We could use laser light to mask our transits across the sun and thus hide Earth from any intelligent aliens looking for planets to invade
http://www.scientificamerican.com/podcast/episode/lasers-could-hide-earth-from-prying-aliens/
We could use laser light to mask our transits across the sun and thus hide Earth from any intelligent aliens looking for planets to invade
http://www.scientificamerican.com/podcast/episode/lasers-could-hide-earth-from-prying-aliens/