What are the main differences between stellar black holes and supermassive black holes?
Stellar black holes are formed in the cores of giant stars whereas supermassive black holes form in the center of galaxies and stay there.
Supermassive black holes are ENORMOUS, and can stretch for nearly 2 billion miles! Stellar black holes however, are much smaller and stretch around 20-100 miles across. They roam around the emptiness of space, devouring stars. Supermassive black holes stay in the center of galaxies and hold it together.