Jupiter, the largest planet in the solar system, is composed of hydrogen and helium. These are the same elements that our Sun is made up of. However, Jupiter is not large enough to start nuclear fusion and generate its own energy. If it were around 80 times bigger, it would become a star with low mass.
Another fun fact about Jupiter is that it has a storm called the Great Red Spot. It has been swirling for more than a hundred years.