# Transatlantic Car Rental

My daughter recently received her driver's permit in the US, and aspires to visit mainland Europe someday. She has learned enough about the rules of the road to know never to drive into the ocean; however, she jokingly suggested that given a sufficient quantity of rental cars, she could eventually get to Europe by driving east repeatedly. The question is, how many vehicles would it take to build a car-bridge across the Atlantic?

Eric Munson

After extensive research, I can conclusively state that this would be a violation of your rental car agreement.

Also, you would disrupt ocean circulation in the North Atlantic, potentially seriously altering the climate in the northern hemisphere. That's very bad, although not necessarily a violation of your rental car agreement.

If you try to drive from the US to Europe, your car will stop working pretty quickly, since according to Google Maps there's a large hole between them and it's full of water. Once your car gets stuck, you'll have to leave it there and go get another one.

Driving your second car onto the roof of the sunken first one could get you a little closer to Europe. If we assume you're starting in Boston and heading toward Lisbon, using a car as a bridge would get you about a millionth of the way there, since Boston and Lisbon are about a million car-lengths apart. If the Atlantic Ocean were two feet deep, you could make a bridge out of a million cars placed end to end. Unfortunately, a quick rewatch of Titanic (1997) suggests that the Atlantic Ocean is more than two feet deep. You'll quickly have to start piling up cars in multiple layers.

At first, when the bridge would be just one or two cars high, you could stack them in a single vertical column. But as the water gets deeper, you'll need to create a wider base to keep the wall of cars from tipping over.[2] The North Atlantic current would push against the car causeway, but the tipping force from the water motion would be relatively minor compared to the pile's tendency to topple under its own weight.[3]

As you built your bridge out into the deep ocean, the cars on the bottom of the stack would be crushed. The pressure crushing them wouldn't be the water pressure. Once the windows broke and the interior of the car flooded, the pressure would equalize and the cars would hold their shape, relatively unaffected by the weight of the ocean above them. Instead, what would crush the cars would be the weight of the other cars sitting on top of them.

Even when they're underwater, cars weigh a lot. About 50% of the weight of modern cars is steel and iron, which is much denser than water,[4] so submerged cars are still quite heavy—about 60% to 70% of their surface weight, depending on their exact composition. The cars on the bottom of a mile-high stack would be subjected to extreme pressures, even greater than what they experience in hydraulic car crushers. Those crushers[5] are capable of flattening a car into a pancake a foot or two thick, and the same thing would happen to the cars on the bottom of our stack.

The first part of your bridge to Europe would be over the continental shelf, where the water is relatively shallow—just a few hundred crushed cars deep.

You'd still need a lot of cars to form this shallow-water portion of the bridge; getting out to the edge of the continental shelf would take about a billion of them, which is probably close to the total number of cars in the world. Parking lots hold about 1 car per 30 square meters, so a billion cars would cover a large portion of eastern Massachusetts.[6]

After the continental shelf, the water gets a lot deeper. The deep-ocean portion of your bridge would require a lot more cars—likely about a trillion of them. This is far more cars than exist in the world; a parking lot big enough to hold them would take up most of the Earth's land area.

So you can't rent anywhere close to a billion or a trillion cars—Enterprise, for example, only has about half a million cars in its fleet. But if you tried, you'd run into other problems, too. I got a copy of a recent Enterprise rental car agreement, and I have some bad news:

4. Prohibited Use and Termination of Right to Use.

a. Renter agrees to the following limits on use:

[…]

(4) Vehicle shall not be used for: any illegal purposes; in any illegal or reckless manner; in a race or speed contest; or to tow or push anything.

[…]

(8) Vehicle shall not be loaded in excess of Vehicle’s Gross Vehicle Weight Rating […]

(9) Vehicle shall not be driven on an unpaved road or off-road.

You'd clearly be in violation of 4(a)(9) by driving it off-road. I think you'd also be violating 4(a)(4) and probably 4(a)(8) as well. This would result in you being—at minimum—on the hook for the total cost of the rental car.[7]

Some credit cards offer coverage for rental car damage, so you might think that—if you're a high-status cardholder—you could try to get the company to foot the bill. Unfortunately, I took a look at the agreement for the American Express Centurion card, and the "What is Not covered" section clearly addresses this scenario:

What is Not Covered?

