Learn Black Holes with Me in 1 Week - Day 2

Added: 2026-06-03

[00:00:00]All right, this is day two of seven of learning black holes so my physicist boyfriend will buy me tickets to see Drake.

[00:00:06]Okay, no mouse in this drink, we're good. Yesterday we learned about gravity basics and stellar life cycles and today we're going into how stars actually die and then something called an escape velocity. Let's get into it. And make sure you hit follow if you love science content. So black holes are essentially caused by stars that die and whether or not the star actually becomes a black hole or not depends on one thing. How much mass is left behind? And scientists figured out that there is a hard limit.

[00:00:29]It's called the Tolman-Oppenheimer-Volkoff limit and it basically dictates that if the leftover core is more than three times the mass of the sun then it will form a black hole. Now, here's how to think about escape velocity. You throw a ball up in the air on Earth, it comes back down, but how can rockets actually escape? Every object in the universe has a speed that you need to surpass to escape it. For Earth, it's about 7 mi/s and we know the fastest speed known to Earth, woman, man is the speed of light.

[00:00:53]Basically, a black hole is just an object that is so dense that the escape velocity needed to escape it is faster than the speed of light, which is not possible. So that's why it's a bottomless pit and nothing ever gets out. Boundary where light can no longer escape is called the event horizon and we'll learn about that tomorrow, but if you want to access the full course now, you can comment black hole and I'll send you the entire course I learned this in 15 minutes.