保护地球，探索宇宙，发现文明
2022年7月26日 Comet NEOWISE Rising over the Adriatic Sea Video Credit & Copyright: Paolo Girotti Explanation: This sight was worth getting out of bed early. Two years ago this month, Comet C/2020 F3 (NEOWISE) rose before dawn to the delight of northern sky enthusiasts awake that early. Up before sunrise on July 8th, the featured photographer was able to ca...
2022年7月12日 Noctilucent Clouds over Paris Credit & Copyright: Bertrand Kulik Explanation: It’s northern noctilucent cloud season. Composed of small ice crystals forming only during specific conditions in the upper atmosphere, noctilucent clouds may become visible at sunset during late summer when illuminated by sunlight from below. Noctilucent clou...
2021年7月24日 The Edge of Space Image Credit & Copyright: Ralf Rohner Explanation: Where does space begin? For purposes of spaceflight some would say at the Karman line, currently defined as an altitude of 100 kilometers (60 miles). Others might place a line 80 kilometers (50 miles) above Earth’s mean sea level. But there is no sharp physical boundar...
2021年06月19日 Northern Summer Twilight Image Credit & Copyright: Justin Anderson Explanation: Nights grow shorter and days grow longer as the summer solstice approaches in the north. Usually seen at high latitudes in summer months, noctilucent or night shining clouds begin to make their appearance. Drifting near the edge of space about 80 kilometers above...