ANY COVERED EVENT BASED UPON OR ARISING OUT OF:

[…]

3. Use of the Rental Vehicle in violation of the terms and conditions of the Rental Agreement

[…]

8. off-road operation […] of the Rental Vehicle

[…]

11. intentional damage […] to the Rental Vehicle

Interestingly, American Express will also not cover damages incurred by using the rental car in a war:

[…] 1. War or acts of war (whether declared or undeclared), service in the armed forces or units auxiliary to it […]

This rule could actually end up being relevant here. Your car bridge across the Atlantic, in addition to potentially disrupting ocean circulation, would cut off shipping access to northern Europe and much of Atlantic Canada…

…which may qualify as a naval blockade.

[2] A glance at piles of cars in a junkyard suggests that they often end up in stacks with an angle of repose of 30 or 45 degrees, but a stack with a 10°-15° angle of repose at the bottom should be stable once the cars are sufficiently crushed.

[3] Mike Ashby's Useful Solutions to Standard Problems is a fantastic resource for these kinds of calculations. In this case, you could use it to figure out how a column of cars will topple, which would require an estimate of the compressibility of a stack of cars at different stages of flattening. I used specs from hydraulic car crushers to come up with my rough estimates here, but these estimates could probably be refined with experiment if you know someone with a lot of cars.

[4] Citation: You don't see a lot of anchors floating around.

[5] Most famous, of course, for imperiling George Frankly in an episode of MathNet, the detective show on PBS's Square One TV.

[6] Apparently all the world's cars would take up slightly more space than all the world's people.

[7] If you continue to operate the vehicle in such a manner, 4(d) says the company has the right to notify police that it has been stolen.

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# Hailstones

My 4 year old son and I were wondering about soccer ball sized hail today. How much damage would a hail storm with size 5 soccer ball sized hail do?

Michael Grill

When you think about it, it's honestly kind of weird that hailstones haven't killed all of us already. I mean, they're chunks of ice that plunge from the sky!

Hailstones fall from really high up. There's a popular myth that a penny dropped from the Empire State Building can kill you. The myth isn't true,[1] but for anyone who believes it, hailstones should be terrifying—after all, they often fall from the height of ten Empire State Buildings.[2]

Luckily, the same thing that saves us from falling pennies also generally protects us from hailstones: Air resistance. As they fall, both pennies and hailstones quickly reach terminal velocity, the speed at which drag balances out gravity and prevents them from speeding up any more. For a small hailstone the size of a pea or a marble, terminal velocity might be only 10 or 20 miles per hour, the speed of an object tossed across a room. Getting hit by them isn't comfortable, but it's not likely to cause serious injury.[2]

Large hailstones travel much faster than small ones and can be a lot more dangerous. The terminal velocity of a golf-ball-sized hailstone is about 60 miles per hour,[3] which could easily cause serious injury. Large hailstorms often cause extreme damage to cars, and the largest hailstones can be deadly. A storm in China in 2002 dropped egg-sized and baseball-sized hailstones that killed several dozen people and hospitalized many others.

Luckily, deaths from hail aren't very common, for two main reasons: First, because hailstones big enough to be deadly are rare, and second, because when there's a thunderstorm severe enough to produce such large hail, people generally try to take shelter.

A hailstone the size and shape of a regulation soccer ball would be more than twice the weight of the heaviest hailstones on record. It would have a terminal velocity of roughly 140 miles per hour, which is really fast. If one of them hit your car, it wouldn't just dent the body or crack the windshield, it could punch right through the roof. Sheltering indoors might not be enough to protect you, unless you had a particularly sturdy roof or possibly several floors above you.

When a hailstorm is nearby, it's good to take shelter even if you're not right below the storm. As a hailstone forms in a thunderstorm updraft, it bounces around like popcorn in a popcorn machine. Usually, it falls out of the bottom of the storm, but sometimes it's ejected out of the top or sides, then carried by wind to fall some distance from the storm. Aircraft flying near thunderstorms have been hit by hail when they have nothing but blue sky above them.

