* Solar systems form from the leftover material around a star. After a star forms, there's often a disk of gas and dust left over. This material can clump together, forming planets, moons, asteroids, and other objects.
* Stars vary in size and mass. Smaller, less massive stars may not have enough leftover material to form a solar system.
* The environment around a star is important. If a star is in a crowded region of space, it's more likely to be disturbed, making it less likely for a solar system to form.
So, while many stars likely have planets orbiting them, not every star does. Our understanding of planet formation is still evolving, and we're constantly discovering new exoplanets around other stars.
