How Many Planets Are There in the Solar System? There are 8 planets in our solar system. The planets orbit the Sun in elliptical trajectories, and they are all different in size, composition, ...

In the remote outer reaches of planetary systems, far beyond the orbit of known planets, enormous and mysterious worlds silently loop around their stars. Some drift as far as 10,000 times the distance ...

Close stellar encounters could change the structure of our planetary system, potentially dooming Earth or other worlds to ...

Artist's impression of Planet Nine – a suspected “wide-orbit” planet – with the Sun in the distance; Neptune's orbit is shown ...

Mercury is by far the smallest planet in the solar system, with only around 5.5% of both the mass and volume of Earth.Despite that diminutiveness, Mercury manages to be the second-densest planet ...

Our Solar System is full of mysteries, but if the inner planets are a puzzle, the boundary between the Solar System and interstellar space is a secondhand puzzle with half the pieces missing.

This process, called accretion, is how everything in the solar system – planets, moons, comets and asteroids – came into being. Telescopes can see young solar systems being born.

Our solar system is looking increasingly like an oddball.” The new paper explains not only the “gaping hole” in our inner solar system, he said, but also certain characteristics of Earth and the other ...

NASA artist’s conception of a brown dwarf (main) and stock image of the planets in the solar system (inset). An object between 2 and 50 times the mass of Jupiter may have flown through our ...

Astronomers have discovered a rare solar system with six planets moving in sync with one another. Estimated to be billions of years old, the formation 100 light-years away may help unravel some ...