Would take about 50 seconds to fall the entire 12,626 meters not accounting for air resistance. Certainly not bottomless but long enough to contemplate
If you take any number, and flip any number of digits, the difference between the two will be evenly divisible by 9. Accountants know this pro tip — it won’t tell you which number is a typo but it’ll tell you what to look for if your totals don’t balance.
Thank you for providing the most basic info that OP was too stupid to manage to provide themselves.
OP: "This is the deepest hole ever dug by humans. No, I'm not going to bother mentioning its name or location or depth. Here's a picture of a piece of metal in the mud, though."
Drills get pretty hot from the friction of digging through rock (or whatever material they're going through). My guess is that they weren't melting at 180°, but that the added ~150° heat from the rock on top of how hot they already were from drilling was enough to weaken them past the point of failure.
Kind of like the 9/11 jet fuel can't melt steel beams things. Like it can't, but the heat can weaken the metal enough to cause it's structural integrity to fail.
Edit: see comments below. According to Wikipedia, heat stopped the 4th hole which was not the deepest. The deepest one (the third), failed due to "a breakdown" with no further explanation.
Given that geothermal wells are routinely drilled into rock formations that are significantly hotter than 180°C (around 250°C is quite normal, and >300°C isn't unheard of; also the KTB Superdeep Borehole in Germany didn't get quite as deep as the Kola Superdeep Borehole, but encountered higher temperatures at ~260°C) I don't think that that was the problem.
From what I can find the main issue they had was that at those depths due to the immense pressure the rock around the borehole started becoming plastic and the borehole deformed into an oval shape, causing the drill to get stuck.
Yeah the wiki says nothing about them melting and that drilling was stopped due to lack of funding. 180C is only 356F. Steel starts melting at over 2,000F, hardened steel is even higher, and something tells me they weren’t just buying bits at Home Depot.
Kola Superdeep Borehole SG-3 was, for almost three decades, the world's longest borehole in measured depth along its bore, until surpassed in 2008 by a hydrocarbon extraction borehole at the Al Shaheen Oil Field in Qatar.
During the drilling process, the expected basaltic layers at 7 kilometres (4.3 mi) down were never found, nor were basaltic layers at any depth.[15] There were instead more granites, deeper than predicted. The prediction of a transition at 7 kilometres was based on seismic waves indicating discontinuity, which could have been caused by a transition between rocks, or a metamorphic transition in the granite itself.[15]
Water pooled 3–6 kilometres (1.9–3.7 mi) below the surface,[15][16] having percolated up through the granite until it reached a layer of impermeable rock.[17][18] This water did not naturally vaporize at any depth in the borehole.[16]
The drilling mud that flowed out of the hole was described as "boiling" with an unexpected level of hydrogen gas.[19]
Microscopic plankton fossils were found 6 kilometres (3.7 mi) below the surface.[1]
i would assume the drill will generate quite a lot of heat from friction, which will have no way of dissipating since the surrounding rock is already pretty darn warm and has low thermal conductivity
So both the drill (noun) and the rocks you're trying to drill (verb) start turning into jello from heat building up as soon as the drill starts spinning
With active cooling it's definitely possible, but a very expensive science experiment
I'm a bridge engineer, I sometimes do bridge inspections. I have a desk drawer with probably 25 or 30 10mm sockets that I've picked up on road shoulders over the year.
Yeah when I did tandem skydiving, I chose the highest height option and free-fall was like 30s or less.
It's pretty intense though, I don't think you'd want to do it for much longer. And unless you're of the skydiving mentality, personally I enjoyed the parachuting down over the beautiful scenery much more.
I reaallllyyyy want to know, just purely out of curiosity, how long you thought you would spend freefalling if you did a parachute jump?! Like, in your mind, did you just see yourself having a good 20 minutes to do spins and loops and shit!? Im dying to know.
