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 ...

There is a reason the most recognizable planet orbiting two stars is the fictional desert world of Tatooine from Star Wars.

After studying thousands of computer simulations of the solar system, researchers at Rice University and the Planetary Science Institute think there’s a 40% chance an elusive “Planet Nine” or “Planet ...

Forbes contributors publish independent expert analyses and insights. Leslie Katz covers the intersection of culture, science and tech. A yellowish-orange glow bathes Phainoterra, a planet of dramatic ...

NORFOLK, Va. — Each planet in our solar system takes a different amount of time to complete one orbit around the sun. For example, Mercury, being closest to the sun, takes just 88 Earth days to ...

I’m a planetary scientist who was born the year of Sputnik’s launch. Over the course of my 40-year career, I’ve witnessed not one but at least five separate revolutions that fundamentally transformed ...

A possible cousin of Pluto seems to be circling the far reaches of the solar system. The dwarf planet candidate 2017 OF201 travels in a superwide orbit, with the sun relatively near one end of its ...

A rocky planet in the Milky Way galaxy may have an atmosphere, raising the possibility that life could exist on its surface, according to experts. TRAPPIST-1e, a planet belonging to a collection of ...

Unfortunately for science fiction fans, desert worlds outside our solar system are unlikely to host life, according to new research from the University of Washington. Scientists show that an ...

Even at a glance, the planets in our solar system are wildly diverse. Huge and small, airless and densely packed with ...