all the planets in our solar system orbit the sun. a year is the time that it takes a planet to orbit the sun - it's 365 days for Earth.Mercury and venus are near the sun, so they have shorter years because they travel a shorter distance aroynd the sun. a year on Mercury is the same as 88 days on Earth.Planets that are further from the sun have longer orbits.a year on Neptune is the same as 165 years on Earth.Each planet in our solar system is different, but Mercury,Venus,and Mars are rocky planets like Earth. If you landed on these planets,you would find rocks and you could walk around on them.