Real hailstones, especially large ones, aren't round like a soccer ball. As they tumble around in a thunderstorm, they grow via water freezing onto their sides. If they have a lump on one side, the protrusion can collect more water and grow faster than the areas around it, forming a blobby appendage. Liquid water can also run out to the edges of a rotating hailstone and freeze, forming icicle-like features.

The weird shapes of large hailstones are good news for us ground-dwellers with breakable bones, because these protrusions tend to increase their drag and lower their terminal velocity.

But the weird shapes of hailstones also raises an interesting possibility. If a hailstone had just the right combination of lobes, it's possible—if unlikely—that it might happen to form a lifting body. This strange category of aircraft—which includes the Space Shuttle, the M2-F1, and the Dream Chaser—can be unexpectedly aerodynamic despite their compact shapes, capable of gliding or even swoops.

It's unlikely that any gliding hail has ever been observed, but in the 4 billion years that Earth has had water and thunderstorms, there have probably been some pretty strange hailstones. Not only has there likely been one the size of a soccer ball …

… there might even have been one able to score a goal.

[1] Mythbusters tried it in Season 1 Episode 7 and found that the penny would really sting and make you go "ow!!"

[2] While dropping a penny on someone from the height of the Empire State Building wouldn't kill them, dropping the Empire State Building on a them from the height of a penny would, as demonstrated by the tragic demise of Jebediah Mythbuster in the pilot episode of the show eventually named in his memory.

[2] While dropping a penny on someone from the height of the Empire State Building wouldn't kill them, dropping the Empire State Building on a them from the height of a penny would, as demonstrated by the tragic demise of Jebediah Mythbuster in the pilot episode of the show eventually named in his memory.

[3] A little slower than an actual golf ball, thanks to the golf ball's greater weight and those weird drag-reducing dimples.

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# Hot Banana

I heard that bananas are radioactive. If they are radioactive, then they radiate energy. How many bananas would you need to power a house?

Kang JI

Bananas are radioactive. But don't worry, it's fine.

Bananas are radioactive because they contain potassium, some of which is the radioactive isotope potassium-40. The factoid about banana radioactivity was popularized by nuclear engineers trying to reassure people[1] that small doses of radiation are normal and not necessarily dangerous. Of course, this kind of thing can backfire.

Thanks to their use as a radiation dose comparison, bananas now have a reputation as an especially radioactive food, but they're really not. The CRC Handbook of Radiation Measurement and Protection, the source of the original data behind the banana factoid, lists lots of other foods with more potassium-40 than bananas, including coconuts, peanuts, and sweet potatoes. A large cheese pizza might be three times more radioactive than a banana,[2] and your own body emits a lot more radiation than either.

Potassium-40 decays slowly, with individual atoms sitting around for millions or billions of years before quantum randomness finally triggers them decay. Imagine you're an atom of potassium; every second you roll 21 dice. If they all come up 6s, you decay.

There are gazillions[3] of atoms of potassium-40 in a banana. In any given second, 10 or 15 of them make that all-sixes roll, spit out a high-energy particle, and become stable calcium or argon.

That high-energy particle released by the expiring potassium atom[4] will promptly bonk[5] into other atoms, leaving everything vibrating with extra heat energy. In theory, you could use this heat energy to do work—that's how the Mars rovers Curiosity and Opportunity are powered.

The Mars rovers use plutonium, which decays millions of times per second, releasing a lot of power. By comparison, the 15 decays per second from one banana work out to a couple of picowatts of power, roughly the power consumption of a single human cell. Even if you captured that decay energy with perfect efficiency, powering a house would require about 300 quadrillion[6] bananas, which would form a heap large enough to bury most of the skyscrapers in the NYC metro area.[7]

The potassium-40 in bananas is a terrible source of energy. But that's okay, because you know what's a great energy source? The banana itself! A banana contains about 100 calories of food energy, and if you incinerate whole bananas as fuel, it would only take about 10 bunches per day to keep your house running.

