It's time to meet 2014 MU69.
MU69 is far from your run-of-the-mill solar system object.
It's the farthest object we've ever spotted in our neighborhood.
And it's going to keep on smashing them.
And it could help prove the existence of Planet Nine.
From the Popular Science archives.
Is there a planet—or even planets—waiting to be discovered out there?
Something's got the Kuiper belt's rocks off, and there's a scramble to find it.
Another day, another hypothetical object on the outskirts of the solar system.
A gallery of photos, visualizations, and other pictures of outer space.
A sky full of super-Earths
More exciting news about cold, dead rocks
It could give us clues to how water got to Earth
This summer, the mission may get funding to travel to a mysterious rock at the edge of the solar system
How skeptical should we be, and how will we find out if this mystery planet is really out there?
Scientists are hot on the trail of our solar system's 9th planet
A total eclipse of the heart
Can you feel the love?
Popular Science goes way back
Witness history in the making
New Horizons scientist Leslie Young discusses what to expect from the flyby on Tuesday, and the 28-year wait leading up to it
And he thinks the upcoming flyby will prove it
This year's missions to the outer solar system are set to shake up the planetary family tree