Seriously silly questions about caves, some of them with revealing answers
Caves are mysterious places even for those of us who have spent decades in exploring and trying to understand the agents of nature that formed them, and it should be noted that for a large percentage of the world’s population, caves are “terra incognita.” Someone once called the subterranean world “The Eighth Continent,” and it is probably far less familiar to most people than anything they might have learned about Antarctica.
Think of the number of stories, novels, films, and TV shows that are set wholly or partially in caves, often wildly — even hilariously — inaccurately portrayed to those who are knowledgeable about them, but undoubtedly appealing to some aspect of the human subconscious that has a fear of dark, unknown chambers that exist in what is melodramatically — but not inaccurately — described as the “bowels of the earth.”
It is therefore not surprising that visitors to caves often ask questions that, due to the questioners’ innocence, might seem pretty silly to those among us whose avocation — and sometimes vocation — involves the sport and science of caving.
When I first started teaching a high school earth science course to freshmen and a geology and astronomy survey course for seniors, I still harbored a remnant of a notion instilled in me in one of those education courses required of aspiring secondary-school teachers, sometimes taught by a professor who seemingly has never been within a mile of a classroom filled with adolescents (said Mike cynically): that notion being that the only dumb question is the one that is not asked.
But that got kicked out of me after a couple of years when I was finishing up a two-week unit on stars and stellar evolution with my seniors.
We had talked about the birth of the universe — old beyond imagining — and we had analyzed the Hertzsprung-Russell diagram; we had compared the sun with red dwarf stars and massive blue giants, discussed the formation of red giants, neutron stars, and black holes; and we had looked at dozens of slides of open clusters of blazing stars arrayed about a nucleus like swarming bees; spectacular nebulae spangled with gases and dust of every color of the spectrum; spiral galaxies, barred spirals, elliptical galaxies, irregular galaxies, all of them fantastically huge and beautiful beyond belief — and all of them sufficient to make one wonder in the silence of one’s bed at night if those folks who believe in intelligent design might just be on to something.
I was wrapping up our discussion in preparation for a test on the unit the next day when I remarked that, in spite of all the discoveries made by wondrous instruments such as the Hubble Telescope, there were still many things that we do not know about stars.
At that moment, a rather sleepy-looking student who shall remain nameless and who — as I recall — had not shown much more than tentative signs of life during his weeks in my classroom, raised his hand. When I called on him, he asked, “When the astronauts go up in the space shuttle, can they go outside?”
Confused by the seeming irrelevance of the question I replied, “Yes, of course. But what does that have to do with the test tomorrow?”
The look on his face suggested he had hit on something that had evaded all those amateur astronomers like Steven Hawking and Neil DeGrasse Tyson and he said smugly, “Well, next time they go up there, why don’t they just go outside and get a couple of stars, and bring them back down to Earth?”
Needless to say, the reaction of some of the more knowledgeable students in the class was — shall we say — less than charitable toward the student’s question and they showed it, while I tried not to crack a smile at this young man’s total cluelessness and gently explained what he should have known weeks before: Stars are a bit too large and hot to fit into the cargo bay of a space shuttle.
How much of a cave is underground?
Anyone who has ever guided a group of tourists through a commercial cave or taken a group of wet-behind-the-ears novices on their first “wild” cave trip has, of course, heard many, many preposterous inquiries — and it requires the patience of Job not to roll the eyes, sigh like a spouting whale, and say, “That is a seriously silly question.”
Years ago, when I had taken another group of students on a week-long trip to Mammoth Cave, we were on what was called the Historic Tour, and our guide — all decked out in his Park Service uniform and Smokey-the-Bear hat — told the crowd of about a hundred that the only dumb question was the one they didn’t ask.
After a couple of fairly intelligent questions that had to do, as I recall, with the age of the cave and the great size of the passageways, the ranger pointed to an anonymous hand waving above the crowd and said, “Sir?” At which point came the question, “Is all of this cave underground?”
I have made it a point whenever I am taking a tour through a commercial cave to ask the guide — when I can catch him or her out of earshot of the rest of the tourists — what is the silliest question they have ever been asked. As it happens, that question about whether all of the cave is underground is a fairly common one.
If the guide can resist the temptation for sarcasm, he or she might say simply, “All that we know of it is.” A guide once told me he had replied, “All of it except for the gift shop and cafeteria” — and drew not a smile from the questioner who seemed to accept those areas as, indeed, being parts of the cave.
Compendium of questions
And, so what follows is a compendium of questions that either I have been asked or questions I have acquired from commercial cave guides.
— 1. How long did it take the Indians to carve this cave out?
This is also a surprisingly common question asked of cave guides. People who have no understanding of erosion and chemical weathering are bound to be mystified and awed by the great size of some cave passages — Mammoth Cave’s Main Passage has room for a modern jetliner to fly through it.
But caves form because surface water has picked up carbon dioxide from the atmosphere or from decaying plants and becomes mild carbonic acid. When this acid comes in contact with calcium carbonate — the main constituent of limestone and marble — it dissolves it to a solution of calcium bicarbonate, which then washes away.
Given the right conditions and enough time, the process can form out huge cave passages. And as for that silly question: If Native American Indians had carved the cave — what on Earth did they do with all that rock they hauled out?
— 2. How thick are the walls of the cave?
The sedimentary rock from which most caves are dissolved forms in layers, which often cover thousands of square miles. In the Helderberg area, most of our large caves (including commercialized Howe Caverns and Secret Caverns) have formed in one of three types of limestone: the Manlius, the Coeymans, or the Onondaga.
