In the above artist's illustration, the scale of planets, their host stars, and their orbits have all been dramatically magnified to provide viewers with a sense of something that can get lost in the beautiful images of stars and cosmic dust clouds NASA releases every few days: There are billions of terrestrial planets in our galaxy, the Milky Way. By one recent estimate published in Nature, as many as 10 billion. The average star has more than one planet, and there are thought to be a minimum of 1,500 planets within 50 light years of Earth.
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