Slashdot Mirror


Hole Drilled to Bottom of Earth's Crust

AtariAmarok writes "A new article is up on LiveScience about a hole drilled into the Earth's crust to explore the layers of our planet's substrate. The hole gets closer to the mantle than any other efforts that have gone before. The hole might reach the "Moho" (division between Earth's brittle outer crust and the hotter, softer mantle) within a few years." From the article: "The depth of the Moho varies. This latest effort, which drilled 4,644 feet (1,416 meters) below the ocean seafloor, appears to have been 1,000 feet off to the side of where it needed to be to pierce the Moho, according to one reading of seismic data used to map the crust's varying thickness."

50 of 422 comments (clear)

  1. Mr President, Dr. Evil is on the line... by TripMaster+Monkey · · Score: 5, Funny

    Good day, gentlemen...as you are no doubt aware, I have drilled a gigangtic hole straight through the Earth's crust. This hole will allow me to usher in a glorious new era of total world domination; for this reason, I have dubbed this latest caper "Operation Glory-Hole".

    You see, gentleman, the bottom of this hole is only a scant 1000 feet away from the firey liquid mantle of the Earth itself...when I detonate a small nuclear device at the bottom of this hole, Operation Glory-Hole will create a gigantic super-volcano, radically altering the Earth's climate and laying waste to civilization...that is, unless you pay me...
    ONE HUNDRED MILLION BILLION JILLION DOLLARS!!!

    /dramaticmusic

    Gentleman, you have my demands. Peace out.

    --
    ____

    ~ |rip/\/\aster /\/\onkey

    1. Re:Mr President, Dr. Evil is on the line... by Anonymous Coward · · Score: 5, Funny

      Dr. Evil is stealing my Moho baby!

    2. Re:Mr President, Dr. Evil is on the line... by AtariAmarok · · Score: 5, Funny
      "Mr President, Dr. Evil is on the line"

      Uhhh. Hi Dick. How ya doin'?'

      --
      Don't blame Durga. I voted for Centauri.
    3. Re:Mr President, Dr. Evil is on the line... by xs650 · · Score: 5, Funny

      Were you addressing Bush or Cheney?

    4. Re:Mr President, Dr. Evil is on the line... by MutantHamster · · Score: 5, Funny

      Sure, everyone's all excited about drilling a hole now, but as soon as they accidentally drill into the Earth's hollow interior and drain the entire ocean, they'll be nothing but excuses.

      --
      My Greatest Heist - Muisc partly inspired by the unbeatable Qwantz
  2. Obl Friends quote: by IainMH · · Score: 3, Funny


    Check this baby out, dug me a hole!

    --Joey Tribbiani

  3. Yay! by Anonymous Coward · · Score: 4, Funny

    I for one, welcome our moleman overlords.

    1. Re:Yay! by DrLZRDMN · · Score: 5, Funny

      shouldn't that be underlords?

  4. The More Interesting Story by Steven+Edwards · · Score: 5, Interesting

    Is the link at the bottom which talks about the idea of using a nuke to drop a probe to the earths core.

    --
    Why clone Unix when I can clone Windows instead. http://www.reactos.org
  5. Grrrreat. Let's poke a big hole in the planet. by itomato · · Score: 5, Funny

    There's no tampon made than could contain the leak that would create.

    Bad Scientists! Bad!

  6. Terraform: Construct Thermal Borehole by Rob+Simpson · · Score: 4, Funny
    +6 minerals
    +6 energy

    WARNING: Significant negative ecological impact

  7. Re:First they pearce the crust... by djdavetrouble · · Score: 5, Funny

    And then you come to the caramel lower mantle, then the delicious chocolate core.

    --
    music lover since 1969
  8. Re:is it wise? by stratjakt · · Score: 5, Informative

    That's happening all the time on the sea floor, where the plates are slowly separating.

    A bunch of lava will squish out, immediatly cool, and plug the hole, and they'll have to start all over again.

    Kind of like Cool Hand Luke.

    --
    I don't need no instructions to know how to rock!!!!
  9. China by Rylz · · Score: 5, Funny

    Pfft. I nearly made it from my sandbox to China with nothing but buckets back in my preschool days!

