What can you do in 26 seconds?
For starters, it’s enough time to get all the way through the original Super Mario World 1-1, assuming you have perfect timing and take the shortcut through the pipe.
It’s also long enough to miss a phone call. Sprint’s ring cycle—the time the phone rings before going to voicemail—is 23 seconds.1
If someone called your phone, and it started ringing the moment you jumped, it would go to voicemail three seconds before you reached the bottom.
On the other hand, if you jumped off Ireland’s 210-meter Cliffs of Moher, you would be able to fall for only about eight seconds—or a little more, if the updrafts were strong. That’s not very long, but according to River Tam, given adequate vacuuming systems it might be enough time to drain all the blood from your body.
So far, we’ve assumed you’re falling vertically. But you don’t have to.
Even without any special equipment, a skilled skydiver—once he or she gets up to full speed—can glide at almost a 45-degree angle. By gliding away from the base of the cliff, you could conceivably extend your fall substantially.
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA ::gasp:: AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
It’s hard to say exactly how far; in addition to the local terrain, it depends heavily on your choice of clothes. As a comment on a BASE jumping records wiki puts it,
The record for longest [fall time] without a wingsuit is hard to find since the line between jeans and wingsuits has blurred since the introduction of more advanced . . . apparel.
Which brings us to wingsuits—the halfway point between parachute pants and parachutes.
Wingsuits let you fall much more slowly. One wingsuit operator posted tracking data from a series of jumps. It shows that in a glide, a wingsuit can lose altitude as slowly as 18 meters per second—a huge improvement over 55.
Even ignoring horizontal travel, that would stretch out our fall to over a minute. That’s long enough for a chess game. It’s also long enough to sing the first verse of—appropriately enough—REM’s “It’s the End of the World as We Know It,” followed by—less appropriately—the entire breakdown from the end of the Spice Girls’ “Wannabe.”
When we include the higher cliffs opened up by horizontal glides, the times get even longer.
There are a lot of mountains that could probably support very long wingsuit flights. For example, Nanga Parbat, a mountain in Pakistan, has a drop of more than 3 kilometers at a fairly steep angle. (Surprisingly, a wingsuit still works fine in such thin air, though the jumper would need oxygen, and it would glide a little faster than normal.)
So far, the record for longest wingsuit BASE jump is held by Dean Potter, who jumped from the Eiger—a mountain in Switzerland—and flew for three minutes and twenty seconds.
What could you do with three minutes and twenty seconds?
Suppose we recruit Joey Chestnut and Takeru Kobayashi, the world’s top competitive eaters.
If we can find a way for them to operate wingsuits while eating at full speed, and they jumped from the Eiger, they could—in theory—finish as many as 45 hot dogs between them before reaching the ground . . .
. . . which would, if nothing else, earn them what just might be the strangest world record in history.
1For those keeping score, that means Wagner’s is 2,350 times longer.
weird (and worrying) questions from the what if? INBOX, #9
Q. Could you survive a tidal wave by submerging yourself in an in-ground pool?
—Chris Muska
Q. If you are in free fall and your parachute fails, but you have a Slinky with extremely convenient mass, tension, etc., would it be possible to save yourself by throwing the Slinky upward while holding on to one end of it?
—Varadarajan Srinivasan
Sparta
Q. In the movie 300 they shoot arrows up into the sky and they seemingly blot out the sun. Is this possible, and how many arrows would it take?
—Anna Newell
A. It’s pretty hard to make this work.
Attempt 1
Longbow archers can fire eight to ten arrows per minute. In physics terms, a longbow archer is an arrow generator with a frequency of 150 millihertz.
Each arrow spends only a few seconds in the air. If an arrow’s average time over the battlefield is three seconds, then about 50 percent of all archers have arrows in the air at any given time.
Each arrow intercepts about 40 cm2 of sunlight. Since archers have arrows in the air only half the time, each blocks an average of 20 cm2 of sunlight.
If the archers are packed in rows, with two archers per meter and a row every meter and a half, and the archer battery is 20 rows (30 meters) deep, then for every meter of width . . .
. . . there will be 18 arrows in the air.
18 arrows will block only about 0.1 percent of the Sun from the firing range. We need to improve on this.
Attempt 2
First, we can pack the archers more tightly. If they stand with the density of a mosh pit crowd,1 we can triple the number of archers per square foot. Sure, it will make firing awkward, but I’m sure they can figure it out.
We can expand the depth of the firing column to 60 meters. That gives us a density of 130 archers per meter.
How fast can they fire?
In the extended edition of the 2001 film Lord of the Rings: The Fellowship of the Ring, there’s a scene where a group of orcs2 charge at Legolas, and Legolas draws and fires arrows in rapid succession, felling the attackers with one shot each before they reach him.
