There are plenty of things scientists don’t understand about the universe, but for everyday folks, some of the biggest misconceptions are about the basics: time and size. Neil deGrasse Tyson, the world-famous astrophysicist, director of the Hayden Planetarium in New York and host of the “StarTalk” podcast and TV show, tried to break them down in the clip above. The video was initially posted by Tech Insider last year, but it went viral again. Perhaps people are looking for reassurance that four years isn’t such a long time ― at least on a cosmic scale.