← Another date

Birthday · September 9, 1997

A Green Flash from the Sun

September 9, 1997

You were born on a tiny world orbiting an ordinary star in an unremarkable galaxy — and yet, the fact that you exist at all is the most...

A Green Flash from the Sun

A little universe, just for you

Your date.
Ready to give.

Free PNG · 1080 × 1350 · No account needed

Image rights and credit requirements apply when sharing or reusing imagery.

Change the year

APOD published September 9, 1997. Credit: J. C. Casado. A publication-date match, not a photo taken on your date. Independent of NASA.

Behind the image

A Green Flash from the Sun

Original APOD · September 9, 1997

Many think it is just a myth. Others think it is true but its cause isn't known. Adventurers pride themselves on having seen it. It's a green flash from the Sun. The truth is the green flash does exist and its cause is well understood. Just as the setting Sun disappears completely from view, a last glimmer appears startlingly green. The effect is typically visible only from locations with a low, distant horizon, and lasts just a few seconds. A green flash is also visible for a rising Sun, but takes better timing to spot. A slight variant of this was caught in the above photograph, where much of the Sun was still visible, but the very top appeared momentarily green. The Sun itself does not turn partly green, the effect is caused by layers of the Earth's atmosphere acting like a prism.

Image credit: J. C. Casado

Explore September 9 in other years