Alright kiddo, let's imagine you're playing with some marbles. You might have a big one and a bunch of smaller ones, right? Now imagine that instead of marbles, we're talking about really, really big things: planets, asteroids, and other space rocks. That's what the solar system is made of!
A long, long time ago, before there were any people or animals on Earth, there was just a huge cloud of gas and dust floating around in space. This cloud was so big that it started to collapse in on itself because of gravity. When it collapsed, it started spinning, kind of like you spinning around while holding onto a merry-go-round at the park.
As this spinning cloud got smaller and smaller, it also started getting hotter and hotter in the middle. Eventually, the middle got so hot that it started glowing! That's what we call a star, and in this case, it's the star we know as the sun. The hot, glowing star at the center of the spinning cloud started pushing all of the gas and dust away, creating an area in the middle that was clear.
But all around that clear area, there were still a bunch of rocks and gas and dust whirling around. Over time, some of those rocks started sticking together because of gravity. They kept getting bigger and bigger until they became the planets we know today!
Some of the rocks didn't stick together and instead became asteroids, meteoroids, or comets. And all of this happened over billions of years! It's kind of like building a really, really big puzzle - but instead of having all the pieces ready to go, you have to wait for pieces to come together naturally over time.
So that's the story of how the solar system was formed! A big cloud of gas and dust collapsed in on itself, started spinning, formed a star in the middle, and then let the leftover stuff build into the planets, asteroids, and other space rocks that we can see today. Cool, huh?