Green Flash Sunset

What is a Green Flash Sunset?

Every evening at sunset, beachgoers stare out over the water in hopes of catching a glimpse of a “green flash” sunset. Some think it is just a myth. Others claim it is an effect brough on by too much rum punch. But what is the truth behind this phenomenon?

What is a green flash sunset?

A green flash sunset is an optical phenomenon that takes place when the sun is almost completely below the horizon when just a peep of the sun is still visible. Just for an instant, the upper rim of the sun will have a bright green flash. Since it takes place so quickly, just a second or two, it looks like a flash of green.

What causes a green flash sunset?

The green flash is caused by a refraction of sunlight that is intensified by a mirage. The sunlight bends as it passes through the atmosphere, similar to how a prism bends light. Different colors of light behave differently depending on their wavelengths. Green has a relatively short wavelength, so it will bend more dramatically and will be the most visible as the sun dips below the horizon.

What are the best conditions to see a green flash?

Since green flashes are caused by the refraction of light, it is important that the air be calm and the sky clear. It is also crucial to have an unobstructed view of the sunset.

Can you only see green flashes at the beach?

While green flashes are more common to see at the beach, it is possible to see them over cloud and mountain tops as well.

Are there other colors that flash during a sunset?

Yes!

While green flashes are the most common, blue and violet flashes have been known to happen. Blue and violet also have short wavelengths, but they usually scatter quickly and can’t be seen. However, on particularly clear evenings when the atmosphere is just right, people can see a blue or violet flash.

Can green flashes happen at sunrise?

Yes!

If you are an early riser, you can wake up to a green flash sunrise over the Antiguan harbour. Since green flashes are caused by the refraction of light in the atmosphere, the same phenomenon happens regardless of whether the sun is on its way down or up.