xkcd: What If?

[bystander]

Rising Steadily

• If you suddenly began rising steadily at one foot per second, how exactly would you die?
  Would you freeze or suffocate first? Or something else? — Rebecca B.

[neufer]

Rising Steadily

As you approach the Death Zone, your blood oxygen content would plummet. Your veins are supposed to bring low-oxygen blood back to your lungs to be refilled with oxygen. But in the Death Zone, there's so little oxygen in the air that your veins lose oxygen to the air instead of gaining it. The result would be a rapid loss of consciousness and death.

This would happen around the seven hour mark; the chances are very slim that you would make it to eight.

[b][color=#0000FF]Henry Tracey Coxwell[/color][/b]

---

How about death around 11 hours = 39,600 ft.
(Temperature ~ -57 C : Pressure ~ 0.19 atmospheres.)

<<Henry Tracey Coxwell (2 March 1819, Wouldham, Kent - 5 January 1900, Lewes, Sussex, England), was an English aeronaut. He was the son of a naval officer, educated for the army, but became a dentist. From a boy he had been greatly interested in ballooning, then in its infancy, but his own first ascent was not made until 1844. In 1848 he became a professional aeronaut, making numerous public ascents in the chief continental cities. Returning to London, he gave exhibitions from the Cremorne Gardens and subsequently from the Surrey Gardens. By 1861 he had made over 400 ascents. In 1862 in company with Dr James Glaisher, he attained the greatest height on record, about 11,887 m (39,000 ft). His companion became insensible, and he himself, unable to use his frostbitten hands, opened the gas-valve with his teeth, and made an extremely rapid but safe descent. The result of this and other aerial voyages by Coxwell and Glaisher was the making of some important contributions to the science of meteorology. Coxwell was most pertinacious in urging the practical utility of employing balloons in time of war. He says: I had hammered away in The Times for little less than a decade before there was a real military trial of ballooning for military purposes at Aldershot.

Coxwell had a balloon factory in Richmond Road Seaford, Sussex and has a memorial at St Peter's Church, East Blatchington, Seaford.>>

[bystander]

Twitter Timeline Height

• If our Twitter timelines (tweets by the people we follow) actually extended
  off the screen in both directions, how tall would they be? — Anonymous

[geckzilla]

I liked the earlier ones that involved lots of explosions. Boo Twitter.

[bystander]

500 MPH

• If winds reached 500 mph, would it pick up a human? — Grey Flynn, age 7, Stoneham, MA

[bystander]

Expanding Earth

• How long would it take for people to notice their weight gain if the mean radius of the world expanded
  by 1 cm every second? (Assuming the average composition of rock were maintained.) — Dennis O'Donnell

[BMAONE23]

Expanding Earth

• How long would it take for people to notice their weight gain if the mean radius of the world expanded
  by 1 cm every second? (Assuming the average composition of rock were maintained.) — Dennis O'Donnell

iI always thought the earth was expanding

Click to play embedded YouTube video.

[rstevenson]

[bystander]

The Earth is not, currently, expanding.

People have long suggested that it might be. Before the continential drift hypothesis was confirmed in the 1960s, people had noticed that the continents fit together. Various ideas were put forward to explain this, including the idea that the ocean basins were rifts that opened in the surface of a previously-smooth Earth as it expanded. This theory was never very widespread, although it still periodically makes the rounds on YouTube.

[neufer]

The oceans are, however, currently expanding.

[Ann]

The oceans are, however, currently expanding.

Really? I remember reading Rare Earth by Peter Ward and Donald Brownlee, and they claimed that the early Earth was almost totally covered in oceans. Only little archipelagos broke the watery surface.

Ann

[Nitpicker]

The "average" level of the sea has gone up and down since its formation, over millions of years. From current, more accurate measurements from the last century or so, it appears to be on a rising trend. This is partly due to the (relatively slight) expansion of the steadily warming ocean layers near the surface, as well as glacial ice melt running off land into the sea. No doubt due to a few other factors too.

[bystander]

Little Planet

• If an asteroid was very small but supermassive, could you really live on it like the Little Prince? — Samantha Harper

[bystander]

Facebook of the Dead

• When, if ever, will Facebook contain more profiles of dead people than of living ones? — Emily Dunham

[bystander]

The Constant Groundskeeper

• How big of a lawn would you have to have so that when you finished mowing
  you'd need to start over because the grass has grown? — Nick Nelson

[Nitpicker]

The Constant Groundskeeper

• How big of a lawn would you have to have so that when you finished mowing
  you'd need to start over because the grass has grown? — Nick Nelson

Quite relevant. There could conceivably be a severely reduced population of adult male cougars in Iowa:
http://upload.wikimedia.org/wikipedia/c ... p_2010.png

[Ann]

Guess who's coming to dinner? I mean, guess who's here in my hometown right now? Yes, Randall Munroe himself!

http://www.sydsvenskan.se/webb-tv/webb- ... -pa-natet/

Ann

[bystander]

Stirring Tea

• I was absentmindedly stirring a cup of hot tea, when I got to thinking, "aren't I actually
  adding kinetic energy into this cup?" I know that stirring does help to cool down the tea,
  but what if I were to stir it faster? Would I be able to boil a cup of water by stirring? — Will Evans

[bystander]

Loneliest Human

• What is the furthest one human being has ever been from every
  other living person? Were they lonely? — Bryan J. McCarter

[bystander]

Lethal Neutrinos

• How close would you have to be to a supernova to get a lethal dose
  of neutrino radiation? — (Overheard in a physics department)

[bystander]

Soda Planet

• How much of the Earth's currently-existing water has ever been
  turned into a soft drink at some point in its history? — Brian Roelofs

[bystander]

Phone Keypad

• I use one of those old phones where you type with numbers—for example, to type "Y",
  you press 9 three times. Some words have consecutive letters on the same number.
  When they do, you have to pause between letters, making those words annoying to
  type. What English word has the most consecutive letters on the same key? — Stewart Bishop

[bystander]

Reading Every Book

• At what point in human history were there too many (English) books
  to be able to read them all in one lifetime? — Gregory Willmot

[bystander]

Growth Rate

• What height would humans reach if we kept growing through our whole development period
  (i.e. till late teens/early twenties) at the same pace as we do during our first month? — Maria

[bystander]

T-rex Calories

• If a T-rex were released in New York City, how many humans/day would
  it need to consume to get its needed calorie intake? — Tony Schmitz