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Science

The World's Longest Cave System Just Got Even Longer (livescience.com) 82

schwit1 shared this report from LiveScience: The world's longest known cave system just set a new record after surveyors spent hours mapping an additional 8 miles (13 kilometers) of the passageways at Mammoth Cave National Park in Kentucky.

The corridors at Mammoth Cave now measure a whopping 420 miles (676 km) in length, according to the National Park Service (NPS). That's about the distance between New York City and Raleigh, North Carolina.

Mapping the cave system was a huge undertaking, carried out by volunteers at the Cave Research Foundation (CRF), a Kentucky-based nonprofit group, and other locals, including those from the Central Kentucky Karst Coalition. "Many of the cave trips are long and arduous, involving climbing, vertical exposure, squeezes, crawlways, water and mud," Karen Willmes, the eastern operations manager with CRF, said in an NPS statement... "After the trip, cartographers turn the data collected on the cave trip into a map. Other volunteers provide surface support.

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The World's Longest Cave System Just Got Even Longer

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  • I have a special research project in mind, and bat poo is essential.
    • I don't know the specific laws in the USA, but here in Britain cavers generally try to avoid using passages where bats roost, and have done for decades. That's not actually too difficult - bats can fit into bits of cave smaller than even the infamous "undernourished dwarf" members of cave search teams. About 20 years ago it became a specific criminal offence to knowingly disturb a bat roost, but the cavers were already avoiding bats when they noticed them. I don't think that a single caver has been prosecut
  • Retarded headline (Score:4, Informative)

    by RightwingNutjob ( 1302813 ) on Sunday September 26, 2021 @11:46AM (#61834115)

    The cave is as long today as it was last week.

    • by dfghjk ( 711126 )

      Hysterical, but not even representative of how bad /. editors actually are. Funny how a site for nerds cannot employ editors that understand English.

      • Do you actually think the editors do much editing? From my submission history, I'd say that about 10% of them get significant editing - and that is mostly cutting and pasting my submission with someone else's on the same topic.
    • There's still water flowing through the cave so I suspect it actually does get slightly larger every week although such minor changes in size are difficult to measure.

      The tour I took as a kid left quite an impression on me. That's where I learned the difference between stalactites and stalagmites and how they were formed. And I saw the water still dripping and leaving small mineral deposits so if those things were still growing, I suspect the cave is still growing as well. Just very slowly as such things d

      • There's still water flowing through the cave so I suspect it actually does get slightly larger every week although such minor changes in size are difficult to measure.

        Hydrology is the science of water resources. A lot of the science was established in limestone areas, trying to understand where the water went and where it could be found in drought.

        One of the first things cavers do on assessing a new area (which does happen, normally because of politics changing) is to start mapping underground watersheds (

  • If even in a well-explored cave like Mammoth you can still find 13km of new caves surely we should be calling it the longest known system since it seems there is a possibility that there may be longer systems out there that we have not found yet.
    • It's a near certainty that there is. There's a fair chance that many the cave systems of Yorkshire all link up along the Craven Faults, which would link several hundreds of km of survey into one system, by adding just a few hundred metres of survey. Odds on, that survey would probably be underwater, but connections made underwater have a habit of inspiring the diggers to get busy on moonless nights.

      If you look at the various "awards" in various countries, they are for greatest length of survey, not for len

  • by 140Mandak262Jamuna ( 970587 ) on Sunday September 26, 2021 @12:28PM (#61834251) Journal
    We already knew the Mammoth Cave had 420 miles of passages. 8 more miles is less than 2% of it. In other words, the cave system grew by 2%. Unless we have the next biggest cave system withing striking distance, say 400 miles, the claim for the title it would look like.