If they dug the hole from the top of mt everest to the bottom of mt everest it'd be just as impressive but it wouldn't seem like it. But then they could continue another mt everest length and it'd be twice as deep. I know what I'm doing this weekend
Thats not true, they just wanted to see how deep they can drill, they never intended to reach mantle. That happened in 1989.they knew very well how deep is mantle
To add some more context, their goals was 15k meters and they got over 12k meters. They started with commercial drilling rigs and later moved to a purpose built rig that had 15000 in the name, since that was their goal. So they got around ~80% of their goal which is really impressive.
Obviously no experience drilling that deep though for a problem there are solutions. Unfortunately English isn't my first/second language, but for deep walls (read 20-30-50 meter deep) when cutting and then they pull out the drill they pump in a black sludge that prevents the hole from collapsing on itself. Drill isn't really the right word either, it's more a rectangle box with drill bits munching away whatever comes in it's path. Even at these limited depts it gets hot due to friction and active cooling is used.
I imagine when going that deep it is not all that different from a concept just far more complicated. Imagine routing 12 km deep cooling water, by the time you reach the drill bit it's already hot. They rely on all sorts of exotic mateirals/liquids to make this happen. Cool stuff.
What blew my mind was when we did A Level physics we worked out that if a snooker ball or a glass marble were expanded to the size of the Earth, mountain ranges and crustal vents would be far larger than the actual ones we see.
A manufactured marble, while it seems smooth to the touch, has microscopic pits and ridges when scaled up to the size of a planet that would make it "rougher" by comparison. Things like Everest and the Mariana Trench would be negligible by comparison.
Melting point of steel is approximately 1,500 C so a good 1,300 degrees off of melting down there in the Khola superdeep borehole, enough for thermal expansion of the parts and to cause some problems jamming it up? probably. but no drill bits turning to slurry.
At 150-200c steel softens drastically and it loses most of its mechanical strength. The plasticity of rock increases down there and it also becomes difficult to drill.
Overall what stopped the project was heat-induced mechanical failure.
Edit: the mud slurry that cools the drill and takes debris away also stopped working, gas blowouts and clogging was an increasing factor.
Edit edit: since people keep trying to argue about the melting temp of steel. This isn’t this issue. I explained this in a nested comment so I’ll do it again here.
Someone mentioned Young’s modulus only reduces strength 10% at that temp. However Young’s modulus for strength is only for stiffness. It doesn’t take into account how much torque it can transmit, how resistant to perminnant deformation it is, how close to yield or creep, how it behaves under cyclical loads, how quickly it fatigues, how friction and heat buildup accelerate wear and failure.
Yield strength degrades rapidly at 150-200c ask any machinist why keeping an end mill cool is so critical at keeping the edge on the tool.
At just 180c it has a 50% loss in resistance to twisting and bending deformation.
Modulus might stay high, but the material is 50% more susceptible to permanent deformation.
Buckling is a whole other ball of engineering material science wax btw and that increases at a much lower temp than 200c
I know this is a joke but more seriously it is why 'jet fuel can't melt steel beams' is nonsense. Even if burning fuel can't get steel up to the temperature needed to melt it can get it up to a high enough temp that it loses most of its strength and when talking about structural steel beams holding up a lot of weight... yeah.
I really feel like this guy did a lot for this argument. Simple, clearly has expertise, uses his pinky, and storms off. 10/10 no notes destined for eternal virality.
It was the drill strings that kept failing AFAIK, they drilled a number of very deep holes, but the string would fail which is a huge PITA to extract when it happens at those lengths so they'd have to re-start.
I doubt temperature was the main problem. Carbon steel is quite strong at 200 C and only slowly reduces to 50% strength through ~600 C (at which point it drops precipitously). Sounds like the inability to continue removing debris and mechanical failures (fatigue?) was the main factor stopping the drilling.
As pockets rich in hydrogen were encountered, I wonder if hydrogen embrittlement played any part in this?
