why is the sky blue? On a clear sunny day, the sky above us looks bright blue. In the evening, the sunset puts on a brilliant show of reds, pinks and oranges. Why is the sky blue? What makes the sunset red? To answer these questions, we must learn about light, and the Earth's atmosphere. THE ATMOSPHERE The atmosphere is the mixture of gas molecules and other materials surrounding the earth. It is made mostly of the gases nitrogen (78%), and oxygen (21%). Argon gas and water (in the form of vapor, droplets and ice crystals) are the next most common things. There are also small amounts of other gases, plus many small solid particles, like dust, soot and ashes, pollen, and salt from the oceans. The composition of the atmosphere varies, depending on your location, the weather, and many other things. There may be more water in the air after a rainstorm, or near the ocean. Volcanoes can put large amounts of dust particles high into the atmosphere. Pollution can add different gases or dust and soot. The atmosphere is densest (thickest) at the bottom, near the Earth. It gradually thins out as you go higher and higher up. There is no sharp break between the atmosphere and space. LIGHT WAVES Light is a kind of energy that radiates, or travels, in waves. Many different kinds of energy travel in waves. For example, sound is a wave of vibrating air. Light is a wave of vibrating electric and magnetic fields. It is one small part of a larger range of vibrating electromagnetic fields. This range is called the electromagnetic spectrum. Electromagnetic waves travel through space at 299,792 km/sec (186,282 miles/sec). This is called the speed of light. The energy of the radiation depends on its wavelength and frequency. Wavelength is the distance between the tops (crests) of the waves. Frequency is the number of waves that pass by each second. The longer the wavelength of the light, the lower the frequency, and the less energy it contains. COLORS OF LIGHT Visible light is the part of the electromagnetic spectrum that our eyes can see. Light from the sun or a light bulb may look white, but it is actually a combination of many colors. We can see the different colors of the spectrum by splitting the light with a prism. The spectrum is also visible when you see a rainbow in the sky. The colors blend continuously into one another. At one end of the spectrum are the reds and oranges. These gradually shade into yellow, green, blue, indigo and violet. The colors have different wavelengths, frequencies, and energies. Violet has the shortest wavelength in the visible spectrum. That means it has the highest frequency and energy. Red has the longest wavelength, and lowest frequency and energy. LIGHT IN THE AIR Light travels through space in a straight line as long as nothing disturbs it. As light moves through the atmosphere, it continues to go straight until it bumps into a bit of dust or a gas molecule. Then what happens to the light depends on its wave length and the size of the thing it hits. Dust particles and water droplets are much larger than the wavelength of visible light. When light hits these large particles, it gets reflected, or bounced off, in different directions. The different colors of light are all reflected by the particle in the same way. The reflected light appears white because it still contains all of the same colors. Gas molecules are smaller than the wavelength of visible light. If light bumps into them, it acts differently. When light hits a gas molecule, some of it may get absorbed. After awhile, the molecule radiates (releases, or gives off) the light in a different direction. The color that is radiated is the same color that was absorbed. The different colors of light are affected differently. All of the colors can be absorbed. But the higher frequencies (blues) are absorbed more often than the lower frequencies (reds). This process is called Rayleigh scattering. (It is named after Lord John Rayleigh, an English physicist, who first described it in the 1870's.) WHY IS THE SKY BLUE? The blue color of the sky is due to Rayleigh scattering. As light moves through the atmosphere, most of the longer wavelengths pass straight through. Little of the red, orange and yellow light is affected by the air. However, much of the shorter wavelength light is absorbed by the gas molecules. The absorbed blue light is then radiated in different directions. It gets scattered all around the sky. Whichever direction you look, some of this scattered blue light reaches you. Since you see the blue light from everywhere overhead, the sky looks blue. As you look closer to the horizon, the sky appears much paler in color. To reach you, the scattered blue light must pass through more air. Some of it gets scattered away again in other directions. Less blue light reaches your eyes. The color of the sky near the horizon appears paler or white. THE BLACK SKY AND WHITE SUN On Earth, the sun appears yellow. If you were out in space, or on the moon, the sun would look white. In space, there is no atmosphere to scatter the sun's light. On Earth, some of the shorter wavelength light (the blues and violets) are removed from the direct rays of the sun by scattering. The remaining colors together appear yellow. Also, out in space, the sky looks dark and black, instead of blue. This is because there is no atmosphere. There is no scattered light to reach your eyes. WHY IS THE SUNSET RED? As the sun begins to set, the light must travel farther through the atmosphere before it gets to you. More of the light is reflected and scattered. As less reaches you directly, the sun appears less bright. The color of the sun itself appears to change, first to orange and then to red. This is because even more of the short wavelength blues and greens are now scattered. Only the longer wavelengths are left in the direct beam that reaches your eyes. The sky around the setting sun may take on many colors. The most spectacular shows occur when the air contains many small particles of dust or water. These particles reflect light in all directions. Then, as some of the light heads towards you, different amounts of the shorter wavelength colors are scattered out. You see the longer wavelengths, and the sky appears red, pink or orange.

