Science Fiction or Real Mechanics? | StarTalk

We have a little quiz, a little game show. I want to know if this mechanical problem is a science fiction problem or a real-life, real mechanical problem? Bona fide mechanical problem. Real or not, is that right? Do we go bing or meh? Yes.

So is it a real thing in real life if you have a cracked harmonic balancer? Yeah, you can be cracked harmonic-- No, I would say it's science fiction. You harmonically balance a crankshaft and things. You're exactly right, it is a real car thing. The harmonic balancer is a device connected to the crankshaft of an engine to reduce torsional vibration and serves as a pulley for drive belts.

And now I have more questions than that actually answered. So what that means is-- because I pay attention to when I have to pay to get my car fixed. I've never broken my harmonic balancer. No. They're usually geared-- they're very high rel, high reliability. They're in an oil bath. But, Neal, you'll like this.

The rate of change of position is-- That's velocity. Rate of change of velocity is--

NEIL DEGRASSE TYSON: --acceleration. So the rate of change of acceleration--

--is a jerk. And that's what will make that go away.

NEIL DEGRASSE TYSON: OK, cool. Yeah. A little bit of physics stuff going on there. Yes.

All right, would it be a real-- Wait, just to be clear, so rate of change in position is speed, or velocity. And we've all familiar with being at a constant velocity. When you're at a constant velocity, you don't feel it.

So now, if you're accelerating and you've positioned yourself and all your muscles are resisting the constant acceleration, then you have a change in the acceleration. That's a jerk. So you feel it, and then you punch the brakes some more. Then you'll feel a jerk forward. That's why it's appropriately called a jerk.

So what else do you have? All right, what about defective planetary gears?

NEIL DEGRASSE TYSON: Sure. Defective planetary gears. Yeah, you have planetary gears, where you have a sun gear and planet gears. I didn't know anything about it. You have a three-speed bicycle, you have a planetary gear train.

NEIL DEGRASSE TYSON: Really? That is exactly it. They're the primary gears within an automatic transmission. OK, very good.

All right. What if you had an unmotivated binary motivator? That sounds like science fiction to me. So what is it?

You are straight-up correct. That is in "Star Wars." It's a device in droids. "Star Wars," OK. One more-- what if you had a damp flux capacitor?

That is of course, real. So that was a documentary called "Back to the Future." I highly recommended it. I think it's on Netflix.