Unfortunately for New York City, which we buried in bananas a moment ago while trying to make the radiation idea work (sorry!), radioactivity vs chemical energy isn't an either/or thing. If you piled up a lot of bananas, they would start to release that chemical energy, one way or another. The sun-baked banana pile would start to rot. The heat from the bananas decomposing in the atmosphere would immediately swamp the heat from radioactivity. The sun-dried bananas would dry, crack, and eventually burn.

Decomposition by anaerobic bacteria deep in the pile would produce various gases, including highly flammable methane. As they bubbled up to the surface of the burning banana swamp, they could ignite; gas buildup from food waste is a major industrial explosion hazard.

So don't worry about the radioactivity in bananas. It's the rest of the banana that's the real threat. But if you're willing to risk the danger, you could power a lot more than just your house. With just a modest weekly supply of bananas—enough to cover Liberty Island in NYC…

…you could power the entire city.

[1] After nuclear engineering, this is the main pastime of nuclear engineers.

[2] Google has a handy tool for looking up the amount of potassium in foods, which even lets you select specific pizza brands. But for some reason, if you select Pizza Hut Pepperoni Pizza, your only serving size options are either "1 slice" or "40 pizzas." Nothing in between.

[3] There are about 800,000,000,000,000,000 of them, which is probably quadrillions or quintillions or something, but life is too short to sit around counting zeros and then looking up the Latin prefixes for big numbers.

[4] RIP

[5] The technical term is THUNK.

[6] Fine, I looked it up this time.

[7] It's 300 quadrillion bananas, Michael—what can it cost, 3 quintillion dollars?

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# Electrofishing for Whales

I used to work on a fisheries crew where we would use an electro-fisher backpack to momentarily stun small fish (30 – 100 mm length) so we could scoop them up with nets to identify and measure them. The larger fish tended to be stunned for slightly longer because of their larger surface area but I don't imagine this relationship would be maintained for very large animals. Could you electrofish for a blue whale? At what voltage would you have have to set the e-fisher?

So you want to give endangered whales powerful electric shocks. Great! I'm happy to help. This is definitely a very normal thing to want to do.

There are various electrofishing setups, but they all operate on the same general principle: An electric current flows through the water, and also through any fish that happen to be in the water. The electric current, through a few different physical effects, draws the fish toward one of the electrodes and/or stuns them.

For a long time, people didn't really notice that electrofishing injured fish at all. For the most part, stunned fish seemed to be fine after a few minutes. However, they frequently suffer from internal damage which isn't obvious from the outside. The electric current causes involuntary muscle spasms, which can fracture the fish's vertebrae. As this paper shows, these kinds of spinal injuries are more common and severe in larger fish.

As you mention, for a given electrofishing setup, larger fish are usually more affected than smaller ones.[1]This can lead to larger fish being overrepresented in sampling studies. Why? Well, we don't know. In their comprehensive 2003 study Immobilization Thresholds of Electrofishing Relative to Fish Size, biologists Chad Dolan and Steve Miranda modeled the way electric currents stun fish of different sizes, but caution that "no adequate conceptual system exists to explain the effects of size on electroshock thresholds from the perspective of electric fields."

None of these studies dealt with animals anywhere near the size of whales. The largest fish in Dolan and Miranda's study were still quite small. This experiment tested larger fish up to 80cm long,[2]The fish they used in the experiment grew rapidly to a range of sizes, mainly because the larger ones kept eating their smaller siblings. but nothing whale-sized.[3]There's been at least one case of dolphin death linked to illegal electrofishing. Since we don't know exactly why larger fish respond differently, it's hard to confidently extrapolate.

Fish are typically[4]Actual quote from that paper: "The results for these tests were unsettling … this observation was so unexpected that we stopped the experiment to recalibrate the equipment." stunned by equipment delivering about 100 µW of power per cm3 of body volume, so for a whale, that would be about 20 megawatts.

But there's a catch: Most electrofishing is done in fresh water. Unfortunately, blue whales live in the ocean,[5]I mean, unfortunately for Madeline. It's fortunate for the whales. where the salt water conducts electricity much more easily. That might seem like good news for our electrofishing plans, but it turns out to make it much more challenging.

