Who is your next door neighbor? Do you and your neighbor have a lot in common? Our planet has a neighbor. Earth's neighbor is the planet Mars. These neighbors have a lot in common. Their landforms are very similar. Both Mars and Earth have canyons and valleys. They both have mountains, too. Mars's mountains are a lot taller, though! Both of these planets also have volcanoes. While they are a lot alike, Mars and Earth are also very different. Mars is smaller and much colder than our planet. The average temperature on Mars is 80 degrees below zero! That is a lot colder than the North Pole! Mars also has two moons. Earth only has one. Our moon .....