Circular rainbow? Do you live at extreme latitude?

[Guv]

All the rainbows I have ever seen were about 180 degree arcs (about half a circle). My home is at about latitude 40 degrees north, and I have seldom traveled further north than about 55 degrees, and never further south than about 40 degrees.

Many years ago I speculated about rainbows, which always seem to be cut off at the horizon.

I often wondered if rainbows might form a complete (or nearly complete) circle at more extreme latitudes. Say 80 or more degrees north/south.

Yesterday on a golf course, there was a sprinkler watering the fairway. As I approached it, I saw a rainbow about 10 feet in diameter (say 3 meters) which was about a 270 degree arc (about 3/4 of a circle). This made me think about the rainbow question again.

Does anybody know if a natural rainbow can be a complete circle? Do any of you live at an extreme latitude? If so, have you seen rainbows which are much more than half a circle?

[crptcblade]

Well, I don't know, but if it was a complete circle, where the hell would the pot of gold be?

[chrisjk]

the Leprechauns steal it before anyone gets a chance to find it, the bastards

[Guv]

After much travel, I once got to the end of a rainbow and discovered a leprechaun leaning against a tree drinking Irish whiskey from a jug.

I asked if it was his job to give me the pot of gold.

He said his name was Murphy (he once wrote some laws), and it was his job to tell me that the pot of gold was at the other end.

[Beacon]

Once me and my mates were driving down south Margret River going surfing and there was this rainbow we followed the road and as we got toward the rainbow this bright yellow glow over a patch say 20 metres by 20m appeared we kept driving and in the rear mirror we could see the rainbo. It was like we drove through it or something.
Even though that cant happen can it??

360 degree rainbows i doubt could happen becuase a rainbow is just light passing though water or something isnt it and the water is always falling down and so is the light!

Perhaps if you had water falling down and a light source from the bottom and the top aligning perfectly it may i.e a reflection off of water.

[MartinLiss]

I don't know a lot about the subject but it seems to me that since the rays of the sun are essentially parallel when they strike the Earth, that it makes little difference where you live. Anyhow I found a reference via the Google search engine that says

Rare 360 degree rainbow over the wild Na Pali Coast, Kauai Island

[Jim Brown]

Martin, Did Google say where the heck that place is?

Hey Beacon, driving thru' a rainbow? You've been at the Fosters again. I dunno about the 360 degree question, but surely you can't have seen the rainbow again behind you because the sun has to be be behind you and you have to be between the sun and the water and the light refracts twice back out of the drops back to you. Unless you've got two suns round the back there? Were you standing up

[MartinLiss]

Kauai is one of the Hawaiian islands. After doing a little more research it seems that 360 rainbows are common enough to have a name - the're called "glories". They are perhaps most often seen around mountain tops and I saw a number of URLs that talked about people seeing them from planes.

[Beacon]

Well looks like i'm wrong then.



meh oh well!

Jim:

Well then you explain it then??
Where da hell did this gold light come from and where did the rainbow go?
Also it was after a while that the rainbow re-appeared in the rear view mirror like i mean a few km's!
Perhaps it wasnt the same one!
I dont know but it was pretty weird light and it's always nice to dream!

[Jim Brown]

Hang about, everyone.

Guv's first question was about extreme latitude's but Martin's Google quote was about Hawaii, which is just inside the Northern tropics according to my map.

So Guv maybe it's not extreme latitudes but... but ... ***'s the opposite of extreme.... un-extreme ie tropical latitudes.

Saludos

[Guv]

Due to MartinLiss, I did some Web searching and have been unable to find a good explanation of what Glories are. They seem to be 360 degree rainbows, but I get the impression that they are somehow different from the ordinary rainbows I have seen.

Perhaps they are caused by waterfalls instead of rain. Perhaps they are rainbows viewed from a mountain top.

As I understand a normal rainbow, the viewer is between the sun and the rain. Sunlight coming from behind the viewer enters spherical raindrops and is reflected from the far interior side of the raindrop back toward the viewer.

At my latitude (about 40 degrees north), the daytime sun is from the south. The viewer of a rainbow is always looking northeast, north, or northwest and the rainbow is cut off by the northern horizon.

It seemed to me that if rain were to fall in the artic circle, a rainbow caused by rays almost tangent to the earth's surface might be relatively high compared to the northern horizon. Under such circumstances, the rainbow might be circular or almost circular.

If standing on a mountain top less than an hour after sunrise or within an hour of sunset, the sun could be below the viewer, causing a rainbow centered on a spot higher than the mountaintop. This might result in a circular rainbow.

The above are speculations by me. I have yet to see any authoritative source describe or explain a circlular rainbow. The refernces to glories imply that the phenomena exists.

[MartinLiss]

Here are a few other links that I found when I did a rainbow physics search in google (there are more). None of these mention 360 degree rainbows but they are certainly interesting articles and they have bibliographys with other rainbow references.

http://www.phy.ntnu.edu.tw/java/Rainbow/rainbow.html

http://www.unidata.ucar.edu/staff/blynds/rnbw.html

http://www.elgin.free-online.co.uk/rainbow.htm

[opus]

Hi,I don't have any physical explanation, but I've often seen "rainbows" out of an airplane.
That is looking into a cloud with the sun behind me. The "rainbows" formed a total circle but they were definitley smaller in circle then the ones we can see on the surface of mother earth.

[Jim Brown]

Said Guv-

"At my latitude (about 40 degrees north), the daytime sun is from the south......."

So you guys have a night time sun up there too then? Must confuse the sh*t out of the cockerel who's on wake-up duty :-)

[Jim Brown]

Just for the heck of it, I thought this old thread needed resuss.

[mendhak]

Rainbows are skittles.