We live in a galaxy with between 100 billion and 400 billion stars, each potentially surrounded by planets...[N]ew NASA research indicates there are probably at least [2,000 billion galaxies in our observable universe].
So, as the Nobel Prize-winning physicist Enrico Fermi famously asked of our alien neighbors, "Where are they?"
One hypothesis is that before intelligent life manages to spread beyond its original planet to other nearby planets, it runs into a sort of "Great Filter."
As the philosopher Nick Bostrom explains, this idea suggests there are several "evolutionary transitions or steps" that life on an Earth-like planet has to achieve before it can communicate with civilizations in other star systems.
Climate change caused by the development of advanced civilization could very well be that filter in our case. David Wallace-Wells suggested this possibility in a recent feature:
"In a universe that is many billions of years old,...civilizations might emerge and develop and burn themselves up simply too fast to ever find one another...The mass extinction we are now living through has only just begun; so much more dying is coming."
The GLP aggregated and excerpted this blog/article to reflect the diversity of news, opinion, and analysis. Read full, original post: There's a compelling reason scientists think we've never found aliens, and it suggests humans are already going extinct