Driving my daugther to school this morning we were treated to the sighting of no less than 4 rainbows , including a double rainbow . Also we saw something we had never seen before, two rainbows side by side (picture McDonalds golden arches). I'd have loved to find that pot of gold. I understand the physics of a double rainbow, but I'll need more coffee for the McDonalds rainbow.

I can not begin to imagine how a McRainbow would form - more than cool.

The best double rainbow I've ever seen was over the skyline of Paris, after a line of big storms had moved through and they were against a pitch black sky. Of course i didn't have my camera with me, since I didn't want it to get wet. #-o

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That is soooooo cool, I remember seeing a beautiful double rainbow in Tucson, Arizona. In Physics Today of November (I think) there is a little note about double rainbows and that the dark region in between the two is produced by destructive interference.
The McRainbow I would love to have seen.

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Anybody ever see a complete rain circle? For that you have to be above the ground and looking downward to see the bow curve back around on itself. The best picture I ever saw of one was a pic taken from a helicopter looking down into a waterfall.

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I think I've even seen a triple rainbow, though the third was very faint. The "McRainbows" sound very strange - I don't know what would cause that.

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Me, too. I would think there would have to be two light sources to create non-concentric rainbows. Maybe hullaballo lives where they faked the moon landings.

Hmm. Could sundogs be bright enough to generate their own rainbows?

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I would not think so, but I have seen rainbowy sundogs, in other words, the disk of light that is the sundog actually goes from red to violet across the disk. I've also seen that with the sun, when it is seen through high, semi-thick clouds, where the disk is blurred and changes color, usually from top to bottom.

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At night the stars put on a show for free (Carole King)

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[quote]McRainbow, very funny, I had to stop laughing before I could write this. I once saw a lot of short rainbows in the clouds - they never touched the ground and were only fragments but they were cool.

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Just speculating here, but if there were two sources of droplets in the air, with a distinct gap between the two, couldn't rainbows form in both of them from the same light source? That could create the 'M' effect.

On a side note, you can see lots of rainbows at Niagara Falls on a sunny day. Makes it easy to photograph a double rainbow.

The position of a rainbow is determined by the position of the observer relative to the light source - if you're at the right angle, you'll see a rainbow, otherwise you won't. I don't understand how you can get "McRainbows" without a second light source.

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Two sources of droplets, one behind and slightly to the side of the other? :-?

This page seems to explain it well
http://www.jimloy.com/physics/rainbow0.htm

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I don't see an answer to the McRainbows problem. Anyone got Les Crowley's phone number? :-k

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Maybe hullaballo wasn't wearing his glasses! :wink:

I don't see it either. It seems you'd either need a mirage or some method of seriously distorting the rain drops (so they're no longer spherical).

I've read that such an effect explains things caused by ice crystals: halos, arcs, sundogs, etc. You can have muliple types (shapes) of ice crystals, each of which has a different optical effect. This is a good website about it:
http://www.sundog.clara.co.uk/atoptics/phenom.htm and you can even download a simulation program that lets you play with different types of ice crystals and get different effects. Unfortunately the site had limited info on rainbows.

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At night the stars put on a show for free (Carole King)

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Are we sure hullabaloo is desribing rainbows that are not concentric? I'm not sure I get that from the oringinal post.

We appear to be talking a Double McRainbow (hold the onions). 8)

I can only imagine the Sun being strong enough to do a Double Mac. I wonder if a distinctive cloud formation was directly behind them which allowed sun rays to split and cause the dual doubles.

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i still cant find the pot of gold at the end of the rainb :roll: ow!!!!

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That would of been cool to see.

I think the weirdest thing I ever saw was when i was a kid would be the morning of two sun's.

went out to walk to school which was west of our house. And here there was a sun rising in the west, a really stretched out and weirdly distored one... And the usuall nicely round one rising in the east.

I looked down and could see my normal shadow, and looked behind me and could see a very faint second shadow the other direction heading away from this very odd looking sun.

By the time I got to the school the mysterous second sun in the west had risen more until it had vanished.

I told my science teacher about it and remarkably he had seen it also, although he had thought it was just a reflection off the window as he was inside.

That night once my dad got home, he asked me if I had seen the mirage of the sun in the west that morning.

Trippiest thing I ever saw that mirage. Turned out it was caused by a very rare triple inversion layer, that caused a distorted image of the sun to be reflected back from the west.

It had a lot of people freaked out though as this was in 1976, and project blue book was called in to investigate it!

Would love to see that again, but evidently it's very rare for a triple inversion to happen over land, that can cause refletive mirrages.

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A sighting of double nonconcentric rainbows has been discussed recently on the Straight Dope MB; (with photos)
turns out one of the rainbows was caused by sunlight reflecting off a large body of water.

Could this perhaps be an explanation?

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