The actor playing Legolas, Orlando Bloom, couldn’t really fire arrows that quickly. He was actually dry-firing an empty bow; the arrows were added using CGI. Since this fire rate appeared, to the audience, to be impressively fast but not physically implausible, it provides a convenient upper limit for our calculations.
Let’s assume we can train our archers to replicate Legolas’s fire rate of seven arrows in eight seconds.
In that case, our column of archers (firing an impossible 339 arrows per meter) will still block out only 1.56 percent of the sunlight passing through them.
Attempt 3
Let’s dispense with the bows entirely and give our archers arrow-firing Gatling bows. If they can fire 70 arrows per second, that adds up to 110 square meters of arrows per 100 square meters of battlefield! Perfect.
But there’s a problem. Even though the arrows have a total cross-sectional area of 100 meters, some of them shadow each other.
The formula for the fraction of ground coverage by a large number of arrows, some of which overlap each other, is this:
With 110 square meters of arrows, you’ll cover only two-thirds of the battlefield. Since our eyes judge brightness on a logarithmic scale, reducing the Sun’s brightness to a third of its normal value will be seen as a slight dimming; certainly not “blotting it out.”
With an even more unrealistic fire rate, we could make it work. If the guns release 300 arrows per second, they would block out 99 percent of the sunlight reaching the battlefield.
But there’s an easier way.
Attempt 4
We’ve been making the implicit assumption that the Sun is directly overhead. That’s certainly what the movie shows. But perhaps the famous boast was based on a plan to attack at dawn.
If the Sun were low on the eastern horizon, and the archers were firing north, then the light could have to pass through the entire column of arrows, potentially multiplying the shadow effect a thousandfold.
Of course, the arrows wouldn’t be aimed anywhere near the enemy soldiers. But, to be fair, all they said was that their arrows would blot out the Sun. They never said anything about hitting anyone.
> And who knows; maybe, against the right enemy, that’s all they need.
1Rule of thumb: One person per square meter is a light crowd, four people per square meter is a mosh pit.
2Strictly speaking, they were Uruk-Hai, not typical orcs. The precise nature and origin of the Uruk-Hai is a little tricky. Tolkien suggested that they were created by cross-breeding humans with orcs. However, in an earlier draft, published in The Book of Lost Tales, he instead suggests the Uruks had been born from the “subterranean heats and slimes of the Earth.” Director Peter Jackson, when deciding what to show on-screen in his film adaptation, wisely went with the latter version.
Drain the Oceans
Q. How quickly would the oceans drain if a circular portal 10 meters in radius leading into space were created at the bottom of Challenger Deep, the deepest spot in the ocean? How would the Earth change as the water was being drained?
—Ted M
A. I want to get one thing out of the way first:
According to my rough calculations, if an aircraft carrier sank and got stuck against the drain, the pressure would easily be enough to fold it up and suck it through. Cooool.
Just how far away is this portal? If we put it near the Earth, the ocean would just fall back down into the atmosphere. As it fell, it would heat up and turn to steam, which would condense and fall right back into the ocean as rain. The energy input into the atmosphere alone would also wreak all kinds of havoc with our climate, as would the huge clouds of high-altitude steam.
So let’s put the ocean-dumping portal far away—say, on Mars. (In fact, I vote we put it directly above the Curiosity rover; that way, it will finally have incontrovertible evidence of liquid water on Mars’s surface.)
What happens to the Earth?
Not much. It would actually take hundreds of thousands of years for the ocean to drain.
Even though the opening is wider than a basketball court, and the water is forced through at incredible speeds, the oceans are huge. When you started, the water level would drop by less than a centimeter per day.
There wouldn’t even be a cool whirlpool at the surface—the opening is too small and the ocean is too deep. (It’s the same reason you don’t get a whirlpool in the bathtub until the water is more than halfway drained.)
But let’s suppose we speed up the draining by opening more drains,1 so the water level starts to drop more quickly.
Let’s take a look at how the map would change.
Here’s how it looks at the start:
This is a Plate Carrée projection (c.f. xkcd.com/977).
And here’s the map after the oceans drop 50 meters:
It’s pretty similar, but there are a few small changes. Sri Lanka, New Guinea, Great Britain, Java, and Borneo are now connected to their neighbors.
And after 2000 years of trying to hold back the sea, the Netherlands are finally high and dry. No longer living with the constant threat of a cataclysmic flood, they’re free to turn their energies toward outward expansion. They immediately spread out and claim the newly exposed land.
When the sea level reaches (minus) 100 meters, a huge new island off the coast of Nova Scotia is exposed—the former site of the Grand Banks.
You may start to notice something odd: Not all the seas are shrinking. The Black Sea, for example, shrinks only a little, then stops.
