The Green Flash - SailNet Community
LinkBack Thread Tools
post #1 of 1 Old 02-28-2002 Thread Starter
Contributing Author
Join Date: Jan 2000
Posts: 251
Thanks: 0
Thanked 4 Times in 3 Posts
Rep Power: 16
The Green Flash

I've heard a lot about a phenomenon called the "green flash," which evidently happens at sunset. Can you explain what it is?

Dan Dickison responds:
You're not alone in wondering about this interesting sunset phenomenon, which is often dismissed as a simple product of fiction. It's true that Jules Verne popularized the green flash in his work Le Rayon Vert, and much later Herman Wouk touched on it in his Caribbean novel Don't Stop the Carnival, but it does exist. I speak from experience, having witnessed it twice.

The scientific explanation is that if the atmosphere is sufficiently clear, as the sun drops below the horizon, its rays refract. The atmosphere refracts sunlight like a giant prism, and near the horizon, this effect is intensified because the sun's rays must travel the longest possible path through the atmosphere. What I've described thus far is something you know as the sunset, so no surprises there.

Now, scientists say that the violet and blue light is scattered, and atmospheric water vapor absorbs some of the yellow and orange sunlight. What's left is red and green light, which scientists say is mostly what reaches your eyes in the final seconds of the sunset. Prisms refract the higher wavelengths less, so red light is bent less than green. What that means is that the image that reaches your eyes is both red and blue-green. Because red light is refracted less, the red is closer to the horizon than the green. When the red drops below the horizon, the green is still momentarily visible, creating a distinct green flash before it also disappears.

Sailing folklore holds that seeing a green flash is a sign of impending good weather. There's even an old English proverb that supports this view:

                                 "Glimpse you ere the green ray,
                                   Count the morrow a fine day."

Here's hoping this information at least amuses you if it doesn't fully answer your question.

Dan Dickison is offline  
Closed Thread

Quick Reply

By choosing to post the reply above you agree to the rules you agreed to when joining Sailnet.
Click Here to view those rules.

Register Now

In order to be able to post messages on the SailNet Community forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
Please note: After entering 3 characters a list of Usernames already in use will appear and the list will disappear once a valid Username is entered.

User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:


Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page

Posting Rules  
You may not post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is Off
Smilies are On
[IMG] code is Off
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On

For the best viewing experience please update your browser to Google Chrome