One of my favorite fun facts is that if you were to dig a frictionless borehole to the other side of the world, you could hope in, be accelerated towards the center of the earth, decelerate on your way up to the other side, and pop out with 0 velocity 42 minutes later.
Now, this is the fun part, the 42 minute time frame is true for using gravity to coast through a straight hole between any two locations on Earth's surface!
(Assuming a perfectly uniform density sphere and no friction on your journey of course)
It’s fun to think about, but frictionless means you’d have to pump out the air. So you’d need to wear a space suit, and heat shielding. It’s kinda hot down there.
Now, this is the fun part, the 42 minute time frame is true for using gravity to coast through a straight hole between any two locations on Earth's surface!
(Assuming a perfectly uniform density sphere and no friction on your journey of course)