NASA 宇宙の記録
今日の天体写真 (APOD)= カレンダーから選ぶ「宇宙の神秘」=

Denizens of planet Earth watched last year's Perseid meteor shower by looking up into the bright moonlit night sky. But this remarkable view captured on August 13, 2011 by astronaut Ron Garan looks down on a Perseid meteor. From Garan's perspective onboard the International Space Station orbiting at an altitude of about 380 kilometers, the Perseid meteors streak below, swept up dust left from comet Swift-Tuttle heated to incandescence. The glowing comet dust grains are traveling at about 60 kilometers per second through the denser atmosphere around 100 kilometers above Earth's surface. In this case, the foreshortened meteor flash is right of frame center, below the curving limb of the Earth and a layer of greenish airglow, just below bright star Arcturus. Want to look up at this year's Perseid meteor shower? You're in luck. This weekend the shower should be near its peak, with less interference from a waning crescent Moon rising a few hours before the Sun. New Curiosity Images: Including a color Gale Crater vista