Electrofishing works best when the water and the target animals are about equally conductive. In highly conductive saltwater, most of the current flows past the animals in the water rather than through them. This means that ocean electrofishing requires much more power. Using our simple extrapolation, instead of 20 megawatts, we might need a gigawatt. In other words, you'll need to bring a large nuclear generating station.

Simple extrapolation is misleading here, since we know that large animals respond to electricity differently. How differently? Well, according to an electrofishing.net post by Jan Dean, a human who fell into the water in front of a typical electrofishing boat could easily die.[6]While it sounds dangerous, people aren't often killed during electrofishing accidents. The 2000 EPA report "New Perspectives in Electrofishing" comments that "In the United States, since World War II, only about five electrocutions during electrofishing have been documented." I assume they just mean records weren't kept before World War II, but it's technically possible that the war involved so many electrofishing deaths that they need to exclude it from the stats. Blue whales, which are even larger than humans,[citation needed] would presumably fare even worse.

Electrofishing temporarily stops a fish's heart.[7]Until reading this paper, I didn't know clove oil was used as a fish anesthetic. You learn something new every day! The fish seem to recover, most of the time, but humans—and probably whales—have a harder time with cardiac arrest.

It's possible that giving blue whales massive electrical shocks isn't as good an idea as it sounded at first.

That's not to say there's no place in science for giving random electric shocks to large aquatic animals. A project at the Denver Wildlife Research Center used electrofishing-style equipment—linked to an infrared camera—to repel beavers, ducks, and geese from selected areas. Apparently, the results were "encouraging."[8]The equipment kept the beavers away, although they returned as soon as it was turned off. It also worked on ducks and geese, although they had some problems with infrared waterfowl detection. The birds would usually take flight when the equipment turned on, although if it was cold enough, they'd just sluggishly paddle away.

So electrofishing equipment probably can't help you catch blue whales. However, if you're having trouble keeping them out of your backyard pond …

… it's possible the Denver Wildlife Research Center can help you out.

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# Coast-to-Coast Coasting

What if the entire continental US was on a decreasing slope from West to East. How steep would the slope have to be to sustain the momentum needed to ride a bicycle the entire distance without pedaling?

—Brandon Rooks

Too steep to actually build, sadly. But for the next best thing, I suggest a vacation to the Hawaiian island of Maui.

First, the physics. Bikes coast downhill. On a long enough slope, a bike will reach a certain steady coasting speed. On a steep hill, their coasting speed will be faster, and on a gentle slope, they coast more slowly. If the slope is small enough, the bike will slow down and stop.

The shallowest slope at which a bike will still roll steadily forward is determined by the bike's coefficient of rolling resistance. In fact, the formula for this minimum slope—measured in terms of vertical drop over horizontal distance—is incredibly simple:

$\text{Minimum slope} = \text{Coefficient of rolling resistance}$

"Slope equals coefficient of friction"[1]Sliding friction and rolling resistance work in different ways, but the coefficients are equivalent in these types of problems. If you want to be precise, you could use the phrase "coefficient of resistance" for all of them, but "coefficient of friction" is the more common term. is a handy general rule in physics: The coefficient of friction between an object on a surface is just the shallowest slope at which the object slides.[2]The coefficient of static friction is the slope at which the object starts sliding. The (usually lower) coefficient of dynamic friction is the minimum slope at which it keeps sliding once you give it a nudge.

For a nice bike under good conditions, the coefficient of rolling resistance can get as low as 0.002, or 1/500.[3]You can browse some test data here. That means that to travel 500 miles horizontally, you'll need a vertical drop of at least 1 mile. To travel the roughly 2,500 miles from New York to LA, you'd need to start off at least 5 miles up, higher than North America's highest mountain. I suggest bringing oxygen tanks.

But be warned—the trip could take a while.

