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Author Topic: What causes a red rainbow?  (Read 473 times)

Offline thedoc

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What causes a red rainbow?
« on: 31/08/2016 17:23:02 »
Anthony leyland asked the Naked Scientists:
   A few days ago, just after sun down, we saw a pure red rainbow. I never knew these existed. I assume it's  down to the same reason we have red sunsets - that red light gets scattered less by the atmosphere. But I'd appreciate a more educated explanation!!
Thanks
What do you think?
« Last Edit: 31/08/2016 17:23:02 by _system »


 

Offline RD

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Re: What causes a red rainbow?
« Reply #1 on: 31/08/2016 18:05:54 »
Same reason as the orangey rainbows, see ... http://www.thenakedscientists.com/forum/index.php?topic=18551.0  [reply #9]

If the sun had actually set the red rainbow would arc very high in the sky

[ A recent one in the UK ... http://www.telegraph.co.uk/news/2016/08/25/spectacular-red-rainbow-illuminates-historic-english-town--in-ph/ ]
« Last Edit: 31/08/2016 18:23:01 by RD »
 

Offline VanVinci

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Re: What causes a red rainbow?
« Reply #2 on: 02/09/2016 05:53:16 »
Anthony leyland asked the Naked Scientists:
   A few days ago, just after sun down, we saw a pure red rainbow. I never knew these existed. I assume it's  down to the same reason we have red sunsets - that red light gets scattered less by the atmosphere. But I'd appreciate a more educated explanation!!
Thanks
What do you think?

Not so much down to the same reason but rather a result of a red sunset.

A rainbow is produced by raindrops functioning exactly like Newton's Prism.

Light enters the sunny side of a raindrop and is refracted or bent by doing so.

It then reflects off of the back inner wall of the raindrop and refracts a second time as it passes back out of the sunny side of the drop.

Newton discovered that a Prism will refract light of different wave-lengths by different angles. Resulting in 'White Light' fanning out into the ROYGBIV spectrum we all recognize.

So what happens when you only start with light of Red Wave-lengths???

:)
 

Offline Colin2B

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Re: What causes a red rainbow?
« Reply #3 on: 02/09/2016 08:19:35 »
So what happens when you only start with light of Red Wave-lengths???
If red's all you' e got, then red's all you'll get :)
 
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Re: What causes a red rainbow?
« Reply #3 on: 02/09/2016 08:19:35 »

 

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