Is there a planet several times more massive than Earth hiding in plain sight — a mysterious Planet Nine? A new paper gives more evidence that Planet Nine is a real place. Astronomers have discovered a tiny world far away from Neptune, and that world's path in space could point to a gravitational tug from something big — say, a Planet Nine-sized planet.
What Is Planet Nine?
Here's Why It's Important
Did the Sun Steal Planet Nine From Another Solar System?
Written by Elizabeth Howell May 21, 2018
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