What is the coldest planet in the solar system? A challenging question to ask your kids when it comes to the solar system planets and their facts. Will they give you the right answer? There are nine planets in the solar system and this is sometimes the only piece of information known by the kids and knowing their placement around the sun is another thing they might be well aware of, but not all of them know which is the biggest planet and which is the smallest or such kind of information. Knowing more about the solar system and its planets is one beneficial step to take while educating and homeschooling your kids, it could happen through telling them stories, reading them these stories or else giving them the permission to watch some educational videos that will provide them with the kind of information you want them to know about.