Massive lunar lava tubes (natural volcanic features) could be structurally sound enough to hold entire cities on the moon, according to a theoretical study presented by Purdue University scientists at the Lunar and Planetary Science Conference.

Here on Earth, we’re protected by a thick atmosphere and magnetic field, but the Moon lacks those features. Without this protection, temperatures can swing by 500 F throughout the day, there’s no shielding from cosmic radiation, and there’s no atmosphere to burn up meteors.

Philadelphia inside a theoretical lunar lava tube. Image: Purdue University. Image 1.Philadelphia inside a theoretical lunar lava tube. Image: Purdue University

The lava tubes are natural volcanic features when the edges cool to form a crust around a flowing river of lava. Once the flow stops, the pipe drains and cools into a tube. This crust, forms a layer that could protect future lunar colonists from the dangers of the moon. Using computer modeling and existing data, their examination shows that, in the low lunar gravity, lava tubes several miles wide could form underground. Researchers are now searching for evidence of these tunnels from spacecraft data.