1040: "Lakes and Oceans"

[Maurog]

Air density at pressure of 800 atm is 570.4 kg per cubic meter. *
Since water density is 1000 kg per cubic meter, the supercondensed air bubble will float.

According to Wolfram Alpha, you need a pressure of about 5090 atm to compress air enough for it not to float in water.

[kest23]

This reminded me of this: http://img27.imageshack.us/img27/2033/1277552972510.jpg (I'm not sure if this is the original - it's the best version I found on Google.)

[bmonk]

I was amused by the inclusion of the Edmund Fitzgerald. And that reminded me of the attempt to get Lake Champlain listed as one of the Great Lakes, which was responded to by an offer to sell New York and Vermont a used ore carrier, which they could use as a bridge over their lake.

[zen1mada]

So, I would very much like a poster of this to put in my lab. We do acoustic bathymetry among other things, and it would be great! Any idea on when that could happen?

[arthad]

I'm not sure if I'm missing something, but there appears to be a discrepancy with the scuba and submarine depths. According to Wikipedia, the record depth for scuba dive on compressed air is 509 feet (155 m). Also according to Wikipedia, the test depth for the Typhoon-class nuclear submarine is 1,300 ft (400 m). Obviously the nuclear submarine can go far deeper than record-breaking scuba divers. But the image seems to show the record scuba depth as just slightly deeper than the Typhoon-class sub, and the Ohio-class sub as being about half as deep as the record scuba depth. What gives?

[ckbryant]

Who is Burt Khalifa?

[Nomic]

If'm suprised at the deepest oilwell being that deep. Usually oil can only from in the depth of a few kilometers, since when you go deeper the heat causes it to turn into natural gas and asphalt. The Kola superdeep borehole is pretty much the deepest we can go with conventional equipment, because at that depth the heat combined with the heat generated by the drill spinning is enough to cause the drill to become too soft to penetrate rock.

[Lieutenant Geyser Shitdick]

I'm not sure I get the door James Cameron opened reference. I can't find any article about an actual door, and I can't get what he's talking about otherwise. Hints?

I believe it's a reference to this comic: http://xkcd.com/969/

[arto7]

The Ballmer peak references a talk that Mr. Munro gave at Google in 2007. Someone else posted a picture of the graph as a spoiler. Here is a link to the video of the talk. http://youtu.be/zJOS0sV2a24

[mekily]

For all those wondering about the James Cameron reference:

James Cameron's Submarine Trip to Challenger Deep
http://www.nytimes.com/2012/03/26/science/james-camerons-submarine-trip-to-challenger-deep.html

[cream wobbly]

Punctuation Error: "So presumably there are big squid down there?" is marked as a question when it is a statement and should therefore end with a period. If it was* a question it should be, "Are there big squid down there?".

Question marks mark questions.

* Subjunctive mood is archaic and should be forgotten to make subject verb agreement more consistent.

It may have passed you by, but Ænglisc áleofaþ. For the last 250 years or so, it's no longer necessary to append "are there" to the end of a statement of presumption to turn it into a question.

[nitePhyyre]

For all those wondering about the James Cameron reference:

James Cameron's Submarine Trip to Challenger Deep
http://www.nytimes.com/2012/03/26/scien ... -deep.html

Thank you! That cleared everything up.

[hg00000]

Who is Burt Khalifa?

It's the Burj Khalifa (formerly known as the Burj Dubai), the tallest building in the world.
http://en.wikipedia.org/wiki/Burj_Khalifa

[afecks]

Sperm Whale depth is listed in the strip as 3,000 meters, but based on an article by the National Marine Mammal Laboratory (http://www.afsc.noaa.gov/nmml/education/cetaceans/sperm.php), it's approximately 3,000 feet.

[okalokee]

I love that the *third* comment posted here (about clarifying the depth of the Deepwater Horizon oil well) was exactly the one I was going to make. So I'll just add some more information: The depths shown in the chart seem to be from when Deepwater Horizon was drilling the "Tiber" well:

sealevel to seabed: 4,130 ft / 1,259 m
sealevel to oil: 35,050 ft / 10,683 m

The "Macondo" well, which is where the famous blowout and oil spill happened, was much shallower:

sealevel to seabed: 5,067 ft / 1,544 m
sealevel to oil: 18,360 ft / 5,596 m

Fun figures here:
http://www.energybulletin.net/stories/2010-05-21/what-caused-deepwater-horizon-disaster

[Ponycakes]

I need either clarification or correction regarding today's comic.

