土星与达文西灰光
影像来源与版权:Tunc Tezel (TWAN)

说明:在5月2日那天早起的人们,可见到土星及邻近的残月,低悬在东方的地平线上方。这幅在那天摄于土耳其布尔萨市的影像,呈现了这颗明亮的行星、日耀蛾眉月、与暗淡的月球夜面。这种月面灰光,则是从月球夜面反射的地照光。而早在500多年前,达文西就曾笔述:从地球海洋反射的阳光映在月亮黝黑的夜面上,形成了地照光。5月2日于破晓曙光中升起,散发著灰光的残月,在天空中还有金星这颗明亮的晨星为伴。而5月2日,也是达文西在1519年去世后的第五百周年。(译注:地照光的主要来源,其实是被地球云层反射的阳光。)
翻译:“每日一天文图”成大物理分站

Saturn and the Da Vinci Glow
Image Credit & Copyright: Tunc Tezel (TWAN)

Explanation: On February 2nd early morning risers saw Saturn near an old Moon low on the eastern horizon. On that date bright planet, sunlit crescent, and faint lunar night side were captured in this predawn skyscape from Bursa, Turkey. Of course the Moon’s ashen glow is earthshine, earthlight reflected from the Moon’s night side. A description of earthshine, in terms of sunlight reflected by Earth’s oceans illuminating the Moon’s dark surface, was written over 500 years ago by Leonardo da Vinci. On May 2nd an old Moon also rose in the predawn twilight. On that date its ashen glow shared the sky with Venus, the brilliant morning star. May 2nd also marked the 500th anniversary of Leonardo’s death in 1519.
Astronomy Picture of the Day 05/04/2019