Science
Related: About this forum6 Myths Everyone Believes about Space (Thanks to Movies)
http://www.cracked.com/article_19649_6-myths-everyone-believes-about-space-thanks-to-movies.html[div class="excerpt" style="border-left: 1px solid #bfbfbf; border-top: 1px solid #bfbfbf; border-right: 1px solid #bfbfbf; border-radius: 0.3077em 0.3077em 0em 0em; box-shadow: 2px 2px 6px #bfbfbf;"]6 Myths Everyone Believes about Space (Thanks to Movies)[div class="excerpt" style="border-left: 1px solid #bfbfbf; border-bottom: 1px solid #bfbfbf; border-right: 1px solid #bfbfbf; border-radius: 0em 0em 0.3077em 0.3077em; background-color: #f4f4f4; box-shadow: 2px 2px 6px #bfbfbf;"]#4. The Sun Is YellowQuick, grab a crayon and draw the sun. If you grabbed anything other than the yellow one, you're a smartass, or else you're about to fail kindergarten.
The sun is yellow; that's one of the first things most kids learn about it, right after the whole "hot" thing but before the "horrific mass of nuclear hellfire" part. The color of the sun is one of the easiest things in the world to verify, if you don't mind your eyeballs catching fire after staring at it too long. Hell, even its classification is yellow dwarf.
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The Reality:
At the risk of crushing the memory of every painting you had to make in grade school art class, the sun is not really yellow, nor is it engulfed in wavy flames. In fact, it doesn't really look like anything much. An intergalactic cue ball, maybe.
The reason the sun appears like it does to us is Earth's atmosphere, which makes its rays appear yellow-tinted. However, the temperature of the Sun is 6,000 degrees Kelvin, and any star of that particular temperature has only one color it can be: white.
jakeXT
(10,575 posts)Odin2005
(53,521 posts)tridim
(45,358 posts)They usually make the sun's surface look like a yellow-orange bubbling hellscape.
I know it's white because I know about spectrums and how color works in raytracing applications. Sunlight is always considered nearly pure white light.
A related myth, sunspots aren't black. They're just less bright than the rest of the sun.
Warpy
(111,232 posts)I admit every time I see a photograph of the Martian surface, I look closely for the prairie dogs popping up. It's not that different except for the scrub trees we do find out here.
The yellow sun myth is aided by all those photographs of the solar surface through heavy filters, showing a red surface with yellow stuff poking through it.
My own favorites are that extraterrestrial life consists not only of bipedal apelike creatures, but that we can communicate with them with relative ease. We can't communicate with other sentient species here, where we share a planetary point of reference. How the hell could we possibly communicate with a silicon based methane breathing cephalopod from Zarkon?
And this is why I got disgusted with sci fi in my 20s.
UnrepentantLiberal
(11,700 posts)tridim
(45,358 posts)and do fighter-jet style banking and turning maneuvers.
Lots of stuff in Star Wars was very wrong, but I'm still glad they did it the way they did.
hunter
(38,309 posts)Nope. Our eyes see it as white. Or yellow. Or whatever. Human color perception is notoriously complex. It's also an evolutionary kludge of the worst sort. When color vision became useful again to our furry little ancestors, once we'd crawled out of our dark holes into daylight, we'd foolishly discarded a nearly optimal reptilian color receptor. This lost receptor was recreated in a half-ass way by splitting the remaining red-green receptor we'd kept. It was a less than optimal solution. Nervous system software patches made the shortcoming less noticeable, but my parrots still see colors a lot more clearly than I do, and they look upon our color television with contempt.
My bird's optimal color receptors:
The inglorious great ape color receptor kludge:
An "Intelligent Designer" did this??? Wait. What? Was he drunk? If I'm God's favorite, shouldn't I be able to see colors in all God' Glory like an ordinary bird?
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We don't see green stars in the sky because we see them as "white."
You heat something up, what happens? It glows red-orange-yellow-white-blue... Hey what happened to the "green hot?"
That's our white.
http://en.wikipedia.org/wiki/Color_temperature
And the reason plants can afford to reflect green light is that at high noon on a clear day they are exposed to far too much energy to process efficiently. Evolution has determined that the easiest, most efficient thing is to dump this extra energy.
I fear there's probably a lesson there for the solar and wind energy people... Nameplate ratings are much less valuable than they appear. If it was worth storing peak solar energy you'd expect after a few billion years of evolution the earth would be covered with black leaved plants that did so.
cbrer
(1,831 posts)The bird visual color range is cool.
Doesn't your statement about solar/wind make some gross assumptions.
Were plants evolving to maximize heat/energy storage? Or making optimum use of materials at hand for growth and reproductive purposes? Plus energy storage may not have been the developmental goal? edit to say *mass* energy storage.
If black maximizes heat absorption, that may have damaged plants and therefore been evolutionarily discarded?
Man I'm researching solar power right now! Tell me some GOOD news!
hunter
(38,309 posts)Usually it's something else, like real estate, nutrients, temperatures, or water.
I'm speculating that most of our economic production is fixed in place, like plants, and thus the primary limitations of production will be unrelated to the gross efficiencies of solar energy inputs or storage.
Cheap inefficient solar panels and batteries that require no scarce materials will be preferred over systems that require scarce materials or complex management.
Speculation is a good thing. It seems solar panel management can be simple. Or complex. I'm leaning towards open field mounted system. Puts it where I can get to it. And tinker with tracking and maintenance issues. Thank goodness for new battery technology and climbing panel efficiency.
Last post this thread. Sorry!
txlibdem
(6,183 posts)Clearly it has 11, possibly more.
http://blogs.discovermagazine.com/cosmicvariance/2005/12/07/how-many-dimensions-are-there/
hunter
(38,309 posts)I think our perception lives in a three dimensional place. "Time" is an intrinsic property of those three dimensions. Time travel is not possible because time does not exist. Everything is writ upon the light; we're all photons and photons know not time.