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Inside our solar system, we have eight planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.

The Kepler space telescope has been searching for planets outside of our solar system (called exoplanets) for years, and so far has found over 2,000 of them. Scientists think that there are billions (maybe even 100 billion) planets in our Milky way galaxy alone. Imagine how many more in the universe!