why is the sky blue? why cant it be red or something?

Answer 1

The sky is red sometimes, sunrise and sunset.

Anyway...

The sky is blue partly because air scatters short-wavelength light in preference to longer wavelengths. Combined, these effects scatter (bend away in all directions) some short, blue light waves while allowing almost all longer, red light waves to pass straight through. When we look toward a part of the sky not near the sun, the blue color we see is blue light waves scattered down toward us from the white sunlight passing through the air overhead. Near sunrise and sunset, most of the light we see comes in nearly tangent to the Earth's surface, so that the light's path through the atmosphere is so long that much of the blue and even yellow light is scattered out, leaving the sun rays and the clouds it illuminates red.

Answer 2

The gaseous elements in the air acts like a prisim for the sunlight and scatteres all the colors. The color of the sky also depends on at the angle the sun is hitting the atmosphere, like when it hits the edge of it, the sky will glow reddish-orange indicating that it is dawn and that the working day is either starting or ending.

Answer 3

It is often red. The sky is viewed as the color of light that the atmosphere reflects down towards us. At the end of the day the light travels farther and is reflected red.
B

Answer 4

Blue light is at the far end of the spectrum. I'm not certain if it's the first light filtered out or the last (by earth's atmosphere), but it's the color that bounces back to your eyes as the other colors continue out into space.

Answer 5

Rayleigh scattering. Just like the other 1000 times this was asked this morning.

Answer 6

Cherenkov radiation in the upper atmosphere.

Light travelling at faster then the "speed of light travel" for that particular substance.

Answer 7

Refraction. If you change what is in the atmosphere then you will get a different colours.