Billions of Earth-Like Planets Exist, Scientists Say
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About 4.4 billion planets are similar to Earth in size and temperature, suggesting they may be able to host life, according to a survey of the galaxy using telescopes operating in space and on the ground.
The number is an estimate based on information taken from 42,000 stars similar to the Earth’s sun and their surrounding planets by the National Aeronautics and Space Administration’s Kepler Space Telescope, as well as telescopes in Hawaii. Ideal planet climate -- not too hot or too cold -- was determined by how far they were away from their stars, according to the report in the Proceedings of the National Academy of Sciences.