This week, extreme athlete Felix Baumgartner will embark on a 23-mile free fall, with the hope of breaking the sound barrier. What will he be facing? And what does falling feel like to the rest of us less-extreme athletes?

Peter, a listener from Rhode Island, went skydiving back in in his college days. He told us:

"My whole stomach, it went all the way up to my ears. My whole body just floated. You almost feel sick for a second, but then you realize you're not sick. Euphoria takes over, and it's just like, it's probably like 90 percent happy for that second and 10 percent scared, for that one second or that five second period you have of free falling, before your shoot opens. It's probably the greatest part of the whole thing."

Peter didn't jump tandem. He did it all by himself. And he only did it once.

Jen Sharp has a different kind of relationship with falling. She hasn’t done it once, but over 3,000 times, frequently with a novice strapped to her. She’s a skydiving instructor and co-founder of Female Skydiving Instructors, a networking organization. 

"There's a depth perception illusion, actually, we call it the distance illusion," Sharp says. "The same thing happens when you're driving a car. You look off in the distance, and that farm house off in the distance isn't moving at all, but the grass right next to your car is moving really fast. So you don't actually sense speed until you're close to it, so the perception of free fall — we don't actually feel like we're falling because there's no acceleration, we're at a constant rate — and the ground is so far away, even at 10,000 feet, even at 6,000 feet, that you don't notice that you're moving towards it."

"You just feel like you're flying," Sharp says. "It doesn't feel like falling at all."

"At 10,000 feet, everything looks small, including your problems. You just are really right in the moment." Sharp says this is the best part about being a skydiver, because it teaches you to be present, and not think too much about the past or future, even in your daily life. 

"We can't wait for it to happen," Jen Sharp says of the 23-mile free fall that Baumgartner will attempt.