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.t.v.t.v. And use my code, Isaac Arthur.

When we talk about the origin of the universe, most of us picture the Big Bang, a singular

titanic event from which all space, time, matter, and energy births forth.

It's the leading theory, the model that has shaped our understanding of cosmos for nearly

a century, from textbooks to pop culture, the Big Bang

reigns supreme. But science is not about clean to sacred cows. It's about constantly

testing our ideas no matter how well loved they are. So today, let's pose a dangerous

question. What if the Big Bang never happened? What if the universe did not spring

from a singular explosion 13.8 billion years ago? What if everything we think we know

about the beginning is the story we told ourselves, a story that could someday be replaced?

And what might replace it? In this episode, we'll look at the best reasons

we have for believing in the Big Bang, and some of the best reasons to doubt it. We'll dive

into competing models, both classic and cutting edge, that offer different visions of how the

universe might have come to be, or might always have been, And along the way, we'll wrestle with some of the

most fundamental questions science can ask. Did the universe have a beginning at all, or has it

always existed? So, grab a drink and a snack, and let's journey back not just the dawn of time,

but beyond it, to a place where beginnings and innings might not even exist.

Why do we believe in the Big Bang? For all of its strangeness, the Big Bang isn't just a shot

in the dark. It rests on three major pillars of observational evidence, pillars that are,

...