Mars scientists found water on. Mars
Errors in the calculations of Neptune's mass led scientists to believe that there was another planet affecting Uranus' orbit. Scientist proceeded to dub this planet Planet X.
No. It was categorised as a dwarf planet in 2006, but not all astronomers agree with that decision.
It orbits Neptune in the opposite direction of Neptune's rotation.
The dwarf planet Pluto is believed by astronomers might be the core of a much larger planet
nol
Mars. Because they have found worms on Mars. which means there is water because otherwise worms would not survive.
Earth
Mars
Astronomers have decided that Pluto does not meet the definition of a planet.
It is no longer classified as a planet as astronomers now believe its a asteroid that got pulled into an orbit with our sun. Some also believe it to be a misplaced moon of Neptune.
Most planets in the Solar System have been found or speculated to have water. But at the moment only Earth is known to have water in the liquid state. Both polar caps on the planet Mars are known to have frozen water. It is also speculated that under the crust of some moons in the outer solar system, liquid H2O oceans may exist. Outside the solar system no one knows, but just recently astronomers have discover the exo-planet Gliese581g, which seems to be the right temperature that might support the existence of liquid water on its surface.
Astronomers think Pluto is a dwarf planet. And they're right.
Neptune
Errors in the calculations of Neptune's mass led scientists to believe that there was another planet affecting Uranus' orbit. Scientist proceeded to dub this planet Planet X.
No. It was categorised as a dwarf planet in 2006, but not all astronomers agree with that decision.
pluto
The dwarf planet Pluto is believed by astronomers might be the core of a much larger planet