So the sky is blue because short wavelengths of light coming from the Sun (blue, etc.) are scattered more than long ones (yellow, red, etc.), reflecting the short wavelength light into our eyes instead of it passing through the atmosphere as part of white light. Sunsets are red for the opposite reason … but yeah, why isn’t it violet?
Violet has an even shorter wavelength than blue light. So does indigo, whatever that is. There’s a good logical case for a purple sky, right?
Want to know the answer? Why the sky isn’t violet?
The truth is that the sky is both violet and blue. But the color receptors in our eyes don’t see violet very well, so we get the (incorrect) impression that the sky is just blue. Some birds actually see well into the violet and ultraviolet, so the sky must look trippy as hell to them.
Up Goer Five
Neil Tyson once lamented that the Saturn V rocket, a vehicle once heralded as the first generation of a coming era of interplanetary rocket travel, was taken for granted by a world looking to the future. And instead of the first of its kind, it was the last.
We haven’t surpassed the Saturn V. The largest, most powerful rocket ever flown by anybody, ever, the thirty-six-story-tall Saturn V was the first and only rocket to launch people from Earth to someplace else in the universe. It enabled every Apollo mission to the Moon from 1969 through 1972, as well as the 1973 launch of Skylab 1, the first U.S. space station.
Inspired in part by the successes of the Saturn V and the momentum of the Apollo program, visionaries of the day foretold a future that never came to be: space habitats, Moon bases, and Mars colonies up and running by the 1990s. But funding for the Saturn V evaporated as the Moon missions wound down. Additional production runs were canceled, the manufacturers’ specialized machine tools were destroyed, and skilled personnel had to find work on other projects. Today U.S. engineers can’t even build a Saturn V clone.
With this epic, holy-crap-rolling-on-the-floor-laughing-but-also-crying comic, xkcd provides us with a simplified set of plans, in easy-to-understand terms, to build the Saturn “Up Goer” Five/V. Think of it as a swift kick in the pants to get our space-exploration efforts back on the right track.
Sure, what was impossible yesterday can be made possible today, through the hard work and application of science. But we must also remember that if we don’t keep stoking the fires of curiosity, what was possible yesterday can be made impossible today.
Otherwise, much like failing to point the end with lots of fire toward the ground, we will find ourselves “having a bad problem and you will not go to space today”.
The odds of a tie vote, as in perfectly down the middle, in every 2012 battleground state are astronomically small. But they aren’t zero. Let What If? take you on a journey through odds, strange ways of dying, and how tied elections relate to being hit by airborne bales of cocaine, as only Randall Munroe can.
Quattuordecillion is a very big number.
XKCD’s “What If? series asks what would happen if we all pointed laser pointers at the Moon at the same time. As you might predict, not a whole lot. But as things tend to do over in that neck of the woods, it escalates quickly, and the definition of “laser pointer” starts to get a bit dangerous.
“…let’s mount a megawatt laser on every square meter of the surface of Asia. Powering this array of 50 trillion lasers would use up Earth’s oil reserves in approximately two minutes, but for those two minutes, the Moon would look like [the photo above]”
You know it doesn’t stop there, right? Let’s just say the end result is exactly what we would deserve for being curious cats chasing laser pointers.
Check out the full inquiry at What If?.
“What I like doing is finding the places in those questions where normal people — or, people who have less spare time than I do — think, “This is stupid,” and stop. I think the really cool and compelling thing about math and physics is that it opens up entry to all these hypotheticals — or at least, it gives you the language to talk about them.”
Last year, the comic/blog XKCD had the Internet examine various colors and name them. They ended up with a sample size of 5,000,000, and designer Stephen Von Worley turned the 2,000 most common responses into a gender-exploring interactive infographic. As it seemingly turns out, men and women call the same colors different names.
Hat tip: Flowing Data
When a comic becomes a science experiment, this is what happens. And it is awesome.