Hello, SFIA audio listeners, in this month's Nebula exclusive, Big Alien Theory,

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

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In an ancient and vast universe, we often wonder where all the aliens are, but just as

concerning as where all their ancient and vast artifacts are.

So today we are returning to the topic of the Farmy paradox, the big question of where all the aliens are,

when we live in a universe that is so enormous and old.

It seems hard to believe it shouldn't have spawned billions of civilizations by now.

Now, what we really mean is, why aren't we hearing communications from them,

and why aren't we seeing the signs of vast and ancient empires? Where are these empires?

And if they no longer resist, where are the ruins of them? Where are their pyramids or stonehenge,

so to speak? And to be fair,? Where are their pyramids, or Stonehenge, so to speak?

And to be fair, many folks think the pyramids or Stonehenge are examples of alien work themselves,

but in this context, we're talking about megastructures, the sorts of things that dwarf even the Great Pyramid,

and which can include examples that would dwarf even a planet, things we could astronomically see, either by their sheer enormity or by their sheer quantity.

So I thought today we would examine these apparently absent megastructures from a few perspectives.

If they are actually missing, or if we are seeing them but just

not recognizing them as artificial, if they are abundant but not where we expect, like if civilizations

...