    --
    Sometimes you've gotta roll the hard six.
  10. Would it work? by Chemisor · · Score: 3, Interesting

    > bottom of this hole is only a scant 1000 feet
    > away from the firey liquid mantle of the Earth
    > itself...when I detonate a small nuclear device
    > at the bottom of this hole, Operation Glory-Hole
    > will create a gigantic super-volcano

    Would any geologists care to comment whether it is possible to create an artificial island this way?

    1. Re:Would it work? by dalutong · · Score: 3, Informative

      well -- i don't know if that would really be "artificial," then, since that is how many islands are formed, especially along convergent plate boundries. it is exactly as happens it happens with "hot spots." the issue would be making the hole large enough and keeping the hole open, since it would fill up pretty quickly and just make a little mountain under the sea.

      --

      What comes first, finding a teacher or becoming a student?
    2. Re:Would it work? by osmic234 · · Score: 5, Informative

      Unlikely. The Mohorovicic (Moho) discontinuity can be described in a few different ways - either where seismic veolocities have a marked discontinuity, or where a noticable chemical/mineralogical change occurs (can't remember what it is, I'm a geophysicist, not a geologist). What it's not is a boundary between a nice solid crust floating on top of "firey liquid mantle". In fact more accurate terms are lithosphere and asthenosphere, rather than crust and mantle, which basically differentiate between rigid, colder material, and warmer, more ductile rock. The top of the mantle is still solid, but becomes increasingly ductile with depth. Various minerals reach melting point as you go down towards the Core-Mantle Boundary, but basically I think you have to get to the outer core before it's all liquid (mostly iron). In terms of energies, the largest nuclear bomb ever detonated was about 55-60 megatonnes (depending on who you ask), in 1961 by the USSR. The energy released by the great 1960 Chilean earthquake (the largest recorded in the last 100 years) was equivalent approximately to a 2000 Mt bomb. So, setting off a nuke at the moho might temporarily create a small spherical cavity which would probably collapse in on itself, and maybe create some melt, but it's doubtful it would come gushing to the surface as a raging plume of "liquid hot magma". Besides, there have been plenty of underground nuclear tests, and none of those have resulted in a humungous volcano. As yet. The USGS site at http://www.usgs.gov/ is probably a good place to find out more.

    3. Re:Would it work? by Kymermosst · · Score: 4, Interesting

      IANQAG (I am not quite a geologist), but I am just finishing up my minor in Geology, and considering it as a second major.

      Unlikely. The Mohorovicic (Moho) discontinuity can be described in a few different ways - either where seismic veolocities have a marked discontinuity, or where a noticable chemical/mineralogical change occurs (can't remember what it is, I'm a geophysicist, not a geologist).

      Seismic discontinuity.

      Anyway, regarding the grandparent... in theory, the only thing keeping the mantle from melting is pressure (phase diagrams are easy to find). When you drill down, if you don't maintain pressure in the well, (again, in theory) you might be able to relieve the pressure on mantle rock and cause it to melt. Of course, you'd need a really big hole for the resulting magma to come up before it plugs itself like a puncture wound.

      Making an artificial volcano is a highly unlikely thing to accomplish, either on accident or on purpose.

      I've read one theory about the yellowstone hotspot that is related to this. David Alt and Donald Hyndman believe (found in _Roadside Geology of Idaho_) that a meteorite struck the pacific northwest and the impact crater relieved pressure on the mantle, allowing the magma to well up. This, of course, relieved pressure below and caused further upwelling. Each eruption of what is now the Yellowstone hot spot keeps the cycle going, they claim.

      I don't think it's a very probable explanation, and it doesn't seem to be easily verifiable or falsifiable, since the original evidence would have been destroyed by the volcanic eruptions.

      --
      "Alcohol, Tobacco, Firearms, and Explosives" should be a convenience store, not a government agency.
    4. Re:Would it work? by ThaReetLad · · Score: 3, Informative

      Yeah, that's the yellowstone supervolcano. Its has errupted roughly every 620,000 years, and the last one was 640,000 years ago, and last time it errupted it poured out roughly 8000 times as much ash as Mount St. Helens did in the 1980 erruption. It is estimated that if it goes again in the near future it would cover most of the US within 1000 miles of yellowstone in a thick layer of ash, killing more that 20 million Americans. It would also cause a global temperature drop of up to 10 degees C causing a new mini ice age for as long as 10 years during which time much of the worlds population would simply starve to death. I suspect we would be lucky to see as few as 1 Billion fatalities worldwide, together with the massive social and political fallout that would bring.

