Lunar lava tube Lunar lava tube Lunar lava tubes are sub-surface tunnels on the Moon that are believed to have formed during basaltic lava flows. When the surface of a lava tube cools, it forms a hardened lid that contains the ongoing lava flow beneath the surface in a conduit-shaped passage. Once the flow of lava diminishes, the tunnel may become drained, forming a hollow void. Lunar lava tubes are formed on surfaces that have a slope that ranges in angle from 0.4° to 6.5°. Lunar lava tubes may be as wide as before they become unstable against gravitational collapse. However, stable tubes
Lava lava tubes where the minimal heat loss maintains low viscosity. The surface texture of pāhoehoe flows varies widely, displaying all kinds of bizarre shapes often referred to as lava sculpture. With increasing distance from the source, pāhoehoe flows may change into aā flows in response to heat loss and consequent increase in viscosity. Pahoehoe lavas typically have a temperature of . On the Earth, most lava flows are less than long, but some pāhoehoe flows are more than long. The rounded texture makes pāhoehoe a poor radar reflector, and is difficult to see from an orbiting satellite (dark on Magellan