The Manlius limestone is found as far west as Syracuse and as far south as Port Jervis; the Coeymans stretches from New York to Virginia; and the Onondaga stretches as far west as Detroit. Each of these areas consists of thousands of square miles, so trying to figure how thick the walls are would be a monumental task, but a good answer would be, “Really, really thick
— 3. How much of the cave hasn’t been discovered yet?
One would think that the response to this question would be something flippant, such as, “We won’t know until we discover it.” But, in fact, it is sometimes possible to come up with an intelligent answer.
If the known passages in a cave have formed in a geographic region throughout which the same geologic conditions exist, there is a good possibility that many more passages have formed under sections that have not been surveyed. By measuring the length of passages in a set area, one might by inference conclude that a lot more of the cave has not yet been discovered and perhaps even extrapolate a rough estimate of how much.
At Mammoth Cave in Kentucky, for example, the same geologic conditions exist for hundreds of square miles, beneath some of which are over 400 miles of explored cave. But, by extrapolation, geologists have concluded that there could be in excess of one thousand miles of the cave when — or if — Mammoth is ever fully explored.
— 4. Is any of the light down here natural?
Since caves are roofed by solid rock that can be many hundreds of feet thick, with rock walls that can be hundreds of miles thick, and with bedrock floors that may literally stretch to the Mantle of the Earth, it is highly unlikely that any natural light could enter beyond what cavers romantically but accurately call the “Twilight Zone.”
This is the region near a natural entrance to a cave into which dim sunlight may reach, and that may have unusual ecologies, featuring both plants and animals that exist in a world of feeble light and perhaps wildly changing seasonal temperatures.
Sport cavers carry their own lights (a minimum of three is the requirement) and commercial caves have complex and often expensive electrical systems for lighting.
— 5. How many undiscovered entrances to the cave haven’t been found yet?
When asked such a question, cave guides must be tempted to say, “We’ll know when they have been discovered.”
But again, what seems to be a no-brainer actually can have a rational, scientifically based answer. Caves form in regions of limestone or marble bedrock known as “karst.” Karst areas usually are characterized by mainly subterranean drainage of runoff into extensive cave passages, numerous springs, streams that tend to go underground shortly after they get started, and a surface pock-marked with the depressions known as “sinkholes,” which permit surface waters and sometimes human explorers to enter the caves below them.
But sinkholes can become occluded: wholly or partially blocked up by sediments and other natural debris that may effectively cut off everything but water from entering the cave systems.
Scientists known as hydrogeologists who study the effect of local geological conditions on water flow — above as well as below ground — have developed a technique known as “dye tracing” to permit following the flow of water to places humans cannot go. This process involves placing harmless dyes in water that is sinking into the ground and then watching the suspected resurgence points to see if the dye-laced waters emerge, indicating there has been a connection.
My young research assistant Devin Delevan is pictured standing at the brink of a vertical sinkhole near the village of Clarksville, an area known to have extensive cave systems. Though in the photograph the sinkhole is dry, in times of heavy precipitation dye could be added to water, pouring into it and a connection might be determined.
Karst areas often have hundreds of such sinkholes, many of which could be hooked into a cave system through this method, even if a human could not physically enter the cave. Numerous previously “unknown” entrances could thus be identified.
— 6. What happens if there is a fire while we are in there?
This question was actually asked of me some years ago when I was guiding a group of students from a downstate New York college through Clarksville Cave.
One young man took a look at the cave’s tight, intimidating entrance and a vision must have passed through his head of a dozen students madly fleeing from flames and battling each other to get out of the cave. His question elicited a burst of laughter from several of his fellow students who were clearly aware that there was nothing within the cave that would be capable of a conflagration.
I assured him of that fact and his face turned red and I expect his question went the rounds through the dorm that night, much to his embarrassment.
— 7. How much does it cost to air-condition (or heat) this cave?
Since limestone and marble and other kinds of dense rock are good insulators, beyond its Twilight Zone a cave will remain pretty much the same temperature all the year around. Caves generally will assume the average ambient temperature of the area in which it is located, making caves seem cool in summertime and warm in winter — everything being relative to temperatures outside the cave at a given time.
In the Helderberg/Schoharie area, yearly average temperatures are about 50 to 52 degrees Fahrenheit, and that tends to be the temperature of our caves. No artificial cooling or heating is required.
Two truly preposterous queries
There are undoubtedly many more Seriously Silly questions that cave scientists and guides have to deal with, but then there are the ones that are truly preposterous or totally incoherent, and I will end with two of these.
Not long ago, I was touring a commercial cave with a group of students and popped my question to the guide, a young woman college student. She did not hesitate for even a moment. Last year, she told me, she and several other guides had been asked a question that was the talk of their crew for several weeks: People on tours were asking, in all seriousness, “Is this the cave that was moved from New Jersey?”
Understand: The visitors’ portion of this cave is over half a mile in length and in places 60-feet high. How and from where the idea had circulated that it had been moved from another state no one seemed to know, but, not wanting to risk losing her job over a condescending reply, the guide had answered simply, “No, it’s been right here in Schoharie for thousands of years.” The guide reported that no one in her group had even cracked a smile.
At the same cave the year before, I had posed my question to a young man who was majoring in geology at a local college. He told me that some weeks before, while his group was standing on the banks of the cave’s gurgling underground stream, a visitor had asked “Is the water in this stream real? Or is it natural?”
Aware that the man’s question was absolutely serious — but unable to decipher its meaning and unwilling to prolong the issue by asking the man to explain what he meant — the guide replied, “Actually, we have both in the cave.”
The man nodded and seemed satisfied.
And that stunner and the one my student asked me about packing up stars in the space shuttle and bringing them back to Earth have permanently put an end in my mind to the notion that the only dumb question is the one you don’t ask. Professors of education, take note.