The National Football League is not the sort of place you would expect to find a discussion about General Relativity; however, "upon further review," it can be quite interesting to see the similarities between Einstein's seminal theory of gravitation and the great game of football.
Football fans everywhere know that the force of gravity between the ground and the ball can make the difference between a field goal making it over the crossbar or a long quarterback heave coming up short and being intercepted. So I started thinking about Einstein's General Theory of Relativity and wondering how it impacts play on the gridiron.
Gravity, the force of attraction between any two objects that have mass is one of the four fundamental interactions known to physicists (and probably Bill Belichick, too) The other fundamental forces do not have as great an impact in the gridiron universe.
The Strong and Weak force operate at a sub-nuclear level, so not even John Madden’s telestrator can detect them. The Electromagnetic force is responsible for many mundane everyday things such as ensuring the players cleats grip the turf correctly and that the football will bounce upon hitting the crossbar on a failed PAT attempt.
It was Isaac Newton who first formulated a mathematical theory of gravitation in the 17th century. Newton's was able to quantify the force of gravity however an explanation as to what gravity actually is was still missing.
In 1919, Albert Einstein extended his special theory of relativity to include accelerated motion and thus provided the world with the best way of understanding the vagaries of gravity. (Even if it doesn’t incorporate quantum mechanics, just like the way the Jets gameplan last year didn't incorporate a running game.)
Long before Johnny Unitas threw his first touchdown pass, Einstein had discovered that gravitational forces are a result of the curvature of space and time. Space and time are now fused together forming a four-dimensional space-time. How come it took physicists so long to understand the importance of space-time.
Ask any football fan and he or she will tell you that field management and clock management are both vitally important. Space in the form of a 100-yard long field and time in the form of a 60-minute game clock are not independent.
It’s no good gaining 40 yards on a drive that lasts eight minutes when you need to score. General Relativity from a football perspective seems elementary.
But what about gravity? What makes the ball fall? To understand this idea we have to accept that a large mass such as the Earth (and not Albert Haynesworth) is capable of bending the fabric of space-time.
When the kicker takes the opening kickoff and sends the football skywards it appears to travel along an approximately parabolic path. However from the point of view of someone in an inertial free reference frame, the ball, traveling along a depression in space time caused by the Earth’s mass, moves in a straight line along the path of least action.
Although when sitting in your front room watching Monday Night Football on ESPN, you are not in an inertial free reference frame, and so from your perspective, the ball take it’s everyday flight and rarely travels in a straight line.
Apart from describing the gravitational force, Einstein’s theory of general relativity explains other phenomenon within the physical world (including the NFL). Einstein's equations predict an expanding universe which evolves dynamically in time and space.
In the early part of the 20th, century this prediction did not agree with observational data so Einstein, for the first time in his life ignored his natural instincts and introduced a new retarding factor into the equations called the Cosmological Constant.
This parameter meant that the universe model became static and no longer expanded.
In a similar fashion, Paul Tagliabue could tell from team’s accounts and balance sheets that the financial level of pro football was increasing rapidly and needed to be stopped. So Tag introduced his own “Cosmological Constant”, namely the concept of a salary cap.
However, once Edwin Hubble discovered that we did in fact live in an expanding universe, Einstein removed the constant from his equations, describing it as ‘the biggest blunder’ of his career.
I don't think current NFL commissioner Roger Godell would consider "salary cap" a blunder, but it looks like it will be removed soon if there is no agreement with the Players Union and the league enters a salary cap free year.
Other bizarre consequences predicted by Einstein’s theory of relativity include time travel. The possibility to travel back into the past due to a severe warpage of space-time. Football fans are well used to the concept of time travel.
We experience it every Sunday in the form of "instant replay." The head coach has the right to challenge a certain officiating decision and if the challenge is upheld then the decision is altered.
Thus changing something which happened in the past. Nothing could be simpler. However throwing a red hankie onto the field of play is a little easier than warping the fabric of space and time!
Another ramification of general relativity which should definitely be familiar to NFL fans is the prediction of the existence of ‘black holes’. When a massive star dies it may form a concentration of matter so strong as to curve space/time round upon itself so that nothing, not even light can escape.
Take a trip to the Oakland Coliseum and there is a possibility that you may get sucked into a “black hole” of hostile fans. I think I’d prefer to take my chances escaping unharmed from the cosmological black hole.
Easily the most famous result from relativity is the equivalence of mass and energy ( E=mc2). This is the equation for which Einstein is best remembered. How does this have any impact on the pro football you may ponder?
Well ask any NFL defender and they’ll agree that at 264lbs, Brandon Jacobs is able to convert a lot of mass into energy, even if he is not quite travelling at the speed of light !!!
So there you have it. The beauty of General Relativity should not be confined to the realm of academia. It is a theory which can be enjoyed by all. The NFL is one stage on which the subtle nuances of relativistic behavior are played out week after week (well, with a little imagination that is).
It is probably unlikely that Stephen Hawking will ever become head coach of the Dallas Cowboys or that Wade Phillips will be professor of theoretical physics at Oxford. Unless of course we start to consider..."parallel universes.” Now there’s a thought.