All About Cosmic Inflation

What everyone should know about where our matter-and-radiation-filled Universe came from.

“I don’t think at this point we have any way of knowing where the laws of physics came from. We could hope that when we really understand the laws of physics that they will describe how the Universe came into existence.”
-Alan Guth

There’s a flurry of information coming out about the Big Bang and inflation, from bloggers, news outlets, science publications and scientists themselves. The wikipedia page on inflation is being rapidly updated as well, and misconceptions and misunderstandings are flying around, far outnumbering the rare sources that get the majority of the story right. In the aftermath of the release of the foundation-shaking results of the BICEP2 collaboration, there’s now a great opportunity for the world to understand exactly what we know about the origin of the Universe, how it developed, and — if the new discovery stands up to independent confirmation — what we will have learned.

Let’s start at the beginning.

An image of the Milky Way from ESO’s La Silla Observatory. (Y. Beletsky)

In the early 20th century, our understanding of the Universe underwent a number of…