How Long Is One Second, Really? Do we really know how long a second is? The science behind how time is actually measured may prove you wrong. Facebook Prev Article Next Article Discover Checkout these cool gadgets... Related Posts Which Way Is Down? – Vsauce Is Dust Mostly Dead Skin? German Scientists Just Tested NASA’s EM Drive… Does It Work Now? How to Make First Contact Earth Has an Underground Reservoir of Water Larger Than All Oceans Why Planes Don’t Fly Faster