Earth's Mass and Motion Warps Spacetime as Einstein Said

An experiment conceived a half century ago has confirmed Einstein's general relativity predictions of the spacetime effects of Earth's mass and spin. Karen Hopkin reports

Illustration of a Bohr atom model spinning around the words Science Quickly with various science and medicine related icons around the text

Join Our Community of Science Lovers!

Albert Einstein wins again. A new study has confirmed another prediction of his theory of general relativity. The corroboration appears online in the journal Physical Review Letters. [Francis Everitt et al., citation to come.]

Einstein’s theory recognizes that massive objects warp the very fabric of space and time. If the theory is true, then the Earth should stretch the spacetime in which it sits, like a bowling ball would deform a trampoline. What’s more, the Earth’s rotation should also produce a drag on local spacetime, like a marble spinning in molasses would pull the goop around it.

To measure these minor deformations, scientists sent four gyroscopes into space in a mission called Gravity Probe B. And they found that after circling the Earth some 5000 times the gyroscopes’ angle of spin had changed, ever-so-slightly, in response to the Earth’s gravitational pull. Which proves that the old man was right.

Gravity Probe B was first conceived in 1959. [1976 paper envisioning the experimental setup] And the technology created to make the mission fly has been applied in work on the big bang theory—the real theory, not the TV show—and in GPS. Which Einstein would have loved. Because even a genius can get lost on the highway.

—Karen Hopkin

[The above text is an exact transcript of this podcast.]


On supporting science journalism

If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.


To see a lecture by Gravity Probe B principal investigator Francis Everitt go to http://einstein.stanford.edu/Media/Everitt_Brainstorm-flash.html

 

It’s Time to Stand Up for Science

If you enjoyed this article, I’d like to ask for your support. Scientific American has served as an advocate for science and industry for 180 years, and right now may be the most critical moment in that two-century history.

I’ve been a Scientific American subscriber since I was 12 years old, and it helped shape the way I look at the world. SciAm always educates and delights me, and inspires a sense of awe for our vast, beautiful universe. I hope it does that for you, too.

If you subscribe to Scientific American, you help ensure that our coverage is centered on meaningful research and discovery; that we have the resources to report on the decisions that threaten labs across the U.S.; and that we support both budding and working scientists at a time when the value of science itself too often goes unrecognized.

In return, you get essential news, captivating podcasts, brilliant infographics, can't-miss newsletters, must-watch videos, challenging games, and the science world's best writing and reporting. You can even gift someone a subscription.

There has never been a more important time for us to stand up and show why science matters. I hope you’ll support us in that mission.

Thank you,

David M. Ewalt, Editor in Chief, Scientific American

Subscribe