In 1915, a 36-year old physicist named Albert Einstein published a paper on the theory of general relativity, which posits that gravity between objects is caused by curvatures in space and time (hence, "spacetime"). It's not that Isaac Newton's law was entirely wrong, per se, but he didn't have the whole story.
This week marks the 100th anniversary of Einstein's work, and to celebrate, animator Eoin Duffy and a team of writers / producers created this three-minute video explaining what general relativity is and why it matters. What the video lacks in nitty-gritty details, it makes up in charm, with narration provided by David Tennant (Doctor Who). It's wonderful to hear the Tenth Doctor utter words like "spacetime" and "dark energy" — and for Jessica Jones binge-watchers, it's nice to take a moment and remember that Tennant can also use his voice as a force for good.
It's unlikely the foundation of modern physics will be brought up over Thanksgiving dinner — not before VR or Adele, at least — but if you're looking for a fun read, check out Einstein's original transcript or at least the introductory Wikipedia page.
Correction: An earlier version of this article stated that Einstein was 26 in 1915. He was, in fact, 36 at the time (though he might've looked really good for his age; that's subjective).