Today I learned...

Post things you learned today, or recently. They can be interesting bits of information, they can be life lessons, or anything in between.
 

 
Today I learned that “Escape velocity” isn’t the speed needed to just leave a planet/moon. It’s the speed you need to travel at to be completely unaffected by an object’s gravity.

I recently learned the closed and recursive formulae to calculate the nth term in the triangular number series.

TIL that ketchup shouldn’t go on eggs.