A bike's rolling resistance mainly comes from the way the tire[4]And the ground, if you're riding on dirt.[5]And the spokes and frame, if your bike is made of soft clay or something.[6]Why do you have a bike made entirely of soft clay? deforms as it rolls, and it doesn't depend that much on how fast you're going. Air resistance, on the other hand, increases as you speed up, and under most conditions is the main drag force acting on a moving bike. To figure out how fast a bike will coast on a downhill slope, you need to calculate the point at which air resistance balances out the forward pull from gravity. At that point, the bike will stop accelerating. We can do that by using the formula for air resistance:

$\text{Forward pull from gravity} = \text{Rolling resistance} + \text{Drag force}$

$m g \sin(\theta) = g \cos(\theta) C_r m + \tfrac{1}{2} C_d \rho A V^2$

$V = \sqrt{\frac{m g \sin(\theta) – g \cos(\theta) C_r m}{ \tfrac{1}{2} C_d \rho A}}$

(V is the speed of the bike, Cr and Cd are the coefficients of rolling resistance and air drag, θ is the slope angle, g is the acceleration of gravity, m is the mass of the bike and rider, A is the frontal area of the bike and rider, and ρ is the density of air.)

For a very shallow slope of 0.2° or 0.3°, the bike would barely roll, and its top speed would be slower than a walking pace. You would need to add an extra few tenths of a degree to get the speed high enough to balance comfortably, and this would make the LA end of the slope even higher than the already implausible five miles.

But still, bicycles are pretty impressive coasting machines.[7]Trains have steel wheels which roll on smooth rails, so they should have very little rolling resistance. You can work out their coefficients by looking over technical specs or calculating from first principles, but a cleverer way is by watching train-pulling athletic events. Then, with a little calculation involving the limits of human strength and/or direct measurement, you can work out the coefficient from the other end. It turns out that train cars—at least, the kind used in strongman events—have coefficients of rolling resistance barely equal to that of a good bicycle. Skis, which are pretty good at sliding, actually have a coefficient of friction about 10 times higher than a bike's rolling resistance.

To ski from LA to New York, a skiier would need to start off 10 times higher than a bike to make the same trip. Instead of the top of a mountain, they would need to start from near the edge of space. Not only is there no way to build a slope that tall, but ice isn't even stable at those low temperatures, so there'd be nothing to slide on.

In practice, the longest horizontal distance you could travel on a bike with an ideal ramp is probably not more than a couple hundred miles, and that would require ideal conditions. In the real world, the longest such trip might[8]It's billed as the longest, but I wonder if there's a longer one in some random stretch of gently-sloping downhill road in rural Mongolia or something. be the Haleakala downhill bike ride, which allows you to take a 35-mile trip from near the 10,000-foot summit all the way down to sea level with virtually no pedaling required.

(And if you can't make it to Maui yourself, you can at least enjoy the video search results for bicycle into water.)

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# Flood Death Valley

Since Death Valley is below sea level could we dig a hole to the ocean and fill it up with water?

—Nick Traeden

Yes! We can do anything we want. We shouldn't do this, though, because it would be gross.

Death Valley is an endorheic basin[1]"Big hole" in California. The floor of the valley is about 80 meters below sea level. It contains the lowest point on land in North America[2]Excluding artificial points like mines. and is the hottest place on Earth.[3]If you're about to say "Wait, what about Liby—," then don't worry, I'm with you. Just hang on and read a few more words ahead!

Now, if you're the sort of person who's into world records, you might have heard that the hottest place on Earth was Al Azizia, Libya. Al Azizia recorded a temperature of 58.0°C (136.4°F) in 1922, a mark Death Valley has never come close to. So what gives?

It turns out Al Azizia has recently been stripped of its record. In 2010, an exhaustive—and definitely a little obsessive—investigation led by Christopher C. Burt convinced the World Meteorological Organization that the Libyan measurement was probably a mistake. This left Death Valley with the record of 56.7°C (134°F), set in 1913. Case closed!

Except it's not quite settled. Burt has raised questions about the 1913 record as well, and has gone so far as to catalog a number of historical extremes along with a credibility score for each. The "real" record is probably 53.9°C (129°F). This temperature has been recorded four times, in 1960, 1998, 2005, and 2007—every time in Death Valley.

