Not every science fiction novel involves spaceships and space travel, but many of them do. What's interesting about space travel in science fiction—and by "interesting" I mean "unfair"—is that the actual space travel gets all the glory while one of the key players in that romanticism goes unappreciated.

I'm talking about, of course, the space elevator.

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Simply put, a prerequisite of traveling through space means first getting into space. But nobody ever thinks about that, do they? Oh sure, there are rockets. But rockets expend huge amounts of fuel and are a costly way to carry a limited number of resources. A better method would be something that's more permanent like, say, a space elevator.

How It Works

Did you ever go "around the world" with a yo-yo? That's the basic concept behind a space elevator, except the yo-yo is a counterweight and your hand is the Earth. The idea is that the rotation of the Earth serves to propel this counterweight into space, which is exactly what it would do were it not tethered to the planet by a massive cable (the string on your yo-yo). That cable is the elevator shaft that would allow us to rise above the Earth's atmosphere and get into space. From there, we could shuttle our way to a space station's launch pad and get on with our travels. In a sense, the space elevator is like the jetway at an airport. (Those also get no respect, but that's another article.)

To work properly the space elevator cable would need to be attached to the Earth where it would move the fastest: at the planet's equator (or close enough to it that it mathematically won't matter). This is where the Earth's rotation would generate the greatest centrifugal force. Think of centrifugal force as the power with which the aforementioned yo-yo would go flying across the room. The greater that force, the more taut the cable will be.

Topsy-Turvy

Here's the cool thing: as a person travels up the cable, the gravitational effect of the centrifugal force begins to equal Earth's gravitational force. Before this turns into a boring science lecture, what this means is that at some point in the middle of the cable, a person traveling up the space elevator would begin to experience weightlessness, long before our astronauts ever did. Cool, huh?

Wait, it gets even better. As the passenger continues to travel along the cable, the effect of the centrifugal force overcomes Earth's gravity. The feeling of having weight will return, but up becomes down and vice versa. Since the Earth's rotation is throwing you away from the planet, the Earth would feel like it was "above" you. "Below" you would be outer space, or at least the space elevator's counterweight.

Space Elevators in Science Fiction

Space elevators are a cool concept, and although they are often used in science fiction they are not central to the plot. Yep, once again, space elevators get the short end of the publicity stick.

In honor of our vertical literary device friends, let's note some novels in which space elevators make a stalwart appearance, while we applaud them:

• Feersum Endjinn by Iain M. Banks
• Across the Sea of Suns by Gregory Benford
• Mercury by Ben Bova
• The Fountains of Paradise by Arthur C. Clarke
• Sunstorm by Arthur C. Clarke and Stephen Baxter
• Jumping Off the Planet by David Gerrold
• The End of the Empire by Alexis A. Gilliland
• There is No Darkness by Jack C. Haldeman II
• Friday by Robert A. Heinlein
• Sun's End by Richard Lupoff
• Deepsix by Jack McDevitt
• Singularity's Ring by Paul Melko
• Rainbow Mars by Larry Niven
• Starclimber by Kenneth Oppel
• Chasm City by Alastair Reynolds
• Red Mars by Kim Stanley Robinson
• Foreigner by Robert J. Sawyer
• The Web Between the Worlds by Charles Sheffield
• Coyote Frontier by Allen Steele
• Echoes of Earth by Sean Williams and Shane Dix

John DeNardo is the editor of SF Signal, a group science-fiction and fantasy blog featuring news, reviews and interviews.