Perhaps youâ€™ve noticed all the fuss this week over Albert Einstein and his famous general theory of relativity, which turned 100 years old. Who better to give you a glimpse into what the theory is all about than a Time Lord â€” the Tenth Doctor himself?

In this charming animation, David Tennant gives you a whirlwind tour of the key concepts of general relativity: objects with mass curve space-time, and this gives rise to what we feel as gravity. And since space and time are unified, if space can warp, so can time: the bigger the curvature, the slower time flows. In theory, at least, space-time can warp so much that wormholes can form, creating a shortcut connecting two otherwise distant parts of the universe. (The good Doctor knows all about that.)

Whatâ€™s nice about this particular video is that it doesnâ€™t stop there. General relativity might need a few tweaks in light of the 1998 discovery that not only is our universe expanding, itâ€™s expanding at an ever-increasing rate. Thatâ€™s why physicists today invoke dark energy and dark matter as a possible explanation consistent with the GRâ€™s predictions.

As Tennant notes, physicists have been putting general relativity to the test for a century now, and a new crop of experiments will put the theory to the test yet again, hopefully with definitive results. â€śIf it succeeds again, physicists will party. If they find its limits and it finally fails, theyâ€™ll party too. Physicists are funny like that.â€ť

Bonus: In his annual Thanksgiving post, Caltech physicist Sean Carroll gives thanks for the mathematical basis for curved space-time: Riemannian Geometry. Since weâ€™re celebrating the 100th anniversary of general relativity, he reasons, â€śit makes sense to honor the epochal advance in mathematics that directly enabled Einsteinâ€™s epochal advance in our understanding of space-time.â€ť

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