Heavyweight division

摘要

At the modest temperatures and pressures of Earth's surface, the densest known material is the metallic element osmium, which packs 22 grams into 1 cubic centimetre, or more than 100 grams into a teaspoonful. Even osmium is full of fluff, however, in theform of electron clouds that separate the dense atomic nuclei. Although rarefied, these clouds are robust, and even the immense pressures deep within the planet can only compress solid matter to a modest degree.