Redshift and Blueshift

Redshift and Blueshift
The redshift and blueshift light waves are very similar to the Doppler effect. When an object in space moves towards Earth the light waves compress into higher frequencies and shorter wavelengths; this is a blueshifted object. For redshift, the object in space moves away from the Earth; the light waves are stretched having longer wavelengths resulting in lower frequencies. 
In the electromagnetic spectrum, the blue light has the highest frequency and the red light has lower frequency. 
Most objects in the universe are redshifted because the universe is expanding. There are very few blueshifted stars, planets or galaxies in our universe. Andromeda which is the closest galaxy to us is blueshifted; it will eventually collide with the Milky Way. 
Redshift can be measured by examining its absorption or emission lines in the spectrum. The lines are very unique for each atomic element and the lines always have the same amount of spacing between them. As objects move away or towards us, the absorption or emission lines will have different wavelengths than as if the object was not moving. 
The change in wavelength of lines are used to calculate the redshift. 
Redshift = (observed wavelength – Rest wavelength)/Rest wavelength 
Cosmological Redshift 
The cosmological redshift is caused by the expansion of space. The universe is expanding and most galaxies are moving away from each other resulting in them moving faster away from us than when they were closer to us. These galaxies are redshifted. The UV and visible light is shifting to the infrared spectrum which will allow us to gain information on the UV and visible light spectrum of young galaxies. 
The faster the universe expands the farther a galaxy, a planet, or a star will get away from us and the more it will become redshifted resulting in less blueshifted galaxies or objects. 

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