Question

Astronomical observation from moon surface vis-a-vis low earth orbiting observatory? Which one is better for Astrobiology study?

The interest of astronomers in lunar astronomical observatories has changed over time. There are many advantages to building observatories in space, such as access to much more of the spectrum of electromagnetic radiation. Several decades ago, the Moon seemed like an ideal platform for an observatory, especially if humans were living on the Moon to service it. More recently, however, opinion has shifted. We are concerned about lunar dust, which could degrade the optics. And we have learned to appreciate the advantages of telescopes in space, which can be pointed precisely and work extremely well in the absence of gravity. However, for most purposes the best place for such telescopes is not low Earth orbit, but a heliocentric orbit, perhaps at one of the quasi-stable Langrangian points. What is true for astronomy in general is also true for astrobiology. The one major exception is in radio astronomy, especially the search for the very faint signals of extraterrestrial civilizations. The ideal place for an advanced SETI observatory would be on the far side of the Moon, where it would be shielded from radio sources on the Earth. David Morrison
NAI Senior Scientist
July 2, 2007