Want to Make a Volcano Explode? Just Add Heat

Volcanoes erupt explosively when gas-charged magma reaches Earth's surface. The formation and growth of gas bubbles are complex processes that fascinate nearly every volcanologist. There are volcanologists who peer inside tiny crystals to measure minuscule amounts of dissolved gas, and there are volcanologists who use spectroscopy — specifically studies of how minerals absorb ultraviolet light — to measure the copious gases billowing from a vent.