      The problem is that no one could know whether attempting to cause a small erruption now would in fact just trigger the real thing, because vulcanology is not an exact science, and we simply don't know enough to do such a thing.

      --
      You can't win Darth. If you mod me down, I shall become more powerful than you could possibly imagine
  11. On the drill head... by CrackedButter · · Score: 3, Funny

    ...it says "Bruce Willis woz here".

  12. Re:is it wise? by Anonymous Coward · · Score: 5, Funny

    Yes, this is exactly what will happen. Just think of it like pricking a hole in a balloon, next thing you know we are 'ppttthhhhhhhhhh' on our way to Jupiter.

  13. Screw black-holes and grey goo... by Pinkoir · · Score: 5, Funny

    ...this Dr. Evil hole is the greatest threat that mad-science presents to us.

    What happens if when they finally penetrate the crust the whole planet pops like a balloon?

    LIKE A BALLOON!!

    Think of all that crazy magma spewing out all over the place and our beloved globe zooming randomly all over the solar system before finally falling flacid and empty to the floor somewhere near Mars.

    When will these insane "geologists" learn not to poke holes in our Mother Earth.

    -Pinkoir

  14. Re:is it wise? by Planesdragon · · Score: 4, Informative

    and opening a hole will relieve that pressure and cause a large amount of it to flow out?

    Why, yes, that can happen. Mind you, "large" is only on the human scale, and this is hardly an unusual circumstance.

    What is essetnially (but not actually) mantle-juice flows out onto the crust on a somewhat irregular basis. I'm sure you've heard of it, it's quite specatcular when molten rock et al flow out.

    As for a "large ammount" -- us drilling into the mantle is like us sticking a very large straw into the ocean. Sure, the water down at the bottom is under pressure, and it will shoot up the straw if we let it. But the ocean certainly isn't going anywhere.

  15. Drilling Technology Upgrades Needed by geomon · · Score: 5, Informative

    EOS covered this recent work just recently. The problem with offset drilling is that it does not provide the same informatio as a continuous core. These cores are obtained from 'windows' in previous flows and there is a problem with correlation between boreholes when horizons are not sampled widely. This complicates the historical interpreation and genesis of the oceanic crust.

    The demand for advanced drilling technology is one problem with the current Moho sampling efforts. Exploration drilling of the kind used for oil production is not well suited for the work that the ODP is engaged in. Bit designs for the lithostatic loads that these dense rocks develop at depth require a different approach than those used to drill continental sediments buried at depth beneath the ocean.

    --
    "Rocky Rococo, at your cervix!"
    1. Re:Drilling Technology Upgrades Needed by ahfoo · · Score: 3, Interesting

      Well here seems to be someone who knows a bit about geology and drilling in particular so let me pose a question and see if you might have the time to reply.
      If these guys can drill a hole this deep in a mere three weeks and nearly hit the Earth's mantle, doesn't it seem that it should be possible to directly harness the abundant heat energy in these holes? I mean if you can make one in a few weeks it would seem you could make dozens, if not hundreds, in a year. There's got to be enormous heat if you're a thusand feet from the upper mantle and you're right next to vast reserves of cool water as well. This seems the ideal environment for a heat cycle engine.
      While not identical, the situation seems somewhat similar to the question of why we don't harness the heat energy of volcanoes. The answer I've always gotten is that it's too difficult to control a volcano.
      Certainly that's reasonable in the case of a volcano on land like Mt. Saint Hellens, but what about these mid-oceanic ridges just like where JOIDES is drilling here. In this case, it seems you can create a sort of controlled volcano. In fact, that seems to be what they're describing. Doesn't this seems like a fairly accessible source of thermal energy?

    2. Re:Drilling Technology Upgrades Needed by TapeCutter · · Score: 4, Informative

      You don't need to drill that far down to get water to turn to steam. Drill two deep holes into common granite, seperated by say 100 meters. Drop in some explosives to crack the granite between the holes at the bottom. Pump cold water down one hole and steam will come out of the other. Granite heats up because it is mildly radioactive and a single drill site can stay hot for ~50yrs. I saw this investigated on Australin TV by the CSRIO about 15 years ago but have no idea why it was not developed further.

