Nasa reveals stunning image of upside down rainbow – here’s how it was formed

NASA has shared a stunning image of an inverted rainbow that looks like a colorful smile in the sky.

The scientific name for this phenomenon is a ‘circumzenithal arc’.

NASA/Marcella Giulia PaceNasa shared this stunning image of a ‘rainbow smile’[/caption]

The picture Nasa shared was taken in Ragusa, Sicily in February.

Nasa said: “This example of an ice halo known as a circumzenithal arc was captured above a palm tree top from Ragusa, Sicily on February 24.

“The vividly colorful arcs are often called smiling rainbows because of their upside down curvature and colors.

“For circumzenithal arcs the zenith is at the center and red is on the outside, compared to rainbows whose arcs bend toward the horizon after a downpour.

“True rainbows are formed by water droplets refracting the sunlight to produce a spectrum of colors, though.”

It may be possible to see one of these ‘rainbow smiles’ for yourself if you find the right conditions.

Nasa says you need to look straight up when the Sun is low in the sky.

You’ll also need moisture in the sky for the rainbow to appear.

Nasa added: “Circumzenithal arcs are the product of refraction and reflection in flat hexagonal ice crystals, like the ice crystals that create sundogs, formed in high thin clouds.”

The US space agency liked the picture so much it made it the Nasa Image of the Day for March 11.

Earth is said to be the only planet in the Solar System with rainbows.

That’s because rainbows require precipitation and sunlight.