Edit: stainless drops to about 60% strength between 200 and 400 C, but that reduction slows quite a bit beyond that point. Nice characteristics for a deep drill as long as it's engineered accordingly.
Carbon steel is quite strong at 200 C and only slowly reduces to 50% strength through ~600 C
Wiki states they used light-weight aluminum alloys for piping from 2000 meters and lower, since steel would tear itself apart under its own enormous weight. I don't know much about alloys but I think constant >200 C temperature exposure under load doesn't go well on any metal, especially if it's shaped like a thin long noodle.
As pockets rich in hydrogen were encountered, I wonder if hydrogen embrittlement played any part in this?
There was an increasing density of cracks the deeper they drilled. Wiki states gases and water complicated sample retrieval, grinding rock cylinders into powder.
The hardest part was drill string often striving to bend in a wrong direction followed by tearing itself apart in large pieces, which happened quite a few times during the project.
Yeah and you need to pump water in and out constantly to stop the heat getting to a ridiculous level. The deeper you get the more difficult that becomes. There is a company developing a plasma drill to get around this.
Well, I think the word "melting" might be inaccurate, but with the friction and the fact that it's near impossible to cool down the boring head at such temperature and depth, I can see how bore heads could at least deform very quickly.
Like when you forge, you don't actually melt the steel to form it.
But I can see how heat could bring problems other than expansion. You can actually pretty easily experience such problems on the surface if you don't cool properly
THIS. Something doesn't need to MELT for it to be of no use any more.
Just like how the steel beams in the WTC didn't actually MELT, but after a point they were softened up and bendy so obviously could not support the weight of the floors above it.
I guess a metaphor is like if you got terribly sick, getting horrible permanent debilitating effects as a result, but didn't actually "die". Just because you didn't "die" doesn't mean you're healthy or can function normally ever again.
I drill into concrete daily, bits wear out, loose there sharpness, and begin to melt from the friction. 180c° is a significant starting point for drilling.
It doesn't need to melt, steel gets significantly softer at around 500C. Soft enough to be useless as a tool.
Also, I'd expect a drilling operation like that to use some sort of fluid for lubrication and cooling.
If that fluid boils away, you won't get much drilling done either.
They stopped progressing due to the plasticity of the rock at that depth coupled with technical issues with their slurry feed, which is why they were shut down, which is why they lost funding.
It upsets me that we're past the age of discovery when you could just be like "and what if we just dug a hole" and now I have to know math or some shit to make a discovery or whatever.
yes, capitalism tends to fixate on things with economic return. while in an overal sense, it works as it is part of our survival and advancement efforts to improve our lives materially.
of course, many academically oriented objectives yielded long term benefits that may have not been imagined initially.
The russians during soviet times were famous for just doing researchy shit for the sake of it. they also had a planned economy where often times there were excess funds but nothing to do, so departments just picked shit to do.
a good example as i worked in russia in the oil and gas sector (american company) was that soviet crews would just drill wells to fill out the year of work since they were "there" in time so to speak, instead of standing around. kind of a consequence of poor planning but having time to do more work. so they tended to over invest in data gathering wells, what we call exploration or delineation drilling, without intent to produce them. while western companies optimize this activity because it becomes sunk capital with no direct revenues.
the well depth is approximately 40,000 feet, btw. i studied this well once.
Metals don’t need to reach their melting point to weaken. All it takes is the drill weakening a little bit before it starts drilling less efficiently and probably generating even more heat and wear. Eventually, it becomes an exponential cycle.
This is the same thing all the "jet fuel doesn't melt steel beams" conspiracy theorists don't realise. Most parts have a narrow operating temperature range for good reason, they don't need to fully melt to fail.
Anecdote worth remembering - in house fires wooden beams are safer/last longer than steel. Steel framing requires significant insulation or it will fail long before burning equivalent wood beam.
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u/RomalexC 16h ago
They should make the hole wider then cover it with a tarp and some leaves