    But two cave systems in Mexico #2 and #4 in the world are 240 miles and 200 miles in size, and they are just 30 miles apart as the cros flies. Google map link below. If they find a passage connecting the two, they will take number 1 spot.

    https://www.google.com/maps/di... [google.com]

  • Was there years ago (Score:4, Interesting)

    by 93 Escort Wagon ( 326346 ) on Sunday September 26, 2021 @12:59PM (#61834359)

    I've only done the tourist thing - I'm not a spelunker - but even given the typical touristy vibe of the public parts, it's pretty darn impressive.

    • I never became a spelunker either, but as a child my family visited a lot of caves. Mammoth was the first one I actually remember. I think it's the one that sparked our interest in caves in the first place.

      I don't think I could become a spelunker because I think I'd be too claustrophobic to fit into tight spaces, but Mammoth is...well, mammoth. I would live in it and kick all the tourists out if I could. I'm so selfish that way.

      • I have often heard the fear of claustrophobia expressed. I've never seen someone come out of a cave saying "that was terrible, I was so claustrophobic." I helped with the Fresher's part of the university caving club for about 8 years - that's probably several hundred fresh faces overall.

        If you get underground, claustrophobia won't be a problem. You'll be surprised how using a head lamp changes your view of the darkness.

  • by Burdell ( 228580 ) on Sunday September 26, 2021 @01:41PM (#61834487)

    Plugh?

  • Some entrepreneur could buy the caves and turn them into affordable housing, I mean it's almost complete. The way we are treating the planet we are going to have to start living underground, Imagine the future profits by getting in on the ground floor! (pun intended)
    • There are abandoned coal mines, tapped out gold/silver mines everywhere. None of them were converted to residential villas. A few of them grow mushrooms though.
  • Is 3D LIDAR cave mapping still hard, or are we near to being able to fly a drone or drive a rover through a system, and get an accurate aggregated 3D map quickly?
    If not, why not? Is automatically stitching point clouds together very hard?
    I am asking, because this tech would be so awesome for Lunar and Martian tunnel systems.
    • Are there such things? Tunnels on earth are as far as I know made by volcanism and water, neither of which have existed in large quantities either place for a very long time.

      • Both the Moon and Mars were volcanic ally active for a long time, and there's evidence suggesting that both have lots of lava tubes, probably larger than on Earth. As I recall, under the low lunar gravity stable lava tubes could potentially be miles wide. And much smaller and more stable ones are probably far more plentiful, while being plenty wide enough to build towns in.

        • by nasch ( 598556 )

          That's pretty cool!

        • And much smaller and more stable ones are probably far more plentiful, while being plenty wide enough to build towns in.

          You have more confidence in the stability of cave roofs than I have. But I've probably crawled through more "hanging death" (technical caver's term, do it need an explanation?) than you have. I can tell by the way that you seem to have an immense amount of confidence in the stability of cave roofs.

          And you are volunteering other people to live under this stuff? That's not something I'd ask

          • Yeah, I've stayed away from hanging death. But there's also lots of caves that *aren't* hanging death, and would be potentially suitable for living in.

            And keep in mind that on the Moon, or even Mars, the environments are far different than on Earth. The two biggest factors being far, *far* weaker seismic activity, and virtually no water - two of the biggest factors that degrade the structural integrity geologic formations on Earth. (And of course that also means that many kinds of water-carved cave system

            • I was puffing my fag outside the pub last night, looking at a wall (ashlar corners and rubble straights ; coping stones ) which they'd barriered off because it had started collapsing - probably a consequence of the tree on the other side of it. Thinking of how I''d approach the task of bringing the wall down in a controlled manner so it could be rebuilt (both properties are "listed buildings" - the owners are not allowed to significantly change the external appearance of the building). Every step of the pro
              • They're certainly unlikely to do any major construction using materials from Earth, but lunar resources are plentiful. Keep in mind that we're likely to be on the moon a long time, and the driving force is going to be building an industrial base there to supply raw materials for orbital construction. With oxygen likely being the first major export - it's 80% of the propellant mass for Starship, and lunar regolith is about 45% oxygen by mass. Plus, using Sadoway's electrolytic magma refinery the side-prod

                • You say it yourself (my emphasis):

                  but if you have ready-made cast-stone tunnels of adequate structural integrity

                  Yes, there are some tunnels on both planets. But if they have adequate strength. Where we can see into them, by definition the roof has collapsed - and probably relatively recently.

