One explanation that scientists explored at the METI meeting, is that aliens are aware of Earth and are observing us as we would observe animals kept in a zoo, METI President Douglas Vakoch said in a workshop. If this is the case, humans should increase their efforts to create messages capable of reaching our "keepers," to demonstrate our intelligence, Vakoch explained.For example, if a captive zebra were to suddenly tap out a pattern of prime numbers, humans would be required to re-evaluate their understanding of zebra cognition, "and we would be compelled to respond," according to EarthSky.But what if we're...