Astronomy Picture of the Day——彩虹双子座流星

Discoverthe cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

A Rainbow Geminid Meteor

Image Credit & Copyright: Dean Rowe

Explanation:Meteors can be colorful. While the human eye usually cannot discern manycolors, cameras often can. Pictured is a Geminid captured by camera during lastweek's meteor shower that was not only impressively bright, but colorful. Theradiant grit cast off by asteroid 3200 Phaethon blazed a path across Earth'satmosphere longer than 60 times the angular diameter of the Moon. Colors inmeteors usually originate from ionized elements released as the meteordisintegrates, with blue-green typically originating from magnesium, calciumradiating violet, and nickel glowing green. Red, however, typically originatesfrom energized nitrogen and oxygen in the Earth's atmosphere. This brightmeteoric fireball was gone in a flash -- less than a second -- but it left awind-blown ionization trail that remained visible for several minutes, thestart of which can be seen here.

彩虹双子座流星

解释：流星实际上是多彩的。人类的眼睛通常不能难以分辨出它的颜色，但是相机却能够做到。此图是在上周的双子座流星雨期间捕捉到的，不仅极其明亮，而且多彩。法厄同小行星（3200号）抛出的沙粒通过地球大气层留下的路径比月球角直径的60倍还要长。流星的颜色通常起源于流星解体时释放出来的电离元素，蓝绿色起源于镁，钙元素造成紫色，而镍元素则产生绿色的辉光。然而，红色通常来源于地球大气层中的氮和氧。这个明亮的流星火球一闪而过，少于一秒钟，但它留下的电离余迹却能够停留数分钟。