The illustration shows that the SCUBA record is BELOW the rating of a Typhoon-class submarine. When I realized how odd that was, I did some leg work and found that the Guinness World Record for SCUBA is 318.25 meters, while a Typhoon-class submarine is test rated to 400 meters.

Please clarify?

Reference:
http://www.scubarecords.com/
http://en.wikipedia.org/wiki/Typhoon_class_submarine

[project2051]

Today's comic is the pits.

I thought it was quite deep.

[Klear]

The Ballmer peak references a talk that Mr. Munro gave at Google in 2007. Someone else posted a picture of the graph as a spoiler. Here is a link to the video of the talk. http://youtu.be/zJOS0sV2a24

Eh... could I you provide a more explicit explanation? The video has almost an hour and there are no speakers where I sit right now anyway...

[sardia]

For all those wondering about the James Cameron reference:

James Cameron's Submarine Trip to Challenger Deep
http://www.nytimes.com/2012/03/26/scien ... -deep.html

Thank you! That cleared everything up.

That's not the whole story. The other part about the door in the deep is a reference to a choose your own adventure book.
http://www.amazon.com/You-Genius-Choose ... 0553281550
In one of the options, you make a submarine that can travel into challenger's deep. There, you find a mysterious door, which you enter and the book ends.

[keithl]

Another Fun Fact:

At pressures greater than 70 atmospheres (a depth of 700 meters in seawater), at the temperature of deep seawater (about 4C), CO2 is a liquid. At pressures greater than 300 atmospheres, compressible CO2 liquid is denser than seawater. If you filled a balloon with CO2, and released it below 3000 meters depth in the ocean, it would fall to the bottom, about 5% denser than seawater at 6000 meters depth.

With enough energy (on the order of 1E21 Joules, a whole lot), you could process the excess CO2 out of the atmosphere and store it in a covered pool down there, on the order of 1000 cubic kilometers for the current excess of 200ppm (compared to prehistoric 180ppm). Uncovered, it would eventually dissolve into the seawater and kill the ocean.

I've been thinking about this lately, see: http://server-sky.com/OceanStoreCO2. Not making excess CO2 would be better, and not replacing giga-hectares of CO2-absorbing wild habitat with tilled agriculture, pavement, reservoirs, solar cells, etc. would be better still, but we like our power plants and hamburgers and sustainability theater. Plan Sea might be better than plan 40C. Temporary storage until we develop better energy sources, and separate it into carbon and oxygen again.

[skeptical scientist]

And when will the poster be available?

So, I would very much like a poster of this to put in my lab. We do acoustic bathymetry among other things, and it would be great! Any idea on when that could happen?

In my experience you're unlikely to get official answers to these sorts of questions on the forums.* You can try emailing orders@xkcd.com for an official answer.

It took the "Narrative Charts" comic four months to appear as a poster, and "Gravity Wells" became a poster after two months. Those were the only two posters that I could check when they appeared in the store, although the "Money" poster went up for preorder immediately. Possibly there will be a pre-order announcement shortly with a more definite timeline.

*Although this isn't always the case, and I'd be happy to be proven wrong.

[BlitzGirl]

I presume the Russians stopped drilling their hole through the center of the Earth because they realized they would emerge not in China, but in the middle of the Southern Ocean. I know I was disappointed when I found out that only South Americans could make it to China that way.

http://www.freemaptools.com/tunnel-to-o ... -earth.htm

[Joepat]

Reminds me of the Gravity Well comics.

[Willl]

Air density at pressure of 800 atm is 570.4 kg per cubic meter. *
Since water density is 1000 kg per cubic meter, the supercondensed air bubble will float.

According to Wolfram Alpha, you need a pressure of about 5090 atm to compress air enough for it not to float in water.

Not quite...

At 5090 atm, air might weigh 1000 kg/m³ but water now weighs 1155 kg/m³. It's not totally incompressible.

So of course the question is then, "at what pressure does air catch up water in density?"

Turns out that at room temperature, water freezes at 8800 atm, just before which it weighs 1225 kg/m³, while air still only weighs 1135 kg/m³. After some iteration with Wolfram Alpha, it appears the water has to be at 85°C to stop it freezing, and pressurised to 19700 atm. Then both air and water weigh 1325 kg/m³, and bubbles will sink.

