Vocabulary N°11

1. Galaxy: A large group  of stars held together by gravity.



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  There are three shapes of galaxies: The spiral,elliptical and the irregular galaxy.

2. Milky Way: Our home galaxy.



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  The Milky Way galaxy is where the solar system is.

3. Spectrum: A band of colors made when white light is broken up.

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  An example of the spectrum is the rainbow colors.



4. Expansion Redshift: The shift of a spectrum of a galaxy toward longer ( redder) wavelengths due to the expansion of space.



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  The Expansion Redshift is called like that because have redder wavelenght.

5. Big Bang: The beginning of the universe, when the density of the universe was very high.

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  The Big Bang happen when the Universe has expanded.

6. Background Radiation: Electromagnetic radiation left over from the big bang.



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  I have a telescope with background radiation.

7. Quasar: An extremely bright, extremely distant,high-energy source.

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  This is the collision between a quasar and a galaxy.