http://setiathome.berkeley.edu/ap_prbh.php

‘When a huge star runs out of fuel, it collapses and then explodes in a supernova. What’s left over is a massive but relatively small object called a black hole. To give you an idea of a black hole’s density: the sun has a radius of 700,000 km. A black hole that weighs as much as the sun would have a radius of 3 km. If you could fill a typical Diet Coke pop can (12 oz) with the material in such a black hole, the can would weigh 7 trillion tons, almost as much as the weight of the water in Lake Superior.’