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Reading Memo #5 - The light from a galaxy(its spectrum is...

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The light from a galaxy (its spectrum) is helpful to scientists because they can determine what elements make up for the composition of the galaxy and compare them to familiar spectra that they see in nearby stars such as the sun. If a galaxy is moving away from us, the light given off by that galaxy will undergo a redshift. On the other hand, a galaxy moving toward us will be blueshifted. The formula for a redshift is as follows: z = (wavelength (observed) – wavelength (emitted))/wavelength (emitted). For galactic speeds that are slower than the speed of light the formula is just simply: v = (speed of light) * redshift. Scientists have discovered that nearly all the galaxies they have studied are being redshifted and moving away from us. Only a few are moving toward our galaxy. Also, more distant galaxies have greater shifts that nearby ones as evidenced by the Hubble law. Walls – sheets or bubbles that interlace with one another to form a sponge-like shape.
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