This is because these bodies are no longer connected to the ocean. As the water level falls, some basins cut off from the drain in the Pacific. Depending on the details of the sea floor, the flow of water out of the basin might carve a deeper channel, allowing it to continue to flow out. But most of them will eventually become landlocked and stop draining.
At 200 meters, the map is starting to look weird. New islands are appearing. Indonesia is a big blob. The Netherlands now control much of Europe.
Japan is now an isthmus connecting the Korean peninsula with Russia. New Zealand gains new islands. The Netherlands expand north.
New Zealand grows dramatically. The Arctic Ocean is cut off and its water level stops falling. The Netherlands cross the new land bridge into North America.
The sea has dropped by 2 kilometers. New islands are popping up left and right. The Caribbean Sea and the Gulf of Mexico are losing their connections with the Atlantic. I don’t even know what New Zealand is doing.
At 3 kilometers, many of the peaks of the mid-ocean ridge—the world’s long-est mountain range—break the surface. Vast swaths of rugged new land emerge.
By this point, most of the major oceans have become disconnected and stopped draining. The exact locations and sizes of the various inland seas are hard to predict; this is only a rough estimate.
This is what the map looks like when the drain finally empties. There’s a surprising amount of water left, although much of it consists of very shallow seas, with a few trenches where the water is as deep as 4 or 5 kilometers.
Vacuuming up half the oceans would massively alter the climate and ecosystems in ways that are hard to predict. At the very least, it would almost certainly involve a collapse of the biosphere and mass extinctions at every level.
But it’s possible—if unlikely—that humans could manage to survive. If we did, we’d have this to look forward to:
1Remember to clean the whale filter every few days.
Drain the Oceans: Part II
Q. Supposing you did drain the oceans, and dumped the water on top of the Curiosity rover, how would Mars change as the water accumulated?
—Iain
A. In the previous answer, we opened a portal at the bottom of the Mariana Trench and let the oceans drain out.
We didn’t worry too much about where the oceans were draining to. I picked Mars; the Curiosity rover is working so hard to find evidence of water, so I figured we could make things easier for it.
Curiosity is sitting in Gale Crater, a round depression in the Martian surface with a peak, nicknamed Mount Sharp, in the center.
There’s a lot of water on Mars. The problem is, it’s frozen. Liquid water doesn’t last long there, because it’s too cold and there’s too little air.
If you set out a cup of warm water on Mars, it’ll try to boil, freeze, and sublimate, practically all at once. Water on Mars seems to want to be in any state except liquid.
However, we’re dumping a lot of water very fast (all of it at a few degrees above 0°C), and it won’t have much time to freeze, boil, or sublimate. If our portal is big enough, the water will start to turn Gale Crater into a lake, just like it would on Earth. We can use the excellent USGS Mars Topographic Map to chart the water’s progress.
Here’s Gale Crater at the start of our experiment:
As the flow continues, the lake fills in, burying Curiosity under hundreds of meters of water:
Eventually, Mount Sharp becomes an island. However, before the peak can disappear completely, the water spills over the north rim of the crater and starts flowing out across the sand.
There’s evidence that—due to occasional heat waves—ice in the Martian soil occasionally melts and flows as a liquid. When this happens, the trickle of water quickly dries up before it can get very far. However, we’ve got a lot of ocean at our disposal.
The water pools in the North Polar Basin:
Gradually, it will fill the basin:
However, if we look at a map of the more equatorial regions of Mars, where the volcanoes are, we’ll see that there’s still a lot of land far from the water:
[Mercator projection; does not show the poles.]
Frankly, I think this map is kind of boring; there’s not a lot going on. It’s just a big empty swath of land with some ocean at the top.
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Would not buy again.
We haven’t come close to running out of ocean yet although there was a lot of blue on the map of the Earth at the end of our last answer, the seas that remained were shallow; most of the volume of the oceans was gone.
And Mars is much smaller than Earth, so the same volume of water will make a deeper sea.
At this point, the water fills in the Valles Marineris, creating some unusual coastlines. The map is less boring, but the terrain around the great canyons makes for some odd shapes.
The water now reaches and swallows up Spirit and Opportunity. Eventually, it breaks into the Hellas Impact Crater, the basin containing the lowest point on Mars.
In my opinion, the rest of the map is starting to look pretty good.
As the water spreads across the surface in earnest, the map splits into several large islands (and innumerable smaller ones).
The water quickly finishes covering most of the high plateaus, leaving only a few islands left.
And then, at last, the flow stops; the oceans back on Earth are drained.
Let’s take a closer look at the main islands:
No rovers remain above water.
Olympus Mons, and a few other volcanoes, remain above water. Surprisingly, they aren’t even close to being covered. Olympus Mons still rises well over 10 kilometers above the new sea level. Mars has some huge mountains.
What If? Page 15