I took this photo on tuesday. What I'm wondering is why is the bit of sky between the two rainbows darker than the rest of the sky? I've never noticed this phenomenon before. Can anybody explain it? Also is Geoffrey from Rainbow still working in a warehouse?

That's very cool

I can only think its some type of optical illusion.

He got the sack for making a Bungle..

That reminds me of the circumciser who made a slip and got the sack.

But surely the rainbow itself is an optical illusion. :confused:

A rainbow does not actually exist at a particular location in the sky. It is, instead, an optical phenomenon whose apparent position depends on the observer's location and the position of the sun. All raindrops refract and reflect the sunlight in the same way, but only the light from some raindrops reaches the observer's eye. This light is what constitutes the rainbow for that observer. The position of a rainbow in the sky is always in the opposite direction of the Sun with respect to the observer, and the interior is always slightly brighter than the exterior.

Occasionally, a second, dimmer, and thicker secondary rainbow is seen outside the primary bow. Secondary rainbows are caused by a double reflection of sunlight inside the raindrops, and appear at an angle of 50°–53°. As a result of the second reflection, the colours of a secondary rainbow are inverted compared to the primary bow, with blue on the outside and red on the inside. The dark area of unlit sky lying between the primary and secondary bows is called Alexander's band, after Alexander of Aphrodisias who first described it.

One time I saw one that was a perfect circle in the sky. Never seen that before or since.

Alexander's band or Alexander's dark band is an optical phenomenon associated with rainbows which was named after Alexander of Aphrodisias who first described it. It occurs due to the deviation angles of the primary and secondary rainbows. Both bows exist due to an optical effect called the angle of minimum deviation. Light which is deviated at smaller angles than this can never reach the observer.
The minimum deviation angle for the primary bow is about 140°. Light can be deviated up to 180°, causing it to be reflected right back to the observer. Light which is deviated at intermediate angles brightens the inside of the rainbow.
The minimum deviation angle for the secondary bow is about 230°. The fact that this angle is greater than 180° makes the secondary bow an inside-out version of the primary. Its colors are reversed, and light which is deviated at greater angles brightens the sky outside the bow.
Between the two bows lies an area of unlit sky referred to as Alexander's band. Light which is reflected by raindrops in this region of the sky cannot reach the observer, though it may contribute to a rainbow seen by another observer elsewhere.

hey bradx get some of this spice stuff. it is well good.

i reckon its a rainbow, but in 3d. so like the ends are rainbow coloured and the middle um slats are like purple.

:applaud:

well that was a question thoroughly answered

yup - all out of my own noggin as well. Just call me 'prof.' :D







^_^







:blink:

I have made a note to :-)

if this alexander was from aplace called aphrodisias, is there, er, something else we should know about him ?

Sounds like a lad who knew how to have a good time. Bit of a 'Rainbow Rascal' as we call them 'round here/

Well, I'll be sure and point out Alexander's Band to others whenever I witness it, but I still haven't got a fruggin' clue what the hell it is.

Could you offer a 'dumbed-down' explanation please? :blink:

It's merely the dark bit between a double rainbow:)

lasts for ages too. it bends time or something ? um what i mean is that you think- "is it still yesterday ?" and you cant remember if you did something yesterday, or today, or if there actually is a today.

o kay then that made sense :D

far out. I might get mrsx to order some for me. I had 3 pints of weak beer tonight and then a veggie curry. Not bad.

i am drinking malibu.

i have started smoking. i seem to smoke quite heavily. roll ups.

i am very happy because every day doing the chores is a bit of a grind and i needed some way to get out of my head. its kind of a hobby. im interested in getting out my head on a kind of biological way as well as for entertainment purposes.

that's called 'self-medicating' I think.

hooray : D

see my pills already do alot. but they dont make me think "weeeeee im having fun !" whereas when i get out my head, i dont need to do anything else. it kind of makes things fun.

also the technical side of it is interesting as well.

Thanks for the information Bradx. :)

Don't overdo the Spice. :rolleyes:

Sometimes from my balcony I can see a complete circle rainbow. I am quite high up and this must effect how it's seen. The rainbow seems suspended in the middle distance. It goes right in between some buildings and then round the other side. Its quite strange and a bit difficult to describe :blink:

The mood of my old boss was always greatly improved by the appearance of rainbows across the street. Reading from left to right, they emerged from the church steeple, rising steadily; then the curve & dip, into The Globe Public House.

:lol: quality gag alert!!

I've sussed it. It is an optical illusion. The nature of the light refraction means that the sky to the upperside of the rainbow is lit up slightly. The sky to the underside is not lit at all.

Where there are two rainbows, the smaller rainbow is the reverse of the larger. So, the sky on the underside of the rainbow is lit up. This gives the effect of the sky between the rainbows being dark, but in fact it is only as dark as the sky outside the rainbows, but further away from the rainbows than the lit up bits of sky.

So the sky between the rainbows seems darker, but isn't.

Am I right? Am I just thick? :wacko: Isn't that what was said anyway and I just didn't realise it?

sounds spot on skipper. Not that I really know of course. I merely cut n pasted that stuff off wiki I'm afraid.
Interesting though. I like natural phenomena. In fact - here's some things I'd LOVE to see first hand;

tornado
water spout
northern lights
comet/meteorites

I would esp like to go to a really dark place - away from any town/street lights etc...and look at the night sky.

A friend told me he'd seen BALL LIGHTNING inside his old school!!!!!!!! :o
That's not possible is it? :confused:

Could be,
check this wiki page,St Elmo's fire.
The electrical charge is from the ground, I think so it could happen inside.

I was reading about Rainbows and came across that phenomenon known as Alexander's Dark Band. Imagine how pissed off I was to discover somebody had already nabbed this name for a group.

I really love 'Stargazer' by the way, it's very very funny (Ronnie James Dio is a one-man Spinal Tap AND they paid for the Berlin Philharmonic to play on it) and it rocks too.

I've seen one like that, from a plane.
Never from the ground...

sorry for being an arse but I hoped this was a discussion on
Ritchie Blackmore's Rainbow, but I guess I thought I was in the
Mojo Forum, sorry... still, Long Live Rock n Roll eh?

well, any excuse..
http://www.youtube.com/watch?v=mKVLEiE2Qs4&feature=related

Don't you ever apologise for being into Rainbow :angry: Went to see Ronnie himself singing some of the Rainbow classics a few months back.