Are You a Boltzmann Brain?

Viewers like you help make PBS (Thank you 😃) . Support your local PBS Member Station here

Was an incredible drop in entropy responsible for the Big Bang? If that’s the case, this would lead us to conclude that a great many other things are possible, including the likelihood that you are a Boltzmann Brain. Try The Great Courses Plus at

You can further support us on Patreon at

Get your own Space Time t­shirt at

Tweet at us! @pbsspacetime

Facebook: facebook.com/pbsspacetime

Email us! pbsspacetime [at] gmail [dot] com

Comment on Reddit

Help translate our videos!

Previous Episode:

The Oh My God Particle

The second Law of Thermodynamics tells us that everything moves towards a state of greater entropy, but it is low entropy that enables galaxies, stars, planets and human beings. The lowest entropy state that we’re aware of in our universe was right before the Big Bang. The entirety of our own universe was condensed to a microscopic size. What caused this extreme low entropy? If it was caused by a random fluctuation in particles that implies that a great many other things are possible due to the random fluctuations of particles. One of the strangest of those possibilities is that of the Boltzmann Brain. If the Big Bang was caused by random entropic fluctuations then it is much more likely you are a Boltzmann Brain than that you are a human being.

Written and Hosted by Matt O’Dowd

Produced by Rusty Ward

Graphics by Kurt Ross

Made by Kornhaber Brown (www.kornhaberbrown.com)

The Great Courses Plus is currently available to watch through a web browser to almost anyone in the world and optimized for the US market. The Great Courses Plus is currently working to both optimize the product globally and accept credit card payments globally.

Special thanks to our Patreon Big Bang, Quasar and Hypernova Supporters:

Big Bang

Shane Robinson

David Nicklas

Samuel Dean Jacintho

Quasar

Tambe Barsbay

Luna IT Solutions

Coolascats

Avan & Kyan Griggs

Max Levine

Hypernova

Science Via Markets

Chuck Zegar

Craig Peterson

Jordan Young

Ratfeast

John Hofmann

Thanks to our Patreon Gamma Ray Burst Supporters:

Justin Lloyd

Conor Dillon

Jared Moore

Michal-Peanut Karmi

Bernardo Higuera

Erik Stein

Daniel Lyons

Jade Bilkey

Kevin Warne

JJ Bagnell

J Rejc

Dylan Merida

Amy Jie

Anthony Caridi

Avi Goldfinger

John Pettit

Shannan Catalano

Florian Stinglmayr

Yubo Du

Benoit Pagé-Guitard

Ronny Polonia

Nathan Leniz

Jessica Fraley

Kirk Mathews

Loro Lukic

Carl P. Corliss

Brandon labonte

David Crane

Greg Weiss

Eric Jackson