Thank you for The Great Courses Plus for Supporting PBS. To learn more and try The Great Courses Plus click, http://ow.ly/ORgD30rA2tQ.

PBS Member Stations rely on viewers like you. To support your local station, go to: http://to.pbs.org/DonateSPACE

Sign Up on Patreon to get access to the Space Time Discord!
  / pbsspacetime  

“A moving arrow is at rest.” This is obviously a nonsensical contradiction. But Zeno, a Greek philosopher famous for his metaphysical trolling, devised a paradox whose conclusion is just this. Here’s how it goes: if you look at an arrow flying through the air at any instantaneous snapshot in time, the arrow doesn’t travel any distance. If time is composed of an infinite number of these snapshots, and the arrow doesn’t move in any of them, then the arrow is at rest during the entirety of its flight. The moving arrow is at rest.

In fact, if we’re talking about a quantum arrow, there may be a way to freeze its motion simply by looking at it, through the aptly named quantum Zeno effect. The quantum Zeno effect predicts that certain quantum events - like the electrons moving between atomic energy levels, or the decay of atomic nuclei, can be frozen through the simple act of observation. I’m going to tell you about some very real experiments that claim to have demonstrated this phenomenon. But first, let’s see if the quantum Zeno effect can save us from being shot by a quantum arrow.

Check out the Space Time Merch Store
https://www.pbsspacetime.com

Sign up for the mailing list to get episode notifications and hear special announcements!
https://mailchi.mp/1a6eb8f2717d/space...

Hosted by Matt O'Dowd
Written by Katie McCormick & Matt O'Dowd
Graphics by Leonardo Scholzer, Yago Ballarini, Pedro Osinski, Adriano Leal & Stephanie Faria
GFX Visualizations: Katherine Kornei
Directed by Andrew Kornhaber
Assistant Producer: Setare Gholipour
Executive Producers: Eric Brown & Andrew Kornhaber

End Credits Music by J.R.S. Schattenberg:    / @jrsschattenberg  

Special Thanks to Our Supporters on Patreon!

Big Bang Supporters
Brian Scott
Rick DeWitt
Sandy Wu
Matthew Miller
Brodie Rao
Scott Gray
Ahmad Jodeh
Radu Negulescu
Alexander Tamas
Morgan Hough
Juan Benet
Vinnie Falco
Fabrice Eap
Mark Rosenthal
David Nicklas

Quasar Supporters
Hank S
Christina Oegren
Mark Heising

Hypernova Supporters
William Bryan
Rich Hammons
Scott Gorlick
Nick Berard
Paul Stehr-Green
Leo Emerson
muOn Marketing
Russell Pope
Ben Delo
L. Wayne Ausbrooks
Nicholas Newlin
Adrian Posor
Mark Matthew Bosko
Антон Кочков
John R. Slavik
Mathew
Danton Spivey
Donal Botkin
John Pollock
Edmund Fokschaner
Joseph Salomone
Matthew O'Connor
chuck zegar
Jordan Young
m0nk
John Hofmann
Timothy McCulloch

Gamma Ray Burst Supporters
Alexey Kamenskiy
Andrew Macleod
Diana S
Douglas Drane
Ben Campbell
Lawrence Tholl, DVM
Faraz Khan
Almog Cohen
Alex Edwards
Nick
Ádám Kettinger
Sylvain Leduc
Anthony Kahng
MD3
Endre Pech
Daniel Jennings
Cameron Sampson
Pratik Mukherjee
Geoffrey Clarion
Nate
Darren Duncan
Lily kawaii
Russ Creech
Jeremy Reed
Derek Davis
Eric Webster
Steven Sartore
David Johnston
J. King
Michael Barton
Christopher Barron
James Ramsey
Drew Hart
Justin Jermyn
Mr T
Andrew Mann
Jeremiah Johnson
fieldsa eleanory
Peter Mertz
Kevin O'Connell
Richard Deighton
Isaac Suttell
Devon Rosenthal
Oliver Flanagan
Dawn M Fink
Bleys Goodson
Darryl J Lyle
Robert Walter
Bruce B
Ismael Montecel
Simon Oliphant
Mirik Gogri
Mark Daniel Cohen
Brandon Lattin
Nickolas Andrew Freeman
Shane Calimlim
Tybie Fitzhugh
Robert Ilardi
Astaurus
Eric Kiebler
Craig Stonaha
Martin Skans
Michael Conroy
Graydon Goss
Frederic Simon
Tonyface
John Robinson
A G
Kevin Lee
Adrian Hatch
Yurii Konovaliuk
John Funai
Cass Costello
Geoffrey Short
Bradley Jenkins
Kyle Hofer
Tim Stephani
Luaan
AlecZero
Vlad Shipulin
Cody
Malte Ubl
King Zeckendorff
Nick Virtue
Scott Gossett
Martin J Lollar
Dan Warren
Patrick Sutton
John Griffith
Daniel Lyons
DFaulk
GrowingViolet
Kevin Warne
Andreas Nautsch
Brandon labonte