For years, the existence of a missing Planet 9 has been one of the predominate theories attempting to explain some of the eccentric orbits found in the outer Solar System. But so far, no such planet ...

Scientists think there may be a ninth planet hiding in the distant reaches of the solar system — and a new telescope could finally prove its existence. | Credit: Nicholas Forder for Live Science Deep ...

What if Pluto wasn’t the end? What if our Solar System hides dozens - maybe hundreds - of strange frozen worlds beyond Neptune? In this video, we take you on a journey through the mysterious outer ...

Mike Brown is convinced that beyond Neptune, at the far reaches of our solar system, there's an unseen giant planet. "This is the 5th largest planet in our solar system, lurking out there, waiting to ...

According to a recent study using computer simulations, Planet 9 is out there — and it’s smaller and more like Earth than you probably expect. The Kuiper Belt is populated by dwarf planets like Quaoar ...

Could data pointing toward a mysterious planet at the edge of the solar system actually suggest it's time to revisit our theory of gravity? When you purchase through links on our site, we may earn an ...

Some experts believe that the solar system's hypothetical ninth planet could be just a few years away from being discovered. If this is the case, how long would it take for humans to send probes to ...

Astronomers have long been puzzled by the orbital mechanics of objects that act in strange and largely unexplained ways in the outer reaches of the solar system, beyond the orbit of Neptune.

Caltech researchers have found evidence of a giant planet tracing a bizarre, highly elongated orbit in the distant solar system. The object, which the researchers have nicknamed Planet Nine, has a ...

A Feb. 14 article about the planet/planetoid Sedna said that all planets orbit the sun in a circle and all planets are on a similar plane. Planetary orbits are nearly circular but slightly elliptical.