What if everyone on earth aimed a laser pointer at the moon at the same time? What if you could drain all the water from the oceans? What if all the lightning strikes in the world hit the same place at once? What if there was a book that considered weird, sometimes ridiculous questions, and it was so compelling that you found yourself skimming its pages to find out what would happen if you threw a baseball at light speed? With What If, Randall Munroe has written such a book. In the same style of his extraordinarily popular xkcd webcomic, Munroe applies reason and research to hypothetical conundrums ranging from the philosophical to the scientific (often absurd, but never pseudo) that probably seemed awesome and inscrutable in your elementary school days--but were never sufficiently answered.
Enjoy this exclusive thought-experiment from the author (and it's not even included in the book). What If? Serious Scientific Answers to Absurd Hypothetical Questions will be available in hardcover and Kindle on September 2, 2014.
Q: If you built a very smooth ramp from the highest point on Earth (Mt. Everest) to the lowest (Dead Sea), then stood at the top on a rolling office chair, would you roll down? How fast would you go?
So you got bored in a meeting and decided to take your chair for a ride.
Bring oxygen tanks. And food.
A ramp connecting Mount Everest to the shore of the Dead Sea would have a very gentle slope of only 1/10th of a degree. If you were standing on it, it would seem flat.
The slope would be so gentle that the chair would need precision bearings or a pneumatic air cushion to reduce friction enough to roll—and even then, air drag would limit you to a terminal velocity of about running speed.
You'd also need the ramp to be enclosed. The top of Mount Everest pokes up into the jet stream, a river of hurricane-force wind wrapped around the planet. Unfortunately for you, that wind is going in the wrong direction. Without something to shield you from it, it would blow you back up the ramp.
Ok, let's go!
You depart the peak of Everest, trundling slowly west, and the ground falls away beneath you. You glide out over the peaks and valleys of the Himalayas without coming close to touching another mountain.
After two days, you leave the mountains behind and slide across the Punjab region of India and Pakistan.
You then cross southern Afghanistan and pass into Iran, where you finally sink low enough to breathe without oxygen tanks.
In central Iran, you hit the ground for the first time since you started rolling. Your track intersects a mountainside near the peak of Shahan Kuh. You pass through a convenient tunnel and emerge on the other side.
You cross from Iran into Iraq, sinking lower and lower. Because the air is several times denser here than at your starting point, your terminal velocity has dropped from running speed to jogging speed.
A little over two weeks after you started rolling, your ramp sinks low enough to touch the desert. In western Iraq, you fall beneath ground level and enter another tunnel. You cross from Iraq into Jordan over 600 meters below the border.
You roll through the darkness for four days, passing completely under Jordan, and finally emerge into the light on the shores of the Dead Sea.
After twenty days, you and your faithful chair have reached the end of your journey from Earth's highest land to its lowest. You take a swim; in the dense saline water, you float much higher than normal. Be careful not to get any in your eyes.
And now you should probably get back to that meeting. They'll get mad if you don't return the chair.