How Far Can You Fall and Still Survive?

IStock
IStock

You’re on a plane. You’re bored. You stare out the window at the clouds. You wonder what would happen if you couldn’t resist the urge to open the emergency exit and plummet to the earth below. Is death certain? Or would you pick yourself up, set a broken bone or two, and proceed directly to a mental institution with a great story?

Let’s first toss out some variables that often bog down this fair—albeit morbid—question. Forget Felix Baumgartner, the man who filmed himself jumping from 128,100 feet. He had a cool pressurized suit and a parachute. And let’s set aside what free-fall experts have coined “wreckage riders,” those who have fallen while trapped inside a portion of broken aircraft. (The larger surface area increases air drag, slowing their descent. Still likely fatal, but the odds improve somewhat: Serbian flight attendant Vesna Vulovic fell 33,000 feet this way in 1972 and lived to tell her tale—once she woke up from her coma.)

Let’s instead restrict the question to a single individual without any equipment, encasement, or premeditation. You’ve ripped the exit door open like a lunatic. You begin to fall. What now?

We know for certain a person can survive a fall of at least 20,000 feet. That’s how far up World War II pilot Alan Magee was when he had to abandon his plane without a parachute. He crashed through a glass roof that likely helped spread out the impact. According to James Kakalios, Ph.D., a professor at the School of Physics and Astronomy at the University of Minnesota, how and where you land is one of the major factors in whether you get up from the ground or go 6 feet further into it.

“If you can make the time [landing] longer, the force needed to stop you is smaller,” he says. “Think of punching a wall or a mattress. The wall is rigid and the time of interaction is short so the force is large. People who have survived falls, they’ve managed to increase that time, even if it’s in milliseconds. From one millisecond to three, that’s three times longer, three times less force needed for the same change in momentum.” Magee’s glass landing likely reduced the impact; other survivors have plummeted into snow, trees, or something that can better absorb your landing than, say, concrete.

The other major factor? Slowing your descent. Increasing surface area means more energy is required to push air out of your way, slowing you down. The “flying squirrel” position, body splayed out, is preferred over falling feet or head first. “Increasing that drag is the biggest factor in keeping you alive,” Kakalios says. A parachute’s large surface area is best, obviously. Without one, fall belly down or try tumbling. “Drop a pen off the Empire State Building straight down and it might kill someone. But if it drops sideways, spinning end over end, it probably wouldn’t.”

You’re increasing air drag. You’re trying to land in snow or something absorbent. If you’ve passed out from lack of oxygen at high altitudes, you’ve woken up in time to orient yourself. Magee traveled 20,000 feet—nearly four miles—so you know survival is possible from there. What about going higher?

Kakalios stops short of offering a prediction, citing the numerous variables involved. (“Even how much clothing is fluttering behind you can affect surface profile,” he says.) So we pestered someone else: Paul Doherty, Ph.D., a physicist and Co-Director of the Exploratorium, a learning center in San Francisco, California.  

“As you get higher up, the air gets thinner and thinner,” he says. “You can spin so fast the blood can rush into your head and kill you. Or the friction with the elevation will burn you up. That’s why space shuttles have heat insulating tiles.”

Once terminal velocity (maximum acceleration, usually 120 miles per hour for average-sized humans) is reached, Doherty says, it doesn’t really matter whether you throw another 5000 or 10,000 feet on top of Magee’s 20,000: You’re not going to fall any faster. But start too high up and the lower atmospheric pressure means your blood might start to boil. That’s believed to happen around 63,000 feet, though data is obviously limited, and Doherty thinks it might be as high as 100,000. (NASA mandates pressure suits starting at 50,000 feet just to be on the safe side.)

So falling just under 63,000 feet is survivable, in theory? “Let’s say 60,000, Doherty says. Up to 100,000 if you wake up after passing out. And if your blood doesn’t boil. And if you can impact something.”

Stay on the plane.

What Is the Kitchen Like on the International Space Station?

iStock/Elen11
iStock/Elen11

Clayton C. Anderson:

The International Space Station (ISS) does not really have a "kitchen" as many of us here on Earth might relate to. But, there is an area called the "galley" which serves the purpose of allowing for food preparation and consumption. I believe the term "galley" comes from the military, and it was used specifically in the space shuttle program. I guess it carried over to the ISS.

The Russian segment had the ONLY galley when I flew in 2007. There was a table for three, and the galley consisted of a water system—allowing us to hydrate our food packages (as needed) with warm (tepid) or hot (extremely) water—and a food warmer. The food warmer designed by the Russians was strictly used for their cans of food (about the size of a can of cat food in America). The U.S. developed a second food warmer (shaped like a briefcase) that we could use to heat the more "flexibly packaged" foodstuffs (packets) sent from America.