      --
      And did you exchange a walk on part in the war for a lead role in a cage? - Pink Floyd.
    3. Re:Drilling Technology Upgrades Needed by jaakkeli · · Score: 3, Insightful
      If these guys can drill a hole this deep in a mere three weeks and nearly hit the Earth's mantle, doesn't it seem that it should be possible to directly harness the abundant heat energy in these holes?
      So, you drill a hole, put some pipes to bring water there and up. Bringing the heat up will obviously cool the rock that touches your pipe, but as the rock cools, your power production drops. You can only produce energy sustainably if you limit the rate to such that the heat transfer from the rest of the crust is fast enough to balance the cooling. And even if it is really hot down there, the stuff isn't necessarily a good conductor of heat, so this can be a severe limitation to power production. Remember all the nature films where you've seen underwater lava flows: once the stuff starts pouring into water, the surface will solidify quickly, but the inside will be hot for a long time. It's because the water cools the surface fast and the heat doesn't transfer equally quickly to the surface of the rock.
    4. Re:Drilling Technology Upgrades Needed by cheesybagel · · Score: 4, Informative

      Find all about Hot Dry Rock geothermal energy here.

  16. Wait a minute... by darkitecture · · Score: 3, Insightful


    Wait a minute...

    Are you trying to tell me that this whole damn time, we've never broken through the earth's crust and seen the mantle for ourselves? We can send something 8.7 billion miles away but we can't drill two miles down? Doesn't this strike people as a bit odd or disconcerting?

    Personally I'd like to learn just as much about the earth under my feet as the stars above my head.

    I'd like to see this get more funding and see us reach the mantle in the next few weeks instead of waiting for some time in the "coming years."

    1. Re:Wait a minute... by dragons_flight · · Score: 4, Informative

      Drilling two miles isn't that hard and has certainly been done before. The deepest drill hole on land goes down some 12 km.

      But this isn't the same thing. This is trying to drill down 3+ km below the bottom of the Atlantic. In this case the drilling starts under 750 m of water (and only because Atlantis Massif is a relatively high spot on the sea floor). The mid-ocean ridge in the Atlantic is their target because it has some of the shallowest Moho in the world. To reach the Moho from a continental section you would probably have to drill 25 km or more even with a good choice of location.

  17. Hole's Enemy by Chubby_C · · Score: 5, Funny

    Don't forget the hole's only natural enemy is the pile

    --
    - My question is: Can Slashdot be Slashdotted? -
  18. Re:First they pearce the crust... by caryw · · Score: 4, Informative

    Here's a diagram of Earth's layers:
    http://earth.usc.edu/~stott/Catalina/images/plate% 20tectonics/Earthcore.jpg

    My only question is what if the enormous amount of pressure from the mantle forced tons of lava to shoot into the ocean? Or in reverse what if the pressure of the ocean was greater and we open a giant drain in the middle of the atlantic?

    Would the lava/water contact just harden to rock instantly and allow nothing more through?

    Probably quite ignorant fears, but still worth asking.
    --
    Fairfax Underground: Message boards and Chat for residents of Fairfax County and Northern Virginia

  19. Re:is it wise? HAWAII!! by Thunderstruck · · Score: 4, Funny

    The same way we got the Dakotas. We walked up to the natives and said hey, lets have a treaty...

    --
    Trying to use sarcasm in text-based forums does not work.
  20. Re:First they pearce the crust... by TedCheshireAcad · · Score: 3, Funny

    ... then they reach the mantle? Did I get that right?

    No...everyone knows we reach China before anything else.

  21. Didn't Dr. Dana Andrews do this back in '65? by drphil · · Score: 3, Interesting

    Damn near killed us all as I remember it.

  22. Re:Help me out... by Decaff · · Score: 4, Informative

    But how smart is drilling into the core of the earth? Aren't they asking for one huge volcano?

    No, as magma is coming up to the surface all the time all over the world in holes much, much larger than the borehole.

    If someone who was hell bent on one HUGE suicide bomb, what is to stop a country from picking 4 or 5 places around the world, dig deep, and pack a nuke. Blow up the nuke, and the earth is rearranged.

    Nothing much would happen. The energy already being released by normal volcanoes and earthquakes is far more than we could produce with nuclear weapons. For example, the Mount St. Helens volcano released energy in just one day (18 May 1980) equivalent to 400 million tons of TNT - about 20,000 Hiroshima bombs. That is a significant fraction of the entire world's current nuclear arsenal - from just one volcano! A few nukes exploded around the world is not going to do anything.

