There are nine planets in the solar system and all of them have something unique. We have discovered many things from exploring them. From hot Venus to freezing cold Pluto, we have tons of information of the planets and how we have explored them.
From the nearest planet from the Sun, Mercury, to the farthest planet from the Sun, Pluto, and the largest planet, Jupiter, to the smallest planet, Pluto, there is not one planet that does not have something interesting about it. Mercury has the largest temperature range. Venus is the hottest planet. Earth has life on it. Mars has a rocky red surface. Jupiter is the largest planet. Saturn has rings. Uranus has a horizontal axis not a vertical axis. Pluto is extremely cold. Can we live on Mars? Is Pluto a planet? You can find answers in our exploring planets pages.
How do we know there are nine planets in the solar system? How do we know which planets are bigger? By exploring and observing the planets, of course. Exploring and observing the planets has been going on for a long time and is still continuing. At first we used telescopes to observe planets, but now we can use spacecraft to look at planets up close. We have learned a great deal about planets by exploring and observing them. What spacecraft went to Mars? What spacecraft went to Venus? You can find the answers in our great exploring the planets web pages.