I fully expect someone else to step up at this point and point out some weird-ass phenomenon that happens at this pressure though...

[el_abeja]

I just wanted to thank Randall Munroe for this comic (if you happen to see this anyway). I teach science, and we are currently studying the Earth's crust. The students started asking questions today about the bottom of the ocean, so I showed them this comic. It led to a great discussion! Thanks!

[Arcteryx]

Long-time reader, first time poster.

Surprised that Lake Vostok didn't make this graphic:

Lake Vostok is located at the southern Pole of Cold, beneath Russia's Vostok Station under the surface of the central East Antarctic Ice Sheet, which is at 3,488 metres (11,444 ft) above mean sea level. The surface of this fresh water lake is approximately 4,000 m (13,100 ft) under the surface of the ice, which places it at approximately 500 m (1,600 ft) below sea level. Measuring 250 km (160 mi) long by 50 km (30 mi) wide at its widest point, and covering an area of 15,690 km2 (6,060 sq mi), it is similar in area to Lake Ontario, but with over three times the volume. The average depth is 344 m (1,129 ft). It has an estimated volume of 5,400 km3 (1,300 cu mi).

Kind of tricky with the whole above sea level/below the ice cap, though.

[helo darqness]

Just to the left of the Titanic lines is an unnamed white line. Anyone know what that is?

[quillsinister]

I have to keep staring into the abyss. That's where they keep all of the really interesting monsters.

[arto7]

The Ballmer peak references a talk that Mr. Munro gave at Google in 2007. Someone else posted a picture of the graph as a spoiler. Here is a link to the video of the talk. http://youtu.be/zJOS0sV2a24

Eh... could I you provide a more explicit explanation? The video has almost an hour and there are no speakers where I sit right now anyway...

OK, but grudgingly since you apparently neither read lips nor have closed captioning option on YouTube which makes you ludditeish. I apologize for the spelling os ludditeish as I have never seen the word before. Click away.

Spoiler:

At approximately 8:50 in the video he starts talking about programming ability as a function of blood alcohol content. He shows that the more you drink the worse your programming gets until a spike occurs, that is, your ability suddenly increases to a higher level than when sober. So the important thing is to drink enough to hit the spike precisely but not go over because then your ability crashes again - go "a little off the spike and you end up with Windows ME." The spike occurs at .1337 BAC. I am not really sure about what was meant by the Ballmer Peak easter egg. There appears to be a line at -1337 and someone noticed it is sort of under the champagne bottle reference. The depth is marked on the chart but not as Ballmer anything. I think it is more likely a reference to 1337 = leet = elite. The Ballmer curve was the same reference to mad skillz. Sorry if I sucked any fun out of this. I am at about .1338 BAC now and am just going to mark this spoiler and move on. Extra spoiler, I am exaggerating my BAC.

[RhinoDriver]

A couple of extra surface elevation errors:
Crater Lake: 1883m
Great Slave Lake: 156m
Lake Baikal: 456m

Potential significant add:
Lake Titicaca: surface elevation 3812m (depth: 281m)

[captnemo]

Trying again. Just registered to say thanks Randal for the most awesome xkcd comic ever.
I was hoping for a mention of Devils tower or Perdidos spar, but I guess you can't include everything.
Can't wait for the poster.
Oh and Hi Sangura!
-CaptNemo

ps including lake titticaca would have been pretty cool so I'll second that

[JMan152]

Why is Crater Lake's surface at sea level? I always thought it was crazy that it's such a deep deep lake and yet the bottom is still above sea-level. Hail Mount Mazama!

[Sir Lunch-a-lot]

At least in my vsn of Chrome, can't get hi-res version of image. Just the small png; can't read the text. Links please?

Here it is: http://xkcd.com/1040/large/

Sooo... what exactly is the difference between water rushing in and air rushing out?

The air doesn't rush out. It gets compressed and pushed further in. Normally you'd expect air to rush out until the pressure is equalized, then for air to continue leaving while water enters. At that depth, no air leaves, but water still enters.

It's.. not just that there's 10 pounds of shit in the 5 pound bag, it's that there's now an extra 30 pounds of shit being crammed in on top of the 10 pounds in the 5 pound bag.

