Hello, SFIA audio listeners. In this month's Nebula exclusive, big alien theory,

we're asked at the reason alien civilizations might be rare is because most aliens are huge.

To hear it and every episode early and add free, plus hours of bonus content,

check out go.nebola.tv slash Isaac Arthur and use my code, Isaac Arthur.

A key criticism of our search for extraterrestrial intelligence, or SETI, is that we

might be looking in the wrong places, the wrong type of stars or planets, or that we should

be investigating sightings here on Earth.

But what if the easiest place to find aliens is to look in the mirror?

So today is our monthly sci-fi Sunday here on SFIA, where we look at concepts better

known from sci-fi than science and ask how realistic they are, or if science allows any

pathway to a given technology or situation.

And today we are also making a long-awaited return to our Alien Civilization series, as it's

been over 40 episodes since

our last entry in the series, Hungry Aliens, back in the spring. So I thought it was past

time for a return, and when one of our audience members suggested this to me, I didn't even put

in one of our audience image pools, I just stuck it right on the schedule, because it's a topic that is long overdue. Because there's very few topics that come up in regard

to aliens more often than that we are in some way related to them, that we are a lost colony,

or that they've visited us and bred with us, or that they're doing it now to create some hybrid

race, and we'll discuss those all today

and more.

Now our Alien Siv series is a somewhat tongue-in-cheek twin to our Formy Paradox series,

as what we do in Alien Sives is mostly to take a proposed behavior of aliens and try

...