These records were recorded with modern instruments and are considered reliable. They also make sense from a theoretical point of view. Geographers have calculated[4]This Army Corps of Engineers publication cites a couple of sources for this, including a 1963 paper by G. Hoffman. Unfortunately, that paper is in German, which I can't read, so I've just decided to trust that the Army Corps of Engineers writers Dr. Paul F. Krause and Kathleen L. Flood aren't pulling a fast one on me. that the highest possible temperature in ideal spots (in desert basins like Death Valley) during the 20th century is 55°-56°C, so 54°C sounds like a reasonable world record.

Now, back to Nick's question.[5]This is nowhere NEAR the record for "most boring digression into world record trivia." That record was recently challenged by IBM computer capable of producing millions of boring pieces of trivia per second, but the machine narrowly lost to reigning human champion Ken Jennings.

Since Death Valley is below sea level, we could, as Nick suggests, flood it with seawater. It would take a lot of digging, since there's a lot of Earth in the way. The lowest route to Death Valley is probably by traveling up the Colorado River watershed, along the Arizona border past Quartzsite,[6]Trivia: If you want to reach Quartzsite, Arizona from my school, Christopher Newport University, you just step out onto Warwick Blvd (Rt. 60) and turn left. That's it—Route 60 runs across the country, from the CNU campus in Virginia to I-10 just outside Quartzsite. then northwest[7]Possibly following one of the routes shown on page G34 in this report. past Zzyzx, which is a real place.

If you did all that digging, you could create a channel from the Gulf of California to Death Valley, and water would flow in. We can use this handy stream-flow calculator to figure out how wide we'd need to make the channel. A channel 20 meters deep and 100 meters wide should be able to fill it in a few months. A really wide channel—like the kind carved by glacial floods—could fill it in hours.

We know it's possible to create this kind of inland sea because we've done it before—by accident. In 1905, irrigation engineers working on the Colorado River made some mistakes. During a flood, the entire Colorado river broke through into the Alamo Canal and flowed directly into the Salton basin to the north. By the time they repaired the canal, two years later, the Salton basin had become the Salton Sea—one of the larger human-caused changes to the world map.

The Salton Sea is fed mainly by agricultural runoff, so it's become saline[8]"Salty" and hypereutrophic.[9]"Gross" Large numbers of dead fish, combined with algal decay and unusual chemistry, have created a smell that the US Geological Survey describes as "objectionable," "noxious," "unique," and "pervasive." The sea is a birdwatching hot spot, but also the site of a lot of mass bird die-offs, so kind of a mixed bag if you're into birds. In recent years, the water has been evaporating quickly, leaving behind dried toxic residue which is swept up into dust storms. Work to clean up and rehabilitate the region is ongoing.

All in all, the Salton Sea is a mess—and Nick wants to make another one.

Nick's Death Valley project would start off connected to the ocean, but without a source of flowing water at the Death Valley end,[10](It's a desert.) the channel would gradually silt up. The link to the ocean would eventually be broken, the sea would start to evaporate, the water would become saline, algae would bloom, and eventually the US Geological Survey would start complaining about the smell.

There would be one more consequence to all this. Thanks to the flood of cold ocean water burying the whole region, Death Valley would stop setting temperature records, and someone else would eventually claim to have broken their 129°F record. The Death Valley records would have to be compared to the newer candidates, which would probably use slightly different methods … and that means one thing:

A World Meteorological Organization expert panel!

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# Flood Death Valley

Since Death Valley is below sea level could we dig a hole to the ocean and fill it up with water?

—Nick Traeden

Yes! We can do anything we want. We shouldn't do this, though, because it would be gross.

Death Valley is an endorheic basin[1]"Big hole" in California. The floor of the valley is about 80 meters below sea level. It contains the lowest point on land in North America[2]Excluding artificial points like mines. and is the hottest place on Earth.[3]If you're about to say "Wait, what about Liby—," then don't worry, I'm with you. Just hang on and read a few more words ahead!

Now, if you're the sort of person who's into world records, you might have heard that the hottest place on Earth was Al Azizia, Libya. Al Azizia recorded a temperature of 58.0°C (136.4°F) in 1922, a mark Death Valley has never come close to. So what gives?

