2008 Aurora Gallery [Aurora Alerts] [Night-sky Cameras] |