保护地球，探索宇宙，发现文明
2022年3月20日 A Picturesque Equinox Sunset Image Credit & Copyright: Roland Christen Explanation: What’s that at the end of the road? The Sun. Many towns have roads that run east – west, and on two days each year, the Sun rises and sets right down the middle. Today is one of those days: an equinox. Not only is today a day of equal night (“...
2021年10月5日 Sunrise at the South Pole Image Credit & Copyright: Martin Wolf (U. Wisconsin), IceCube Neutrino Obs., NSF; ht: Alice Allen Explanation: Sunrise at the South Pole is different. Usually a welcome sight, it follows months of darkness — and begins months of sunshine. At Earth’s poles, it can take weeks for the Sun to rise, in contras...
2021年9月23日 Harvest Moon Trail Image Credit & Copyright: Mike Cohea Explanation: Famed in festival, story, and song the best known full moon is the Harvest Moon. For northern hemisphere dwellers that’s a traditional name of the full moon nearest the September equinox. Seen from Saunderstown, Rhode Island, planet Earth, this Harvest Moon left a broa...
2021年9月22日 Equinox on a Spinning Earth Image Credit: Meteosat 9, NASA, earthobservatory, Robert Simmon Explanation: When does the line between night and day become vertical? Today. Today is an equinox on planet Earth, a time of year when day and night are most nearly equal. At an equinox, the Earth’s terminator — the dividing line between day and...