It turns out Al Azizia has recently been stripped of its record. In 2010, an exhaustive—and definitely a little obsessive—investigation led by Christopher C. Burt convinced the World Meteorological Organization that the Libyan measurement was probably a mistake. This left Death Valley with the record of 56.7°C (134°F), set in 1913. Case closed!

Except it's not quite settled. Burt has raised questions about the 1913 record as well, and has gone so far as to catalog a number of historical extremes along with a credibility score for each. The "real" record is probably 53.9°C (129°F). This temperature has been recorded four times, in 1960, 1998, 2005, and 2007—every time in Death Valley.

These records were recorded with modern instruments and are considered reliable. They also make sense from a theoretical point of view. Geographers have calculated[4]This Army Corps of Engineers publication cites a couple of sources for this, including a 1963 paper by G. Hoffman. Unfortunately, that paper is in German, which I can't read, so I've just decided to trust that the Army Corps of Engineers writers Dr. Paul F. Krause and Kathleen L. Flood aren't pulling a fast one on me. that the highest possible temperature in ideal spots (in desert basins like Death Valley) during the 20th century is 55°-56°C, so 54°C sounds like a reasonable world record.

Now, back to Nick's question.[5]This is nowhere NEAR the record for "most boring digression into world record trivia." That record was recently challenged by IBM computer capable of producing millions of boring pieces of trivia per second, but the machine narrowly lost to reigning human champion Ken Jennings.

Since Death Valley is below sea level, we could, as Nick suggests, flood it with seawater. It would take a lot of digging, since there's a lot of Earth in the way. The lowest route to Death Valley is probably by traveling up the Colorado River watershed, along the Arizona border past Quartzsite,[6]Trivia: If you want to reach Quartzsite, Arizona from my school, Christopher Newport University, you just step out onto Warwick Blvd (Rt. 60) and turn left. That's it—Route 60 runs across the country, from the CNU campus in Virginia to I-10 just outside Quartzsite. then northwest[7]Possibly following one of the routes shown on page G34 in this report. past Zzyzx, which is a real place.

If you did all that digging, you could create a channel from the Gulf of California to Death Valley, and water would flow in. We can use this handy stream-flow calculator to figure out how wide we'd need to make the channel. A channel 20 meters deep and 100 meters wide should be able to fill it in a few months. A really wide channel—like the kind carved by glacial floods—could fill it in hours.

We know it's possible to create this kind of inland sea because we've done it before—by accident. In 1905, irrigation engineers working on the Colorado River made some mistakes. During a flood, the entire Colorado river broke through into the Alamo Canal and flowed directly into the Salton basin to the north. By the time they repaired the canal, two years later, the Salton basin had become the Salton Sea—one of the larger human-caused changes to the world map.

The Salton Sea is fed mainly by agricultural runoff, so it's become saline[8]"Salty" and hypereutrophic.[9]"Gross" Large numbers of dead fish, combined with algal decay and unusual chemistry, have created a smell that the US Geological Survey describes as "objectionable," "noxious," "unique," and "pervasive." The sea is a birdwatching hot spot, but also the site of a lot of mass bird die-offs, so kind of a mixed bag if you're into birds. In recent years, the water has been evaporating quickly, leaving behind dried toxic residue which is swept up into dust storms. Work to clean up and rehabilitate the region is ongoing.

All in all, the Salton Sea is a mess—and Nick wants to make another one.

Nick's Death Valley project would start off connected to the ocean, but without a source of flowing water at the Death Valley end,[10](It's a desert.) the channel would gradually silt up. The link to the ocean would eventually be broken, the sea would start to evaporate, the water would become saline, algae would bloom, and eventually the US Geological Survey would start complaining about the smell.

There would be one more consequence to all this. Thanks to the flood of cold ocean water burying the whole region, Death Valley would stop setting temperature records, and someone else would eventually claim to have broken their 129°F record. The Death Valley records would have to be compared to the newer candidates, which would probably use slightly different methods … and that means one thing:

A World Meteorological Organization expert panel!

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