Free Astronomy Magazine May-June 2018

6 MAY-JUNE 2018 to severely affect any form of life not ade- quately sheltered. The same is true for mete- orites that, like bullets, impact the lunar surface without braking. The rarefied martian at- mosphere provides little protection, capable of only disintegrating mete- orites within certain lim- its of mass and composi- tion. It is conceivable that a permanent human set- tlement either on the Moon or Mars could effi- ciently shield its inhabi- tants from both harmful radiation and sudden changes in temperature between day and night, but very little could be done against the impact of meteorites with even modest masses. Many readers have certainly seen the photographs of those shimmering metallic meteorites that the martian rovers have encountered along their journeys. They are tens of centimeters wide and several kilo- grams in weight: what would happen if an object of that type fell on an inhabited settle- ment? The priority of the fu- ture colonization of the solar system’s plan- etary bodies will, therefore, be to pro- tect the bases from un- ceasing solar radiation and the occasional (but probable in the long term) impact of smaller meteorites. One of the solutions in colonization proposals that has become in- creasingly familiar in recent years is to cover the bases, at least T he Marius Hills pit is a possible skylight in a lava tube in an ancient volcanic region of the Moon called the Marius Hills. This LROC image is the highest resolu- tion image of the pit to date. Image width is 1200 me- ters. [NASA/GSFC/ Arizona State University] Left, images of the Marius Hills pit as observed under dif- ferent solar illumi- nation conditions by the SELENE/ Kaguya Terrain Camera and Multi- band Imager. [JAXA/SELENE]