What if the answer to why we don't hear from alien civilizations is floating around us every day?

Today, we will dive into the atmospheric mysteries that might explain the great silence of the universe.

Welcome back to Science and Futurism with Isaac Arthur for another look at the Fermi paradox, the big question

of where all the aliens are. Often, we reason along the lines that those ancient alien civilizations

we would expect to exist simply do not, and that there are a lot of hard steps on the road

from inanimate stardust gathering to form our planets, and evolving

life on that planet that one day can build rockets to escape that planet, and settle

new ones.

We call those hard steps filters, hurdles that must be passed on the road to the stars,

and they can be everything from what makes a planet

hospitable to life, to that life evolving a complex brain and tool use.

Today we'll be looking at a neglected filter, the role of atmospheres and air retention

in the Fermi paradox and Earth's origins.

Everyone knows it's important to have air, but it's a surprisingly complex

topic and also a surprisingly under-discussed one. None sing hymns to breath, but oh,

to be without it, says Yama, the incarnation of death in Roger Zlazny's classic sci-fi novel,

Lord of Light, after drowning in an opponent

who seemed immune to all his other attacks.

It's a truly epic novel, set in a distant and isolated colony of Earth in an equally

distant future of advanced technology that blurs the lines between science and magic

at times, where the ancient settlers of that planet,

who fought to make it livable, live on still, in our world, peopled by their technologically

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