Later in the ISS lifetime, a second galley area was provided in the U.S. segment. It is positioned in Node 1 (Unity) and a table is also available there for the astronauts' dining pleasures. Apparently, it was added because of the increasing crew size experienced these days (6), to have more options. During my brief visit to ISS in 2010 (12 days or so) as a Discovery crewmember, I found the mealtimes to be much more segregated than when I spent five months on board. The Russians ate in the Russian segment. The shuttle astronauts ate in the shuttle. The U.S. ISS astronauts ate in Node 1, but often at totally different times. While we did have a combined dinner in Node 1 during STS-131 (with the Expedition 23 crew), this is one of the perceived negatives of the "multiple-galley" scenario. My long duration stint on ISS was highlighted by the fact that Fyodor Yurchikhin, Oleg Kotov, and I had every single meal together. The fellowship we—or at least I—experienced during those meals is something I will never, ever forget. We laughed, we argued, we celebrated, we mourned …, all around our zero-gravity "dinner table." Awesome stuff!

This post originally appeared on Quora. Click here to view.

Clayton "Astro Clay" Anderson is an astronaut, motivational speaker, author, and STEAM education advocate.

His award-winning book The Ordinary Spaceman, Astronaut Edition Fisher Space Pen, and new children's books A is for Astronaut; Blasting Through the Alphabet and It's a Question of Space: An Ordinary Astronaut's Answers to Sometimes Extraordinary Questions are available at www.AstroClay.com. For speaking events www.AstronautClayAnderson.com. Follow @Astro_Clay #WeBelieveInAstronauts

What Do the Numbers and Letters on a Boarding Pass Mean?

iStock.com/Laurence Dutton
iStock.com/Laurence Dutton

Picture this: You're about to embark on a vacation or business trip, and you have to fly to reach your destination. You get to the airport, make it through the security checkpoint, and breathe a sigh of relief. What do you do next? After putting your shoes back on, you'll probably look at your boarding pass to double-check your gate number and boarding time. You might scan the information screen for your flight number to see if your plane will arrive on schedule, and at some point before boarding, you'll also probably check your zone and seat numbers.

Aside from these key nuggets of information, the other letters and numbers on your boarding pass might seem like gobbledygook. If you find this layout confusing, you're not the only one. Designer and creative director Tyler Thompson once commented that it was almost as if "someone put on a blindfold, drank a fifth of whiskey, spun around 100 times, got kicked in the face by a mule … and then just started puking numbers and letters onto the boarding pass at random."

Of course, these seemingly secret codes aren't exactly secret, and they aren't random either. So let's break it down, starting with the six-character code you'll see somewhere on your boarding pass. This is your Passenger Name Reference (or PNR for short). On some boarding passes—like the one shown below—it may be referred to as a record locator or reservation code.

A boarding pass
Piergiuliano Chesi, Wikimedia Commons // Public domain

These alphanumeric codes are randomly generated, but they're also unique to your personal travel itinerary. They give airlines access to key information about your contact information and reservation—even your meal preferences. This is why it's ill-advised to post a photo of your boarding pass to social media while waiting at your airport gate. A hacker could theoretically use that PNR to access your account, and from there they could claim your frequent flier miles, change your flight details, or cancel your trip altogether.

You might also see a random standalone letter on your boarding pass. This references your booking class. "A" and "F," for instance, are typically used for first-class seats. The letter "Y" generally stands for economy class, while "Q" is an economy ticket purchased at a discounted rate. If you see a "B" you might be in luck—it means you could be eligible for a seat upgrade.

There might be other letters, too. "S/O," which is short for stopover, means you have a layover that lasts longer than four hours in the U.S. or more than 24 hours in another country. Likewise, "STPC" means "stopover paid by carrier," so you'll likely be put up in a hotel free of charge. Score!

One code you probably don’t want to see is "SSSS," which means your chances of getting stopped by TSA agents for a "Secondary Security Screening Selection" are high. For whatever reason, you've been identified as a higher security risk. This could be because you've booked last-minute or international one-way flights, or perhaps you've traveled to a "high-risk country." It could also be completely random.

Still confused? For a visual of what that all these codes look like on a boarding pass, check out this helpful infographic published by Lifehacker.

Have you got a Big Question you'd like us to answer? If so, send it to bigquestions@mentalfloss.com.

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