# Science Fiction or Real Mechanics? | StarTalk

We have a little quiz,
a little game show. I want to know with 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:
–accerlation. 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.