Can you crush atoms?
Not normally, but there are certain types of stars, called neutron stars, that are made from 'crushed' atoms. The gravitational field is high enough in a neutron star that the electrons around an atom are forced to combine with the protons in the nucleus, creating neutrons. Imagine the sun squeezed into a sphere a few miles across. A teaspoon full of neutron star material would weigh several tons.
Also, black holes are the ultimate example of crushed atoms. According to the math, the matter which makes a black hole takes up no space at all...
Steve Gagnon, Science Education Specialist (Other answers by Steve Gagnon)