At a distant star called Kepler-223, four gas giant planets orbit close in to their sun. It couldn't be more different from our own solar system today, where all the big planets hang out far away. But could Kepler-223 be how our solar system was long ago?
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Based on observations from the Kepler space telescope, a new study suggests yes. Perhaps Jupiter, Saturn, Uranus and Neptune were created close in to the sun. Over time, their gravities working together helped pull them away from the disc of gas and dust surrounding our sun. Once the giant planets cleared, this created room for the small planets living near the sun today: Mercury, Venus, Earth and Mars.
"Exactly how and where planets form is an outstanding question in planetary science," said lead author Sean Mills, a graduate student in astronomy and astrophysics at the University of Chicago, in a statement. "Our work essentially tests a model for planet formation for a type of planet we don't have in our solar system."
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