Lava is the
molten rock expelled by a
volcano during an
eruption. The resulting rock after solidification and cooling is also called lava. The molten rock is formed in the interior of some
planets, including
Earth, and some of their
satellites. The source of the heat that melts the rock within the earth is
geothermal energy. When first erupted from a volcanic vent, lava is a
liquid at
temperatures from .