Every once in a while we add a second onto our days. Similar to the Leap Year, this is known as the Leap Second. But, if the Leap Year already helps us account for the offset from a calendar in days, what exactly does the Leap Second do? Check out this video for the answer!

Last time we talked about what curvature means, looked at geodesics, great circles on spheres, and tried to understand the notion of "straightness". This week on Spacetime, we take a detour into how geometry works in spacetime. Get excited, because this episode is even more mind-bending than the last!

We've been through the first few episodes of our crash course on general relativity, and came out alive! But it's officially "time" for CURVED spacetime. Join Gabe on this week’s episode of PBS Space Time as he discusses Newton and Einstein's dispute over inertial frames of reference. Is Einstein's theory inconsistent? Is gravity even a force??? Check out the episode to find out!

We all know tides have something to do with gravity from the Moon and Sun, but if gravity affects the motion of all objects equally, then how come oceans have large tides while other bodies of water don't? It's because your mental picture of the tides is probably WRONG!

Black holes! From Stephen Hawking to Interstellar, black holes are mammoths in the world of science AND sci-fi. But what exactly IS a black hole? Do events happen inside black holes? Are black holes really a hole? Are black holes really black?!