"How planets are born is an unsolved area of research," astrophysicist Daniel Price of Australia's Monash University told ...

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

This is probably the most convincing evidence for Planet Nine so far. It is believed that this planet is five to ten times ...

Astronomers have long speculated about an unseen planet lurking in the solar system's outer edge. This hypothetical world, dubbed Planet Nine, could explain the unusual clustering ...

The solar system is our cosmic neighborhood, made up of the sun and everything ... the eight major planets to dwarf planets, comets, asteroids, and icy objects — revolves around it.

Exquisite snapshots released on April 28 provide a rare glimpse into the earliest stages of planet formation in more than a ...

Lance Hayashida/Caltech The candidate for Planet Nine displayed a tiny amount of movement, which could mean it advanced further in its orbit around the sun. Some of the strongest evidence that ...

With the exception of Pluto, planets in our solar system are classified as either terrestrial (Earth-like) or Jovian (Jupiter-like) planets. Terrestrial planets include Mercury, Venus, Earth, and ...

The closest one to the sun is Mercury, then it’s Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. The eight planets travel around the Sun at different speeds. These lines show us the ...