Your gateway to endless inspiration
The Search for Evidence of Space_Mining Operations in Other Solar_Systems.
One interesting way for Astronomers to search for Extra_Solar Civilizations and/or Extra_Solar Alien_Technology is to search for Chemical Signatures of Advanced Alien_Technology like:
Chlorofluorocarbons.
Here's a Good Look at Alien Aerospace Engineering.
This is part two of a Science Documentary about: UFO Propulsion.