The Cosmos


Video: What is Gravity Made Of?

Editor’s note: New data have cast doubt on the interpretation of the BICEP2 data. For an update on this story, read Inflation, Elation, Deflation: Reflecting on BICEP2.

One of the most incredible physics discoveries of the century was just made. It reveals new secrets of gravity and the birth of our universe, called “inflation.” This video takes us back to the beginning of time and explains how quantum particles in the infant universe created a cosmic fingerprint that scientists can see today. This new evidence tells not only why the universe exploded outward during its birth, but also that gravity is made of quantum particles, called gravitons.

Go Deeper
Editor’s picks for further reading

BICEP2: 2014 Results Release
On the BICEP2 project page, find links to the original papers covering BICEP2’s results as well as FAQs, data products, and informational videos.

Kavli Foundation: Spotlight Live: The Universe’s First Light
In this video chat, John Carlstrom, Walter Ogburn, Michael Turner and Abigail Vieregg discuss the BICEP2 data and their implications.

Physicsworld: Neil Turok urges caution on BICEP2 results
Physicsworld strikes a rarely heard note of skepticism on the BICEP2 detection.

Tell us what you think on Twitter, Facebook, or email.

Greg Kestin

    Greg Kestin holds a faculty position at Harvard University, where he conducts theoretical physics research, teaches, and produces educational online content. He earned his physics Ph.D. from Harvard, as a member of The Center for the Fundamental Laws of Nature, focusing on theoretical particle physics and quantum field theory. Over his career, he has also conducted research in nuclear physics, fusion energy, and gravitational wave physics. For over a decade he has been involved with innovative educational outreach endeavors, bringing science to both students and members of the public through his writings, videos, lectures, and multimedia.

    • A particle physics student(!) trying to steal what’s likely the most important discovery of all times. And since PBS publishes it, this is obviously being done for this kid’s bosses sakes — particle physicists — who have no balls to do it on their own so they’re launching this kid as a sort of low-orbiting satellite to do the recon. But the discovery according to the discoverer himself (Linde) requires/allows for both Multiverse and strings. Says the student – no, it was graviton all the time! What audacity, even if from the biggest scientific mob ever.

      • sr

        And you know all this how? A tad overwrought over a simple informative video aren’t you!

        • Ah, those little birds…

          • luke

            I agree with you, show me the math and then I will concur.

    • Dan Bunbury

      Surprised this video is still available, or at least without an addendum, as this ‘discovery’ has since been discredited (

    • Chris

      Wow, wrong! But a nicely produced video….

      • Rebecca Clare Scott

        Why do you think it is wrong?