This photo, taken by Allison Goz, was posted to Reddit by her boyfriend, Brent Rossen. They were curious about why the swamp was rainbow-colored. The BBC reports:

The couple were walking at First Landing State Park, Virginia, US, when they saw the unusual natural phenomenon.

Jeff Ripple, a former Florida swamp walk leader, told the BBC: "The rainbow sheens found as a thin film on top of pooled water in swamps and marshes are the result of natural oils released by decaying vegetation or the biological processes of anaerobic bacteria reducing iron in soil.

Daniel Mercadante uses colored lights and long exposures to create his Rainbow Roads series of photos. Read the rest

After careful examination of several practically-identical products and a thorough delve into reader reviews, I can finally make my long-awaited recommendation for a strap-on unicorn horn: the YanJie Shiny (~$10, Amazon).

Aside from the critical rainbow model, it comes in various colors, is adjustable, and has the all-important strap so it doesn't come off your head when under extended or vigorous use.

It is five inches long, made of polyester, and a buck or two more expensive than the competition. For an item so important, though, it's worth splurging.

"I am an 'average sized' adult and I wore this for a party," writes D.T. "it fit perfectly."

"Using for cosplay and cosplay only," reports Queen of the Succubi. "It is legit enough."

"We love it, dog hates it," cautions Daniel. "What more can I say."

If you know of a superior shiny rainbow strap-on unicorn horn, tell us about it in the comments!

YanJie Shiny Unicorn Horn [Amazon]

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Contrary to the product description, these Rainbow-Shitting Unicorn Socks [Amazon] are not "womens" socks. They're my socks.

20% polyester 75% cotton, 20% polyester, 5% spandex. Approximately fits women's shoe size 5-10. Made in Korea.

Someone on a crane captured this stunning video of a full circle rainbow. Unfortunately most of us never get a chance to see circle rainbows because the ground interrupts. Here's an explanation from Phil "Bad Astronomy" Plait in Slate:

...To see a rainbow, you face away from the Sun (180°), then look about 42° away from that point (180°–138°). The drops in an arc along that angle will then bend the light back toward you, and you get a rainbow, with the colors spread out a bit because they bend by different amounts.

Oh, wait. Did I say “arc”? Because technically, any raindrop 42° away from the anti-solar point (ooh, fancy science-speak again) will bend the light back to you. We see rainbows in the sky because in general the ground is close to you. When we look up toward the sky we see for a long way, and there are lots of raindrops along your eyeline that can add their light together to make the rainbow. When you look down, the ground gets in the way, there aren’t as many drops, and you don’t see a rainbow.

(via DIGG)

(image above via WoahDude) Read the rest

In March, brand-new Twitter account @SciSupport_BN mysteriously answered science questions, many of which had gone unanswered for years. The real fun started when Bill Nye himself filmed the replies. Read the rest

big_mac_heart_attack posted this gorgeous example of a "fallstreak hole" with a rainbow in a cloud formation over eastern Victoria, Australia. They are rare enough that some people think they are evidence of UFOs. Unfortunately, that isn't usually the case. From Weather Underground:

Fallstreak holes form in these high to mid-level (cirrocumulus or altocumulus) clouds which are comprised of tiny water droplets that are below the freezing temperature but have not yet frozen (called supercooled water droplets). Airplanes passing through the cloud help the supercooled water droplets freeze. Air expands and cools as it passes over the wings and the propellor blades, decreasing the ambient temperature just enough to allow the droplets to freeze. The ice crystals grow and start to fall, while causing the water droplets around the ice crystals to evaporate. This leaves a large hole in the cloud with brush-like streaks of ice falling below it.

By Deviantartist k-rui. Read the rest

The physics blog Skulls in the Stars has answers to your rainbow-related questions. Among the fascinating things we learn here — each color in a rainbow represents the light reflected by a separate group of raindrops; skydivers can see circular rainbows; and the famous double rainbow happens when light bounces off the inside of a raindrop not just once ... but twice. Read the rest