Seconded. Here's another way to think about it: Imagine that you're the scuba diver, with lungs full of air at the same pressure as the water around you. If you dive below this line then when you open the flow valve from the tank the air in your lungs would get compressed into the canister instead of flowing out like you'd want it to. That line is therefore the theoretical maximum scuba depth, based on Randal's research into scuba tanks. There are other practical limits, like oxygen and nitrogen poisoning, or the anesthetic effect of noble gasses like Helium; these explain why the scuba record is nowhere near the tank pressure line.

I'm amusing myself, however by imagining that the pressure limit were the only one we were concerned with. A scuba tank could be charged far beyond its rated surface capacity if we could pre-position it at great depth and fill it on-site using hoses from the surface. Such a tank would explode if brought to the surface without depleting the air, but as long as it stayed submerged the water pressure would compensate for the extra air pressure keeping it safe for use during the dive. And now I can rest contented that I've solved a problem that no one will likely ever encounter

Bear in mind that beyond a certain depth/pressure, the standard mix of air you and I breath here at the surface (I assume you don't live in an awesome undersea city) becomes poisonous to humans. As such, they actually breath a Helium Oxygen Air Mixture.

On a slightly related note, I think it would be neat to have a high pressure glass domed city under water with the gas pressure equalling that of the surrounding water pressure (although, I wonder how tall the dome could be before you start running into issues of pressure differential between the top and bottom?) so that you wouldn't need to worry so much about the glass/plexi/transparent-aluminum cracking/leaking.

[Corpus]

Kola borehole: Soviet project [...] Russians are awesome.

Isn't there a difference between being Soviet and Russian?

[plankton pie]

Spoiler:

As Randall stated in a talk at... some university, the Ballmer peak lies between 0.129 and 0.138% BAC. These are rounded values, the actual peak lies at a BAC of 0.1337%.

The unmarked line in today's comic lies at a depth at exactly approximately 1,337m depth.

I didn't want to spoil the surprise, but apparently I've been a bit too cryptic

Hope that clears up any confusion

They are pretty close, aren't they?


Hello, new here. I don't get the Ballmer Peak reference either. Help? What is the connection between the depth diagram and the Ballmer Peak blood alcohol concentration?

[plankton pie]

Also, sorry if I'm being slow, but:
i) why is the Marianas Trench shown in brown, and not in black to indicate that it is in the ocean?
ii) what are the horizontal diagrams of the Marianas Trench and the Mauna Kea supposed to indicate?

[GulliNL]

Also, sorry if I'm being slow, but:
i) why is the Marianas Trench shown in brown, and not in black to indicate that it is in the ocean?
ii) what are the horizontal diagrams of the Marianas Trench and the Mauna Kea supposed to indicate?

For me (to answer your number 2) it made very clear that when you look at a map and you see a point at almost 11.000 meters below sea level, it doesn't mean it's a chasm per se. Apparently the gradient of the 'walls' of challenger deep aren't that steep at all. It's a nice reference point, for me at least it is.

Also I think Mr Munroe wants to point out the actual height of Mauna Kea when you would drain the ocean, which is pretty high in fact.

[Tharwen]

Also, sorry if I'm being slow, but:
i) why is the Marianas Trench shown in brown, and not in black to indicate that it is in the ocean?
ii) what are the horizontal diagrams of the Marianas Trench and the Mauna Kea supposed to indicate?

i) It's brown because the deep bits are stacked over the shallow bits to save space.
ii) That their sides are not very steep.

[J L]

I don't get the Title Text. "James Cameron ... didn't know its song would be so beautiful. He didn't close the door in time. He's sorry." Song? Door? (Obviously referencing the door in the comic, but I get the feeling it's referencing something else, too.) Anyone have a clue to spare?

That damned "song could be so beautiful" quote has been on the tip of my tongue since Monday, and still I'm stuck, and my Google-Fu fails me. It should be some SF&F reference to things-better-not-known-to-man, like "Don't look into the light" -- actually anything from Lost to Poltergeist. Please, anyone ...? I do feel guilty for asking.

[VectorZero]

Hello, new here. I don't get the Ballmer Peak reference either. Help? What is the connection between the depth diagram and the Ballmer Peak blood alcohol concentration?

1337 is hacker slang for elite. (I assume most people know this, but figure it's best to be safe)
The Balmer Peak (1337 programming skillz) occurs at a blood alcohol level of 0.1337%
On the depth diagram there is a mark at 1337ft.
That mark's horizontal location also roughly corresponds to 0.1337 on the x-axis of the Ballmer Peak comic when the two are overlaid.

Intentional or not? You be the judge.