Does the light changes color as it travels in the space like few light years. (exclude red blue shifts)?

The Blue and Red shifts are easy to understand once you visualise the waves.

Colour is to Light exactly as Pitch is to Sound

An object at rest sends out circular ripples like when you throw a stone in water. When an object is in motion, the waves ahead of it get squashed together and the waves behind get stretched apart. The compressed waves are at a higher frequency or pitch than the stretched out waves.

No. Some people who don't like the idea of Big Bang theory and expanding universes have proposed such a thing. All such theories are lumped under the category of "tired light", the theory that light loses energy and therefore red shifts with distance.

Among physicists, it has fallen out of favor. But it's still a favorite on online forums among people who don't like Big Bang theory, despite the fact that it fails the most important test of an alternate hypothesis: It doesn't explain the data as well as the theory it is supposed to replace.

See the critiques in this Wiki article.

http://en.wikipedia.org/wiki/Tired_light

Edit: I'm afraid the "absorbed by dust" theory doesn't work. It doesn't explain the data. When we talk about "red shift" we mean that all wavelengths are shifted to longer wavelengths. Things which were in the UV might show up in the blue. Things in the red might shift to the infrared. Things in the radio spectrum shift to longer wavelengths in the radio spectrum. We see the entire spectrum of lines with their right spacing, but not at their original wavelengths.

The "dust absorption" hypothesis would predict (a) we don't see lines in the blue (we do) and (b) the lines we do see are at their original wavelengths (they aren't).

Yes, the light shifts toward the red end of the spectrum, ie its wavelength expands. This is generally attributed to a doppler shift caused by the "expansion" of space, where all objects are moving away from each other. However, this is not quite the case and there is no inertial movement of matter associated with this expansion (although there is a residual inertial movement of very distant objects away from us which is attributed to the pressure expansion left over from the big bang, and it does contribute partly to observed red shift).

This "expansion" is actually termed Inflation and the theory holds that everywhere, new space is constantly being formed, or that existing space is constantly inflating (either way, we couldn't tell the difference, or there is no difference). This is apparent in the observations that the amount of red shift observed in distance objects is proportional to that object's distance from us (more space between us and the object means more space is being formed between us and the object, meaning it's moving away faster).

However, this apparent motion does not cause a doppler shift because it is not actual inertial motion. The red shift occurs because of the time it takes the light to reach us.

Take two objects, earth and a galaxy or something, 1 billion light-years apart. The galaxy emits a light beam toward earth. Now during its 1 billion year travel, the universe expands to twice its size. This means when that light beam reaches us, it has stretched to twice its original length, hence it has halved its frequency since the speed of light is constant.

That being said, the residual momentum does contribute some to the observed redshift effect, and it is a doppler effect, but the redshift is mostly determined by how much space has expanded during its journey, rather than the relative motions of objects.

The disk of the Galaxy is filled with dust particles, and these absorb blue light more than red. As a result, starlight from distant stars in the Milky Way is more red than starlight from nearby stars. This is called "reddening". Of course individual photons don't change color, but more blue photons are absorbed than red, changing the color of the starlight.

The distribution of dust is very patchy, so the reddening is not a smooth function of distance.

Light does not change color as it travels through space. Red Shift is caused by the expansion of the universe (which makes objects move away from us), which makes light pass us a little slower, which means the light waves are passing us slower, which decreases the frequency of the light waves that pass us, which shifts the frequency toward the red end of the visible spectrum.

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properly i assume they could have been those colorations... i think of the main factor of the coloring device became into to differenciate. dazzling shade, like purple captures the attention and tells us to stop- yellow isn't fairly an identical, yet nonetheless interest grabbing. eco-friendly is mellow, so we are allowed to cruze on via. yet eco-friendly is punctiliously a distinctive shade scheme so it is elementary to tell the version from a distance. Personly, i think of orange could be surprising in determination to yellow... yet then it would be a litttttle too on the threshold of purple... i think of i could stop when I wasn't meant to... (and probable get honked at~! lol)

no

No!