Asteroids And ETs

A new search strategy for finding extraterrestrial civilizations that have spread into space involves studying the asteroid populations around other stars. The premise is that as a civilization enters space it will use asteroids as a physical resource, and we might be able to detect a difference between a natural asteroid population and one that is being exploited for industrial use. For example, a lack of industrial metals in asteroids could suggest mining. Similarly, scarcity of large asteroids could imply a civilization found it more economical to mine and disassemble large bodies, thus leaving only smaller asteroids. Unusual heat in an asteroid belt could also mean industrial activity. None of those would be proof of ET, but-- especially if all three are found in the same solar system-- such indications could be flags telling us to look closer.