Astronomy Picture of the Day——月球天文台在紫外波段拍摄的地球

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

UltravioletEarth from an Observatory on the Moon

Image Credit: G. Carruthers (NRL) et al., Far UV Camera, Apollo 16, NASA

Explanation:Which planet is this? Earth. The featured false color picture shows how theEarth shines in ultraviolet (UV) light. The image is historic because it wastaken from the surface of the Moon by humanity's first lunar observatory.(Another is operating now.) Although very little UV light is transmittedthrough the Earth's atmosphere, what sunlight does make it through might causea sunburn. The part of the Earth facing the Sun reflects much UV light, butperhaps more interesting is the side facing away from the Sun. Here bands of UVemission are the result of auroras and are caused by charged particles expelledby the Sun. Other planets showing auroras in the UV include Mars, Saturn,Jupiter, and Uranus.

月球天文台在紫外波段拍摄的地球

解释：这是哪颗行星？地球。这幅特征伪彩色照片显示，地球如何在紫外（UV）波段发光。这幅影像是历史性的，因为它是人类的第一个月球天文台从月球表面拍摄的。（另一个目前正在运行中。）虽然只有非常少量的紫外光通过地球的大气层，否则阳光确实可能造成灼伤。地球面对太阳的部分反射很多紫外光，但也许更有趣的是背对太阳的一面。这里，紫外辐射带是极光的结果，是太阳抛射的带电粒子造成的。其它行星，包括火星、土星、木星和天王星在紫外波段也有极光。