What If?: Serious Scientific Answers to Absurd Hypothetical Questions

Question: “What would happen if you tried to hit a baseball pitched at 90 percent the speed of light?” (7).

If it were possible, such a pitch would travel at 600 million miles an hour. Air molecules in the path would either pass through the ball entirely or fuse with the atoms on the ball’s surface, releasing atomic energy. When the ball reaches home plate, it’s an expanding fireball of ionized atoms that incinerates the ballpark and everything for a mile around it.

By baseball rules, though, the batter would be considered hit by the pitch and entitled to walk to first base.

Question: “What if I took a swim in a typical spent nuclear fuel pool?” (10).

Spent fuel rods from a nuclear power plant are highly radioactive; they’re stored for decades in pools of water, which are very good at capturing radiation. Divers routinely service these pools. If you swam down to the rods and touched them, that would be lethal, but every seven centimeters of water cuts the radiation level in half, so if you swam near the surface, you’d be safer than when you got out.

Question: “Would it be possible to get your teeth to such a cold temperature that they would shatter upon drinking a hot cup of coffee?” (14). The author thanks the submitter for giving him a new “recurring nightmare.”

Question: “How many houses are burned down in the United States every year? What would be the easiest way to increase that number by a significant amount (say, at least 15%)?” (14). The author calls the police.

Question: “What would it be like if you traveled back in time, starting in Times Square, New York, 1000 years? 10,000 years? 100,000 years? […] What about forward in time 1,000,000 years?” (15).

A thousand years ago, Manhattan would have contained old-growth forests with chestnut trees and large mammals, including wolves and mountain lions. During the Ice Age, 22,000 years ago, glaciers covered Manhattan; 100,000 years ago, a warming period would have made the area look similar to its wildlands today. That far back, Staten Island, Long Island, and similar coastal features wouldn’t have existed, as they were berms bulldozed by more recent glaciers.

A billion years ago, when the continents clustered together in a super-continent called Rodinia, the New York area was a set of islands off the coast of southern Africa. No land plants or animals existed; all life was in the sea and single-celled.

A million years hence, humanity may live out among the stars, be entirely extinct, or be vastly different. In a billion years, the sun will have heated up, and the oceans will have boiled away; a few billion years later, the sun will expand, incinerating the Earth and blasting its materials out into distant space.

Question: “What if everyone actually had only one soul mate, a random person somewhere in the world?” (23).

Of 100 billion humans who have lived, 93% are dead; thus, if each person has only one soul mate, the odds are 90% that such a person is already deceased. If we include all possible future humans, the odds of meeting the soul mate get even worse, about one in 10,000 lifetimes.

Question: “If every person on Earth aimed a laser pointer at the Moon simultaneously, would it change color?” (27).

If everyone in the Eastern Hemisphere—home of three-fourths of all humans—pointed 5-milliwatt lasers at a half-moon, the lasers would travel first through the atmosphere, spread out a bit, and land on the Moon so diffused that the beam would spread out over about 10% of the surface. On the bright side of the half-moon, the sun shines two megawatts of light per person, completely swamping the tiny lasers.

Fifty trillion-megawatt laser weapons, though, would cause the Moon to shine as bright as the sun at noon; two minutes’ worth of this event would use up the Earth’s entire supply of fossil fuels.

Question: “What would happen if you made a periodic table out of cube-shaped bricks, where each brick was made of the corresponding element?” (35).

Some collectors already try to do this. Thirty elements are available at retail stores; some can be scavenged from, for example, smoke detectors; a few are dangerously radioactive and/or illegal to own; the rest are too unstable to hold onto for more than a few seconds.

If it were possible to collect such cubes, the first rows would set fire to the lower rows of heavier elements, releasing poisons and explosions; the bottom rows, with the heaviest elements, would detonate like an atom bomb. Thus, it’s not advised even to try to collect all the elements into one set of cubes.

Question: “What would happen if everyone on Earth stood as close to each other as they could and jumped, everyone landing on the ground at the same instant?” (43).

If everyone in the world were in one place, like Rhode Island, and they all jumped and landed, the energy released would barely affect the Earth, but the noise of all the feet striking the ground at the same time would create a very loud roar for several seconds.

Getting all those people out of Rhode Island would be extremely difficult. Local airports would take decades to transport them; railroads would similarly be swamped. Food supplies would be exhausted; soon, billions would die. The Earth, however, would spin on as before, unaffected by the jump.

Question: “What would happen if you were to gather a mole (unit of measurement) of moles (the small furry critter) in one place?” (47).

A mole is a small, furry animal. It’s also a quantity, Avogadro’s number, 6.02x10^23, an enormous figure used for counting molecules. A mole of eastern moles, weighing 75 grams each and mostly water, when collected into a sphere, would make a ball slightly larger than the Moon. Such a ball of meat would take thousands of years to cool and, eventually, freeze.