Why do some planets have rings?

JReid

The generally accepted theory is that ringed planets have sufficient gravity to attract and hold a lot of space debris that is left over from the matter that originally compressed to form the sun and its planetary system. It is also possible that the debris which we now see as rings was once part of a larger satellite(s) that was broken up either by collisions with other small bodies or by the constant gravitational stress exerted by the planet around which they circulate. The debris also tends to get flattened by the rotation, so we see it as rings many miles wide but less than a mile thick. Dec 14 00, 4:34 PM