Why Pitchers Would Hate to Play Baseball In Outer Space

PITTSBURGH – From June to November 2011, Satoshi Furukawa, an astronaut with the Japan Aerospace Exploration Agency, stayed aboard the International Space Station for 165 days as a flight engineer for the Expedition 28/29 mission. His mission included experiments in Kibo, and ISS maintenance as well as playing a one-man game of baseball, which we can see in in the above video.¹

While it certainly appears Dr. Furukawa is having a blast playing baseball aboard the ISS, his simple back-and-forth, one-man game can teach us a lot about the intricacies of the game, specifically from a pitching point of view and why playing baseball in space as opposed to playing it on earth would make things so much more difficult for a pitcher.

Let’s explore…

Below is a series of data charts from the MLB StatCast Twitter account, detailing and explaining the spin rate of MLB pitches. The first three charts give us the spin rate of eight(!) different pitches, measured in revolutions per minute (rpm), coupled with each pitch’s velocity in miles per hour (mph). The fourth and last StatCast chart shows us the batted ball outcome of five different pitches, relative to spin rate.

While this is definitely fun and very useful and interesting data, Diamond Kinetics’ Technical Advisor Dr. Alan Nathan points out a very important addendum, relative to – as he puts it – “useful” spin versus total spin.

In his March 31, 2015 piece for Baseball Prospectus entitled, “All Spin Is Not Alike”, Dr. Nathan tells us:

“The reason has to do with the vector nature of the spin: It has a magnitude and a direction. The magnitude is pretty simple, since it is just the number of revolutions per minute, or rpm. Let’s talk about the direction. The easiest way to determine the direction of the spin is to use a right-hand rule: Wrap the fingers of your right hand around the ball so that they point in the direction that the ball is turning. Your thumb will then point in the direction of the spin axis.”

But what happens if there is little to no spin on a ball?

This is the issue that pitchers would face if baseball was indeed played in outer space. As we learned in July of last year, Magnus Force (or the Magnus Effect) has a pronounced effect on the spin of a pitch.

To quote Dr. Nathan again:

(The ball’s) motion is determined by the forces acting on it. These forces are the downward force of gravity that we are all familiar with as well as two principal aerodynamic forces: the drag force and the Magnus force. Both the drag and Magnus forces result from small imbalances of the air pressure on different parts of the ball. If the baseball is also spinning, it experiences the Magnus force, which is responsible for the curve or “break” of the baseball. The direction of the force is such that the ball breaks in the direction that the leading edge of the ball is turning.

With no gravity and limited drag force in outer space we have virtually no Magnus Effect, thus taking away the pitcher’s main weapon – spin rate – relative to fooling a batter or inducing a specific type of contact.

Now, I’m sure you’re thinking, “Wait, a knuckleball has no spin and can be very effective when thrown right. What gives!”

Let’s once again reference the indispensable Dr. Nathan. Below are two charts with the trajectory of a knuckleball – one with gravity (the first image) and one without gravity (the second image).

KnuckleBall Trajectory
Knuckleball Trajectory with gravity.
KnuckleBall Trajectory2
Knuckleball trajectory without gravity.

With that in mind, let’s turn to an article on Dr. Nathan’s website entitled “Anatomy Of A Nasty Pitch: Why Is Knuckleball Movement So Erratic”  

“Had the ball been thrown with, say, only 1 revolution, the movement associated with the second break (to Dickey’s left) would have occurred too late in the trajectory to have much of an effect. Note that the force also affects the vertical motion, although that is much harder to discern because that motion is largely determined by gravity.”

We can conclude that the effectiveness of the knuckleball is minimized severely due to the non-existence of gravity which, as we just learned, plays a large role in the flight of a knuckleball.

Now that we have discussed pitch spin, how about pitch speed?

According to Dr. Stephen Levy, Assistant Professor of Physics at Binghamton University, calculating the size of the drag force – which has a large effect on pitch speed – can be a little complicated. Dr. Levy notes that it depends on the amount of air there is in a given volume, and on the size, shape and speed of the baseball. For a fastball, the size of the drag force depends on the value of the velocity times itself.

With that, Dr. Levy calculates that a 90 mph fastball will be moving about 10 mph slower when it crosses home plate on Earth. Furthermore, he explains that gravity will also be accelerating the ball vertically down as it travels to home plate and will cause its downward velocity to increase from 0 to about 10 mph.

According to Dr. Levy, this downward velocity is not very important compared to the speed that the ball is moving horizontally. The effect of gravity does mean that the ball will drop about three feet from the height that the pitcher releases it by the time it crosses home plate.

In terms of outer space, we have deduced that there is no drag force to reduce the horizontal speed of a pitched baseball. So a 90 mph fastball will still be moving 90 mph when it reaches the batter, which – in effect – would be the only ‘advantage’ a pitcher would have.

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To summarize…

  • According to Dr. Nathan, there is a difference between total spin and useful spin
  • With no gravity and limited to no drag force in outer space there is virtually no Magnus Effect, thus taking away the pitcher’s main weapon – spin rate – relative to fooling a batter or inducing a specific type of contact.
  • Without gravity, a knuckleball’s main weapon – little spin – is not nearly as effective as it is with gravity
  • According to Dr. Levy, a ball pitched 90 mph from the pitcher’s mound will be traveling about 10 mph slower when it crosses home plate, while a ball pitched in outer space will still be moving at 90 mph when it reaches the batter – therefore giving the pitcher a slight countermeasure to the disadvantages he may face.

Conclusion:

Because of the lack of spin on a ball in outer space, MLB batters would have a distinct advantage over MLB pitchers, even with the lack of drag force.

Footnotes:

¹ While the last part may not be 100% true, Dr. Furukawa did show everyone that you can be a pitcher, batter and fielder all at once if you are playing in space.

#DKBaseball