Facts about rainbows!

Thanks to the matchbox swap the girls have being studying rainbows for the last couple of weeks and very much enjoying it.  It has brought to me facts that have amazed me as well as ones I already knew.  Here are some facts about rainbows you may or may not know:

• Rainbows can also be seen during night time! Moonlight can produce enough light to create a rainbow at night. It is called a lunar rainbow or 'moonbow'.  Moonbows are rare because moonlight is not very bright. A bright moon near to full is needed, it must be raining opposite the moon, the sky must be dark and the moon must be less than 42º high. Because of this you do not get to see a moonbow very often!  They usually appear without colour because their light is not bright enough to activate the cone colour receptors in our eyes. Nonetheless colours have been reported and might be seen when the moon is bright.
  
  
  A moonbow photographed from the edge of Haleakala crater on the island of Maui. Photograph: Wally Pacholka, AstroPics.com

• Rainbows are made up of seven colours, right?  Wrong.  They have 7 main colours but they are actually made up of the entire spectrum of colours even those we can't see.  Nobody sees colours the same, everyone’s eyes react differently depending on how much light there is, so some people may see more colours than what you see.
• It was Sir Isaac Newton who discovered that sunlight falling upon a prism could split into its component colours. It was Newton who named the colours of the rainbow: red, orange, yellow, green, blue, indigo and violet. 
• When you look at a rainbow you are actually looking at light being bounced of certain raindrops.  Interestingly enough, the person next to you is looking at the rainbow from a totally different angle and different raindrops are being reflected, which makes each person’s rainbow completely unique.
• A rainbow appears after it has been raining; the sun is always behind you and the rain in front of you when a rainbow appears, so that the centre of the rainbow's arc is directly opposite the sun. It doesn't have to rain to see a rainbow though!  Rainbows can be seen in the early morning dew, in the mist from a waterfall or in the spray of water from the ocean!
• Rainbows are the universal symbol of peace and harmony.
• Rainbows are actually circles!  When you see a rainbow from the ground, you see an arc of colours, however, when a rainbow is seen from a plane it is possible to see an entire circle as you can look down on raindrops!