  23. Re:Help me out... by EtherAlchemist · · Score: 4, Informative


    Aren't they asking for one huge volcano?

    No. Well, maybe in the movies.

    Think about it for a second. All over the world there a thousands of holes that already lead to the molten material, and yes- they are volcanoes.

    BUT, how many of those are constantly spewing molten rock? Relatively few. And some of those are so consistent in their eruptions people live on them. Hawaii for one, Iceland another.

    When a volcano like Tambora (largest recent) or even Fish Canyon or Yellowstone (28 million and 1.3 million YA, respectively) went off, the earth wasn't "rearranged." Sticking a nuke in a relatively tiny hole wouldn't even really have a major impact on the local area. It certainly wouldn't cause the kind of damage you're talking about. How many times have nukes been tested underground, or even above? The damage to the earth was minimal. It was all the things around the blast that suffered damage.

    Worst case scenereo and the USA is relocated to the moon.

    Unlikely, Fish Canyon only ejected about 5000 cubic kilometers and it was in the USA which is, obviously, still here.

    --
    R(k)
  24. Re:First they pearce the crust... by smoketetsu999 · · Score: 4, Insightful

    I doubt it, worst case scenario? They create a new volcano. Volcanos usually start underwater and build up in time when it flows and cools into new layers. There are small underwater volcanos all over the ocean.

  25. Re:At what cost? by MillionthMonkey · · Score: 5, Insightful

    Your tax dollars at work. How much money did this cost?

    Here we go again.

    In order to avoid these inevitable comments that appear in every thread with a scientific topic, I suggest that no international research project be allowed to proceed unless it has been cleared by a panel of Anonymous Cowards who have been convinced after watching the teevee for too long that all science is really a scam to squander their tax dollars on foolishness like basic research that shows no promise of an immediate economic benefit such as a drug that makes your peepee harder.

    In response to your question, you might be able to maintain a botched occupation for a few hours with the money.

  26. Re:Let the mantle come to us... by GeoGreg · · Score: 4, Informative

    The stuff that comes out of volcanoes is not pure mantle material. In fact, usually it's melted crustal material. Or some mixture of mantle and crustal material. Only occasionally do volcanoes cough up a hunk of mantle. More usually, we can look at pieces of mantle that may have gotten caught up in some tectonic process and been uplifted for us to see. But that's rare, and the rocks are often altered by other processes.

  27. Wal-Mart and IKEA by failedlogic · · Score: 4, Funny

    How long before Wal-Mart and/or IKEA uses drilling holes through the Earth to reduce supply-chain management costs. I envision, there could be a hole going from China to California and/or Seattle.

    How much heat can those RFID tags resist anyways??!

  28. Re:is it wise? by perspicaciously · · Score: 5, Interesting

    The pressure inside the balloon is much greater than the pressure outside the balloon

    The pressure outside the balloon is the same as the pressure inside the balloon. The reason balloons expand when you fill them with air is so that they equalize the pressures. Since the balloon is made of an elastic material without a rigid structure, maintaining equal pressures on either side of the membrane is the configuration that requires the least energy. As the balloon becomes really inflated, the latex can't stretch easily, and it does compress the air inside--but not much, just 5 or 6 mm of mercury.

    when you prick it, the pressure equalizes, causing the balloon to pop

    The "pop" isn't really related to the pressure equalizing. The latex is under high hoop and axial stress, and when it gets pricked, the hole that forms breaks lines of stress and the latex gets pulled away from the hole. This tears the latex, very rapidly--considerably faster than the speed of sound. The ends of the latex are under so much stress that they contract as fast as the tears occur, and create a small shockwave/sonic boom. When put scotch tape on the balloon where you prick it (before pricking it, of course), the strain around the hole isn't enough to start the tears, since that also requires tearing the scotch tape (or tearing away from it).

    However, you're very right that we can't compare this to the earth, because the crust of the earth certainly isn't under high uniform elastic tension attempting to maintain internal and external pressures.

  29. Doubtful... by Pyrosophy · · Score: 4, Interesting

    Unless you live in Chile or Argentina. Check out the antipodes map to see where you'd end up.

