The Moon is believed by many to have been part of the earth and that it was tore off as a result of an initial spin that was too great to hold the planet together. One of the prevailing theories was that involving an impact of large magnitude involving the newly formed Earth and a giant object of the size of Mars hitting Earth and blowing up material that later formed the moon.

Q7. Astronomers mainly use the Hubble galaxy classification system when trying to recognize a particular galaxy as belonging to a particular type. The system was created by Edwin Hubble in the twentieth century, as the American Astronomer came up with three groups through which one could classify any galaxy in the universe. Elliptical galaxies look like ellipses, light being distributed evenly. Spiral galaxies are similar to Elliptical galaxies, but they differ through the fact that they are...
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