                  Some schmuck - very likely with at least half his degree studies having covered the same areas as me - is going to have to put his name to a piece of paper saying "this roof is strong enough for people to live under".

                  • Have you considered just how much reinforcement air pressure alone would actually provide?

                    One atmosphere of air pressure equals ten tons per square meter of outward force - under the moon's 16.6% of Earth gravity that's enough to completely support the weight of more than 20 meters of basalt directly above any tunnel, even if it all spontaneously crumbled to sand. Especially for a relatively small tunnel only a few tens of meters across that's way more support than you actually need. And for tunnels very n

                    • Have you considered just how much reinforcement air pressure alone would actually provide?

                      Well, at least one person in this conversation has spent decades dealing with the fact that (this is complex) rocks aren't gas tight. Even for big, complex molecules like methane. The leaked gas tends to make what we call a "gas chimney" above the points of greatest gas pressure differential. Which (we can tell this by the difference in vertical height between the relatively tight bits and the "chimney roots") is a mat

                    • >rocks aren't gas tight
                      Right, which is what the inflatable tube is for. Inflatable habitats seem to be the way to go for the immediate future, and on the surface you need one of those complex multi-layer structures that's capable of providing micro-meteorite puncture protection. In addition to the abrasion and puncture protection that it needs anyway because every grain of sand and dust on the moon is a razor-sharp impact fragment. Spraying a layer of concrete a few inches thick on the walls is going t

                    • This is getting tedious. You seem to think there is a good reason for many people to live on Mars, and I don't.

                      >rocks aren't gas tight [...] Inflatable habitats seem to be the way to go for the immediate future, [...]In addition to the abrasion and puncture protection that it needs anyway because every grain of sand and dust on the moon is a razor-sharp impact fragment.

                      (How do the blockquote and Q tags compare? Never tried that composition before.)

                      Well, we agree on rocks not being gas tight. But you s

                    • Q tags? You mean the >? Far as I know it's just an older way to quote. I just find it more convenient than typing out quote tags for small clips, and prefer small clips because anyone reading it should already have context so a quick reference should be enough to "anchor" my reply.

                      >Why did you introduce this concept? I haven't.
                      I'm assuming near-term, which means no significant industrial base in place. You've got gravel and sand to work with locally - everything else is imported until you've actu

                    • Oh, and I actually DON'T think there's a good reason for people to live on Mars, at least not for any sort of practical reason - I suspect colonization won't happen in any big way until asteroid mining and the associated habitation technologies have matured to the point that really ambitious homesteaders (quite possibly crazy dreamers) can afford to make the attempt.

                      The moon though is a different question entirely - it's essentially a massive asteroid already captured in orbit around Earth, massing 80x mor

                    • Correction - the moon masses 25x more than the entire asteroid belt. Not sure where I got 80.

                    • Q tags? You mean the >? Far as I know it's just an older way to quote. I just find it more convenient than typing out quote tags for small clips, and prefer small clips because anyone reading it should already have context so a quick reference should be enough to "anchor" my reply.

                      Oh, no, I recognise that style perfectly well (I did use USENET back in the day, once I'd had a phone line installed to the house). A few weeks ago I had a spat with some twat here telling me that there was a noticeable (to him

                    • I'm assuming near-term, which means no significant industrial base in place

                      Absolutly, so you use the industrial base that is closest to hand - which would be chewed up asteroids (NE-asteroids, to be more precise) in the orbital vicinity of the Earth-Moon system.