Rsoes are geern Voielts are ornage I'm colorbilnd and Dixlesic.

why was the kid crying his dad is a alchoholic

What's grey and can't swim? A castle.

It's yellow and you'll die when it comes into your eye. A taxi.

how many blondes does it take to screw in a light bulb? --probably just one, unless cerebral palsy runs in her blood, therefore her aid would assist her.

Why was the anti-joke poster offended by all of the thumbs down? Because he didn't understand the concept of an anti-joke and instead submitted a childish, racist, incoherent lame 'joke'. This filled him with angst because he is uneducated and doesn't respond well to criticism.

What did the cow say to the other cow? Moo.

Q. What do you call a small hen that can't lay eggs properly? A. A small hen that can't lay eggs properly.

ill take a bullet for you... on call of duty... nahhh that ruins my kd

Why did the duck cross the road? Because he wanted to. Problem, AntiJoke community?

Why lets go Mets? Lets go Yankees!

Q: Why did Sally keep falling off the swing? A: She had no arms. Knock knock. Who's there? Not Sally.

Son: Mommy can I have some cookies? Mom: Sure, they're on the top shelf! Son: But I don't have any arms! Mom: No arms, no cookies!

Sally heard a scream in a dark room and went to go see who it was. Knock Knock! Who's there? Not Sally...

whats something you really wanna call a black person it starts with an "N" and ends in an "R" A. Friend i was joking about the "N" and "R"

If you search "fat black man" on Google, you will find many reesults about black people who happen to be chronicly obese.

what did the little boy say to his sibling? dat not funny!

God is real.

I got stopped for speeding the other day. The policeman said I had to pay a £50 fine. I was gutted. However, later that night I had amazing sex with my wife, which helped me to take my mind off things a bit.

Why did Julia fall of the swings? She had no arms. Knock knock? Who's there? Not Julia.

Why did the man go to Jupiter? Because he was on a classified space mission for N.A.S.A.

I was about to do an triathlon, but i took an arrow to the knee. It got infected and i promptly died two days later.

Why was chuck norris the anti christ? Christianity was being threatened....

Anti Joke

What are Antijokes? Anti Jokes (or Anti Humor) is a type of comedy in which the uses is set up to expect a typical joke setup however the joke ends with such anticlimax that it becomes funny in its own right. The lack of punchline is the punchline.

Our Updated iOS App!

We've just released huge update to the iOS app! Now, access all your favorite text and photo sites like Anti-Joke, DIYLOL! A few things didn't make the original cut (like comments) but they'll be back soon. Best of all, the app is now FREE! Get it here.

The Anti Joke Book


NEW ANTI-JOKE BOOK!  Now that we've resolved the printing issues with our publisher, check out the BRAND SPANKING NEW Anti-Joke Book!

MOAR??

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