The existence of "Planet Nine," a hypothetical planet in the outer solar system, is supported by indirect evidence such as the unusual clustering of orbits of extreme trans-Neptunian objects (ETNOs) ...

It's a question that has baffled scientists around the world for years. Is there really a ninth planet hiding in our solar system? And if so, how do we find it? Now, researchers from Rice University ...

Planet Nine is a theoretical planet in the outer solar system that has proved to be extremely hard to find. | Credit: Shutterstock Some experts believe that we could be just a few years away from ...

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 ...