LOCATING LUNAR SUBWAYS

摘要

Billions of years ago, volcanoes erupted on the Moon. Molten rock spewed up and onto the surface, then spread out and flowed down into deep basins and craters left by ancient impacts. The lava flowed on and off for millennia, filling and then overflowing cra ters in its drive to find the lowest ground.Some lava melted the rock underneath it, carving channels like river beds down hills and into valleys. Gases bubbled up out of the lava and escaped into the vacuum of space, rapidly cooling the surface of the channels. Like a river icing over, a hard crust formed. This crust insulated the lava underneath, keeping it molten and flowing.As the eruptions subsided, lava drained out the ends of some of these channels, leaving hollow lava tubes that snake along for miles under the surface, hidden from view.Over the eons, the relentless tug of gravity and the stress of impacts have caused some tunnel ceilings to collapse, opening pits called skylights. Although scientists had identified some potential locations of lava tubes on the Moon, the discovery of the first skylight in 2009 was the first proof of their existence. Unfortunately, even eagle-eyed spacecraft have a hard time spotting these small dark pits in the cratered lunar surface.University of Texas-El Paso grad student Jon Meyer is working on an easier way to locate lava tubes than searching for tiny skylights. "What's really operationally fulfilling is the uncollapsed portions of the tube. Those habitats could protect from micro-meteorite bombardment, radiation, and diurnal temperature fluctuation that happen on the Moon," Meyer said in a recent interview.