意大利上空的淘气精灵
ELVES Lightning over Italy
Image Credit & Copyright: Valter Binotto
Explanation: What’s that red ring in the sky? Lightning. The most commonly seen type of lightning involves flashes of bright white light between clouds. Over the past 50 years, though, other types of upper-atmospheric lightning have been confirmed, including red sprites and blue jets. Less well known and harder to photograph is a different type of upper atmospheric lightning known as ELVES. ELVES are thought to be created when an electromagnetic pulse shoots upward from charged clouds and impacts the ionosphere, causing nitrogen molecules to glow. The red ELVES ring pictured had a radius of about 350 km and was captured in late March about 100 kilometers above Ancona, Italy. Years of experience and ultra-fast photography were used to capture this ELVES — which lasted only about 0.001 second.
Tomorrow’s picture: moon shadow, moon shadow
意大利上空的淘气精灵
影像提供与版权: Valter Binotto
说明: 天空中的红环是什么？闪电。最常见类型的闪电，是出现在云层之间的银白亮闪。不过，在过去的50年里，其他类型、称为高空大气闪电的现象已被证实，其中包括红色精灵及蓝色喷流。而较少为人所知且更难拍摄的，是另一种名为淘气精灵（ELVES）的高空大气闪电。当来自电荷分离的雷暴云之电磁脉冲，向上传递并冲击电离层时，如果导致氮分子发光就会产生淘气精灵。在这幅摄于今年3月下旬的影像里，半径约350公里的环状泛红淘气精灵，出现在意大利安科纳市上方约100公里高之处。多年的经验再加上使用超高速摄影设备，让摄影者得以捕捉到这例发光时间仅有0.001秒左右的淘气精灵。
明日的图片: moon shadow, moon shadow