                      You might have a system on the Moon, but even so, that's still down at the bottom of a gravitational hole, relatively little use for going anywhere other than the Moon. The same arguments for not wasting effort on the Moon apply as for Mars, but wi

                    • I actually have quote tags mapped as a WinCompose sequence, and still don't use them. Just too much hassle.

                    • Just to be clear there is basically *nothing* near the Earth-moon system. There's occasionally stuff that zooms past at ridiculous speeds, and there's stuff near the L4/L5 points. But those Lagrange points are about the same distance away as the inner edge of the asteroid belt, with a 16-minute communication lag to Earth. And while it takes minimal energy to reach them once you escape Earth, that's only if you're happy with *huge* shipping delays, far longer than the slowest trip to Mars. Which is maybe

                    • I'm not feeling very well, so this is going to be rather terse.

                      There's occasionally stuff that zooms past at ridiculous speeds,

                      If it's in an Earth crossing orbit, that is equivalent to saying "it comes back frequently". You get multiple bites at the cherry in relatively short order.

                      and there's stuff near the L4/L5 points

                      There is? I know a number of surveys have been run looking for "Earth Trojans", but with negative results. You may have heard differently, but I'd like to know where. The basic problem is t

                    • Sorry to hear that, hope you feel better soon.

                      Goodness, this is getting long. I'm think I'm going to try to pare this down to some high points.
                      >If it's in an Earth crossing orbit, that is equivalent to saying "it comes back frequently".

                      Depends what you mean by frequent. Their orbit has a different period that ours, most of the time when it crosses Earth's orbit, Earth will be nowhere nearby, it can be many years before the next pass anywhere close. Plus, to actually match speed with it, you've got to d

                    • Some more bits

                      >You're going to have to make using the resources available not "late-industrialisation" but the core of industrialisation.
                      Absolutely. My point is plastic is NOT a local resource on the moon, which is very carbon-poor. Even on Mars it's likely to take a whole lot of industrial development before they're able to make plastics in any quantity. An industrial-scale plastic synthesis plant is not a trivial thing to build, and likely demands a whole lot of supporting industry to already be in p

      • Yes, both have lava tubes and other caves. I don't quite understand why we haven't explored them yet, at all. They mght be perfect for long term stays, because one would be well protected from radiations, and maybe from extreme temperature fluctuations.
        https://en.wikipedia.org/wiki/... [wikipedia.org]
        https://en.wikipedia.org/wiki/... [wikipedia.org]
        • by nasch ( 598556 )

          Nice, thanks.

        • I don't quite understand why we haven't explored them yet, at all.

          Because (this is complex) you can't see through rock.

          OK - caveat : you can see through 30 micron slices. 100 micron in some rocks, but no so many of them, Up to a few centimetres if you've got a high power X-ray machine.

    • by imidan ( 559239 )
      Terrestrial lidar works great in such an environment, and the points clouds are not hard to combine. I suspect many of the challenges are related to the size of the vehicle. You need a big enough battery to move the vehicle and operate the lidar (and likely cameras). A flying vehicle has to be pretty large to lift that weight. A driving vehicle needs to be able to handle very rugged terrain. It's common to find lengths of cave that are under water, so you need to account for that. So you need a nimble, all-
    • Cave wreck electronics.

      Companies that manufacture equipment for caving use field expedient tests such as throwing the test item out of a car at 100mph to see if the test item is fit to go into an actual cave for proper testing. Oddly, they don't get a lot of delicate equipment sent for testing.

      I have helped with doing a Lidar survey in a cave - 1999,I think it was. That was a cave where we'd rigged up a 100m Bosun's Chair arrangement powered by a small diesel engine (with manpower backup) for lowering mem

  • Lol what???
  • by Altus ( 1034 ) on Monday September 27, 2021 @09:17AM (#61837327) Homepage

    These researchers had better be careful, or they may be eaten by a grue.

Keep up the good work! But please don't ask me to help.

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