Many people are still upset that Pluto was demoted from being a planet. But definitions of various celestial objects are fairly fluid. So whether it is an asteroid or moon or planet is up for debate.
A giant exomoon hundreds of times the size of Earth is revealing secrets about how giant planets like Jupiter and Saturn formed. They might also help astronomers find planets where life may thrive.
Although the rings of Saturn may look like a permanent fixture of the planet, they are ever-changing. New analyses of the rings reveal how and when they were made, from what and whether they'll last.
There's a mysterious lack of small bodies beyond Neptune, but a 'snowman-shaped' object may help explain why.
The Hubble Space Telescope has spotted clouds and storms on the solar system's ice giants.
Discovery of many icy worlds helps unravel the solar system's history.
New experimental results on methane may help us to uncover whether Uranus really is the coldest planet.
The Voyager space probes sent back some amazing images of the planets in the outer Solar System, and they're still talking to Earth every day via Australia's tracking station.
Why Planet Nine should be found in the next few years ... if it exists.
How a bunch of pebbles could have created Jupiter, Saturn, Neptune and Uranus.
Space scientists have a busy decade ahead with plans to visit Jupiter, Mars, Mercury and other interplanetary bodies all on the cards.