Are Humans Alone In The Universe? Ancient Alien Civilizations May Have Previously Existed
Are humans alone in the universe? Scientists have taken a closer look and found that other, advanced civilizations may have existed in the past.
Are humans alone in the universe? Scientists have taken a closer look and found that other, advanced civilizations may have existed in the past. (Photo : Wikimedia Commons)
Are humans alone in the universe, or is there intelligent life out there somewhere? Scientists have taken another look and found that recent discoveries of exoplanets combined with a broader approach to the question makes it possible to assign a new empirically valid probability to whether any other advanced civilizations have ever existed.
"The question of whether advanced civilizations exist elsewhere in the universe has always been vexed with three large uncertainties in the Drake equation," said Adam Frank of the University of Rochester and co-author of the new study. "We've known for a long time approximately how many stars exist. We didn't know how many of those stars had planets that could potentially harbor life, how often life might evolve and lead to intelligent beings, and how long any civilizations might last before becoming extinct."
NASA's Kepler satellite and other planetary searches have shown that roughly one-fifth of stars have planets that are in the "habitable" zone. This zone is where temperatures could potentially support life as we know it. But more interesting is the question of how long civilizations might survive on possibly habitable planets. Read More >>