What causes the strange green flash at sunset and sunrise on Earth?
There are very special cases, when the sky is very clear and exceptionally transparent, that a green flash can be glimpsed just as the very topmost part of the sun is rising or setting.
![What causes the strange green flash at sunset and sunrise on Earth?](https://cdn.mos.cms.futurecdn.net/WV3Bh8TGjQFCK3YNNtxz3g.jpg?#)