If the object really is Planet Nine, it would be larger than Neptune and exist 700 times further from the sun than Earth.

A planet has been predicted to orbit the sun with a period of 10,000 years, a mass 5x that of Earth on a highly elliptical ...

Our solar system may have a ninth planet after all, following the declassification of Pluto nearly two decades ago, ...

Science textbooks may be in for another revision. Our solar system shrank from nine planets to eight after the International ...

The hunt for Planet Nine—the solar system’s ghostly gravitational troll—is longstanding, and is based on the peculiar clustering of rocky bodies in the Kuiper Belt beyond the orbit of Neptune.

Caroline Delbert is a writer, avid reader, and contributing editor at Pop Mech. She's also an enthusiast of just about ...

A ninth planet the size of Neptune may be hidden in the far reaches of the solar system, but the evidence has left some experts skeptical.

Scientists may have just spotted Planet Nine — a massive object orbiting 700 AU from the Sun. Data from two space telescopes ...

The 950-foot hunk of primordial matter is classified as a "potentially hazardous asteroid," but that doesn't mean it has a ...

Astronomers claim to have discovered a new ninth planet in our Solar System. Planet Nine, also known as Planet X, is a hypothetical celestial object that would distantly orbit our Sun – but ...

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