  30. Sounds from Hell by Alien54 · · Score: 5, Interesting
    This reminds me of the urban legend that makes the rounds about scientists drilling into the earth being startled by the sounds of hell emerging from the pipe. Complete with escaping bat or demon emerging from the pipe.

    Click here for info on how this story really came about.

    Someone finally did the leg work to track the story down. On the other hand, I would like to find the source of the Audio Clip.

    --
    "It is a greater offense to steal men's labor, than their clothes"
  31. Re:is it wise? by The+Archon+V2.0 · · Score: 3, Funny
    Yeah, we're screwed now. Start working on your lava-boats everyone....

    People? Boats? Endless seas of lava? Oh, great. If one person in Hollywood reads that, we're in trouble.

    "Now in theaters: The sequel to smash hit Waterworld: Fireworld!"

  32. Re:Help me out... by Decaff · · Score: 4, Informative

    Cannikin - a 5 megaton ABM warhead detonated underground in Alaska - caused the equivalent of a 6.5+ earthquake, with part of the island it was detonated under being permanently raised, and a long section of coastline falling into the sea.

    The CGS and USGS play this down a bit, and I'm not entirely sure why.


    Because this did not happen. There was no earthquake. There was a ground wave produced by the blast which, close to the site, was similar to the ground wave which would have been detected over a much wider area if there had been an earthquake, but there was no quake, either locally or elsewhere.

    Of course a small part of the island close to the blast was raised - this is what happens with underground explosions! But, the main effect was a 40-foot deep crater. As for a section of the coastline falling into the sea - I can find no evidence or reports of this anywhere.

  33. Moho or Soho? by Easy2RememberNick · · Score: 4, Funny

    "Moho" (division between Earth's brittle outer crust and the hotter, softer mantle)

    Not to be confused with Soho, NY where the bitchy upper crust and the hot artsy type meet.

  34. Re:is it wise? by Kadin2048 · · Score: 4, Informative
    Huh? Certainly you don't think that if you stick a straw down to the bottom of the ocean, that water will flow UP it, higher than the surface of the water up above...do you?


    If you do, then you should review some basic physics concepts. The pressure differential that exists between the water on top of the ocean and at the bottom would also exist between the bottom of the pipe and the top. So you would have exactly the same level of water inside your straw, as you would outside. Just like in a bottle of Coke or something. Putting one end of the straw at the bottom of the bottle doesn't cause the soda to come shooting out the other end towards your face (although it would be funny if it did, wouldn't it?).


    The only exception is if you were to lower the 'straw' down while filled with air (by keeping the top closed and equalizing the pressure against the water using compressed air) and then when you got down to the desired depth, releasing the cap on top -- this would cause water to rush in the bottom to equalize the fluid levels between the inside and outside of the pipe. If the differential is big enough it may in fact be moving quickly enough to 'overshoot' the water level of the ocean and come out the top of the pipe, but this is temporary only -- the steady state solution is with both fluid levels equal.


    If you don't believe me, go get a clear straw and a glass of water and come back when you've tried it.

    --
    "Ladies and gentlemen, my killbot features Lotus Notes and a machine gun. It is the finest available."
  35. Re:Help me out... by Decaff · · Score: 3, Informative

    There were many, many aftershocks after the main one. It's been about a decade since I took a geology course, but I have difficulty envisioning how this could occur if there wasn't some sort of tectonic activity involved.

    There was no shock! It was a local ground wave, not an earthquake. There may have been slight aftershocks at the site, as rock caved in to the hole generated by the blast. There were no earthquakes, and no tectonic activity - the blast was 5 megatons, which is absolutely negligible compared to the energy in even the smallest quake.

    You can see footage of it in Atomic Journeys (the third film in the "Trinity and Beyond" series). It also has some excellent shots of the huge cracks opened by Faultless.

    Well, big bombs will open cracks, but these are nothing on the scale of tectonic events.

    I have not seen the film, but I don't rate a single movie narrated by William Shatner as a definitive source of scientific information. It may be true, but I don't consider that useful evidence.

  36. Re:is it wise? by Afrosheen · · Score: 3, Informative

    Way to skim over my post and the grandparent's post and miss what I was commenting on previously. My last post was in repsonse to the statement "The pressure outside the balloon is the same as the pressure inside the balloon". I don't think that's true if the balloon wants to pop when you stab it with something. An uninflated balloon is the only kind with equal pressure inside and out.