I teleported home one night
With Ron and Sid and Meg.
Ron stole Meggie’s heart away
And I got Sidney’s leg.
—Douglas Adams, The Restaurant at the End of the Universe
This humorous take on teleportation has always appealed to me because it reminds me that every technology has glitches, and imagined future technology might have spectacular failures.
Science fiction writers have used teleportation in many books, TV shows, and movies, and have paid more or less attention to the problems inherent in the idea. The new Doug Liman film, Jumper, makes use of teleportation to produce some cool effects and fun visuals, but doesn’t worry much about the details. In the Jumper universe a few people have the natural ability from age five on to teleport themselves to any location they already know. With practice, these “jumpers” can bring objects or people along with them when they jump. Another group, known as “paladins,” hunts the jumpers and tries to kill them for largely unexplained reasons. The film follows David Rice (Hayden Christensen) as he learns of his ability and of the ongoing war between jumpers and paladins.
In this column, I’m not going to worry about the possibility of teleportation—others have addressed that issue more fully than I can here (see, for instance, this New York Times article). Instead, I’ll look at how consistently the film applies everyday physics to the jumpers and their movements around the globe.
Many times in the movie we see that objects and people maintain their momentum in the process of being teleported. So when Griffin (Jamie Bell) brings a London bus back to the Egyptian desert in the middle of the climactic battle, it arrives moving at the same speed as when it left London. I like this principle visually. It means David can start to hop into a convertible from the driver’s side and land gracefully in the passenger seat by teleporting across the car. It does lead to some problems with consistency, though. If jumpers bring their momentum with them, they ought to bring it all along.
For my concern to make sense, it is essential to remember that we are on a rotating globe, which means we are traveling east at a fairly high speed. We get back to where we started (ignoring our motion around the Sun) by moving in a circle every 24 hours. At the equator, that circle has a circumference of about 40,000 km (25,000 miles). Using speed = distance/time, we can figure out that everything on the equator is heading east at about 1700 km/hr, or over 1000 mph. The farther you are from the equator, the smaller the circle you move in every day, and the slower your speed.
As I described above, in the Jumper universe people maintain their momentum when they jump, but the writers have ignored that moving north or south on the Earth leads to a mismatch in eastbound speed. When David jumps from New York to London, he ends up about 10 degrees farther north, so he’d be moving much too fast for London when he got there. He’d smash into the west side of the nearest building. There is even more of a mismatch when he leaves London a few hours later to surf near Fiji, a transition from a latitude of 50°N to 20°S. A bit of trigonometry will show that Fiji is moving about 500 km/hr faster than London, and that’s a problem even a top-notch surfer can’t overcome.
The writers do better with the jumpers’ movements east and west around the globe. Anyone who has made an international call to Europe or Asia from North America remembers that the time difference can lead to lost sleep or missed business hours. Moving from New York to London is a shift of five time zones, and in David’s early trips, the changes in daylight seem consistent with reality. The first jump we see from New York to London takes David from Manhattan daylight to darkness at 8:30 PM on Big Ben. After some time in London, the surf trip to Fiji, and lunch on top of the Sphinx, he returns to New York after dark. This attention to physical reality falls apart in the final battle, however. As David and Griffin quickly pass through locations in the Egyptian desert, Rome, the Pyramids at Giza, Dubai, and beyond, the continuity of time zones is lost. Rome and Giza are only one hour apart, but that jump takes them from complete darkness to midday sun.
Jumper provides an excellent opportunity for middle school science teachers to talk about the Earth’s rotation in very practical terms: how time zones work, and where daylight and darkness exist at a given moment. High school physics teachers might set their students the task of finding the tangential speed of the Earth at various points on the globe to then calculate David’s speed mismatch in a few specific jumps.
Editor's note: This is the first in an ongoing series of movie reviews whose aim is to examine how scientific concepts are used, misused, or simply ignored on the silver screen.
Jacob Clark Blickenstaff is Assistant Professor of Physics and Assistant Director of the Center for Science
and Mathematics Education at the University of Southern Mississippi. He can be reached at email@example.com.
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