Technolgy Bites Life

Towers of Babel

May 03, 2002

Play Ball


Cricket is a spectator sport much loved in about eight counties around the world. Baseball is a similar and yet quite different sport much loved in the United States with some following in a few others.  The major similarity between these sports is that both involve a ball thrown by a person at another who attempts to hit it with a wooden bat. While the cricket bat is flat, the baseball bat is round.


For almost as long as bat and ball games have existed, there has been a controversy. Does a ball thrown at a relatively high speed, follow a trajectory that is straight, or does it move around and change direction, often unpredictably? There are oodles of people, notably players who have seen the phenomenon of the curved ball, swear that the ball seems to have a mind of its own and does some pretty amazing changes in course. Many others swear vehemently that such movements are impossible under the laws of physics and unexpected swerving is just an optical illusion.


A ball traveling in a direction cannot change direction unless if there is a force acting upon it. If the ball is thrown in a vacuum then gravity is the only force. Hence the ball drops at the rate prescribed by the Earth’s gravitational attraction. In the presence of air there is a frictional force, which is small, but affects the speed and not direction. A wind would also move the ball but again, it would be constant movement not a sudden turn. So given all the irrefutable laws of Newtonian physics, the ball should traverse straight on a calm day and drop due to gravity.


But the father of Physics, Sir Isaac Newton was supposed to have been aware of balls that curve. Over the years it has been hotly debated, and in 1959 wind tunnel experiments showed balls do indeed curve. Yet, the nay-sayers did not believe it. High-speed photography did not reveal much till now, but finally, yet again, a high tech solution comes to the rescue.


A company called Questec has developed a visual processing system called PitchTrax that follows a fast ball rather accurately. Cameras mounted on the sides of the pitch shoots video of the ball. Then computers process the video and recognizes the ball and its path and maps it to accuracies to a fraction of an inch. Then a three-dimensional graphical image of the ball track is created that can be viewed in slow motion from any direction, or even rotated for a better view. The resulting instant replay is not only spectacular but also quite educational. And yes, PitchTrax clearly shows the curve ball in action.


Why does a ball curve? An explanation was provided by a German named Magnus about 100 years ago. In order for a ball to curve, it has to be spinning. The spin of the ball makes the airspeed on different sides of the ball different. This causes a differential in air pressure and moves the ball sideways. As the ball changes course, the direction of the force due to the differential pressure, changes, making it curve even more. Depending upon the axis of spin, the ball can be made to swerve sideways or drop faster or even rise. This speculation, now proven beyond doubt is called the Magnus Effect. The Magnus Effect plagues not only cricket and baseball, but tennis, golf, soccer and any sport where balls are used.


Apart from bats, balls and Magnus Effects, cricket and baseball are two quite different sports. In baseball, the king of the game is the person who bowls, called the pitcher. A pitcher who starts an innings often pitches continuously for most of the game without relief. He hurls the ball, at speeds over 90mph, towards a frightened-looking batter, aiming to get the ball into an imaginary square behind him (there are no wickets). Balls are thrown full-toss, they do not bounce on the pitch.


The elegance of cricket is not only in the manner it is played but the relative simplicity of the rules. Rules of baseball are to rules of cricket as advanced calculus is to arithmetic. Rules make baseball complex, strategy ridden and statistics prone. One of the earliest uses of computers was to keep real time statistics of major league baseball games.


I have to admit, I am not a sports fan. A man throwing a ball at another, who tries to swipe at it, over and over again, is not quite my idea of fun. Yet, for the sake of learning something, I went to my first live baseball game last week, and I came back humbled.


We headed to the huge new stadium in Phoenix, Bank One Ballpark, also called BOB. The Arizona Diamondbacks were to play the Los Angeles Dodgers. Arizona Diamondbacks is the home team, with a charming name. Phoenix is the home of the Camelback Mountain, a mountain shaped like, no prizes for guessing, the back of a camel. Camelback Mountain adjoins the main business district – a sweeping avenue radiating out from the mountain, called the Camelback Corridor. Baseball is played on a field with an oblong shape, called the “diamond”. And there is more, the Diamondback is an artistically patterned rattlesnake that is native to Arizona. It all somehow fits.


BOB is a majestic tribute to engineering and technology. It is both an indoor and an outdoor stadium. On a nice day the huge roof slides out to reveal the clear blue Arizona sky. When the temperature rises over what would be comfortable, the roof closes and air conditioners blow tons of cooled air to chill the masses. The retractable roof also allows real grass to grow on the field (the sun can shine on the field).


The stadium provides comfortable seating for 50,000 people. Inside its humongous caverns are shops and eateries for those who would like to wander instead of watch. The audio system brings crisp clear voice and music to every seat with no echo, no booming, and no muffling. The huge television screens and scoreboards provide visuals, graphics, advertising, information and many other gimmicks. And of course, fiber optics, wireless and other high-tech gizmos connect cameras, controllers, commentators, referees, coaches and players into one huge seamless network of communications and data flow.


The most impressive impact of a game is the harmonious marriage of technology, sports and choreography. A Diamondbacks game is far from a rare event; there are about 12 to 14 per month, every month. Phoenix is not a very large city; about 3 million people living live here. Convincing 50,000 people to show up (and pay) for 14 games a month, from this limited audience needs far more than just the love for the game.


That is where the choreography, showmanship, entertainment and technology come to the rescue. First there is music. Before every throw of the ball, as the batter takes position, rising in crescendo is music chosen by the batter. The music stops, not abruptly, but in synchrony with the action, just about as the ball is thrown. The coordination creates and effect that is quite interesting (and yes, the precision is beyond human control).


The choreography is also used to pump up the crowd. When its time for the home team to score, or at some crucial juncture of the game, there is no notion of fairness, no notion of cricket. All the high-tech jazz is thrown at the audience in phases of music, visuals and subtle text messages to evoke tumultuous response at remarkably well timed junctures (yes, it does really distract the opposite team).


Of course, there is Doppler radar. Somewhere on the field are radar guns that measure the speed of every ball thrown. This shows up on the scoreboard, and consistently it is in the 90 to 97 miles per hour range (sometimes it exceeds 100mph, but that is rare.) The pitcher (bowler) keeps this up with uncanny accuracy and complete control of the Magnus effect, and the balls whizzes exactly where he wants to. Any ball that does not go into the strike area was purposely not meant to, there is no error in pitching. No wonder, the ace pitchers command salaries in the $10 million per year range.


Technology aside, the precision, the professionalism and the sheer skill of the players are simply amazing. Never is a ball that could be caught is not caught. A ball thrown from a fielder for a “run-out” whizzes in, at astounding speed to the right spot every time. Any mistakes in fielding is called an “error” and is kept track of. We had 1 error that day, many games have none.


While the game is in progress, there is a lot to do. Tucked away in the various levels of the stadium are restaurants, bars, shops, places to hang out while a plethora of TV monitors keep you in touch with the action.  Walking around BOB I was impressed at the attention to detail, and the elegance of the design.


I had planned to spend about two hours at the game, but the aura kept me there. Four hours later, the game ended, and 49,777 (yes, everyone was counted) people trooped out. There was no bottleneck and no massive crowding. A smooth flow of people gushed out steaming down the escalators, into the scattered parking lots. Within 15 minutes, the cars were on the roads and the traffic was directed away to the various destinations (there is hardly any public transport). It is not just a game, and not just a ballpark; its yet another example of what focused thought and hard work can produce.


Partha Dasgupta is on the faculty of the Computer Science and Engineering Department at Arizona State University in Tempe. His specializations are in the areas of Operating Systems, Cryptography and Networking. His homepage is at