Don't peek at the answer until you've given this a good try! Then, scroll down a bit and the truth will be revealed to you.
Photo Credit: Stephen James O’Meara / Volcano Watch International
What in the world is it?
A glowing inch worm? The flagella of a deep-sea fish? A distant image of the Blue Man group under fluorescent lights? Well, believe it or not, what you see here is a rare image of the very upper limb of the Sun setting behind a distant mountain with the appearance of the “Blue Flash” -- an atmospheric phenomenon that occurs at the last moment of sunset or just before sunrise when the atmosphere is very clear and transparent (free of pollutants). The “flash” isn’t a “pop” light a camera flash. It means the phenomenon is over in a split second -- blink and you might miss it; it’s gone in a flash. While you should never look directly at the Sun, because the intense radiation could cause eye damage, the very last fragment of Sun that produces the green or blue flash occurs very low in the sky, when the light is subdued.