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A cave in Romania that was sealed for 5.5M years (bbc.com)
889 points by ForFreedom on May 12, 2016 | hide | past | web | favorite | 161 comments

Some interesting takeaways::

- The cave is called "Movile".

- 3 species of spider, a centipede, 4 species of isopod (the group that includes woodlice), a leech never seen anywhere else in the world, and an unusual-looking insect called a waterscorpion

- Movile's only snail [probably the only snail species] suggested that it has been down there for just over 2 million years.

- Many animals are born without eyes, which would be useless in the dark. Almost all are translucent as they have lost pigment in their skin.

- The cave seems to have no contact with the surface; Chernobyl accident had released lots of radioactive metals, which had found their way into the soils and lakes surrounding Movile Cave. However, a 1996 study found no traces of them inside the cave.

- The ecosystem seems to be supported by chemosynthesis; bacteria oxidise methane, sulphide and ammonia, generating energy and organic matter.

The sad irony is that by opening it and discovered it, we've ruined the entire ecosystem. But by not discovering it we never would have known about it, and it is an educational opportunity lost.

Really cannot win either way. Just have to hope there are other, undiscovered, caves like this around the globe.

Have we? We've definitely changed the ecosystem, but it doesn't sound like things have changed all that much in the 30 years since it was discovered.

I guess it depends how you define "ruined", but it doesn't sound like any species have been lost, or life in there has been interrupted in any significant way.

There are almost certainly thousands, if not tens of thousands, or hundreds of thousands of undiscovered caves exactly like this around the globe. And even that is probably a wild underestimate. The world is a very, very big place, and humans, despite all our activity, have barely scratched the surface of most of it.


I really like this word! Did you coin it just now?

Thanks! To my knowledge, yes; I haven't googled.


See you in Lake Vostok

That lends credence to Journey to the Center of the earth.

Maybe we still have dinosaurs lurking somewhere? Jurassic Park anybody?

They installed an airlock to keep changes to a minimum.

Edit: a double airlock

They also washed their hands before they went inside.

Edit - and wore a hair net

Oh good. They likely wiped their feet too.

Edit - on only one of the three spider species.

I hope they had their white coats properly buttoned.

Hope they didnt bring something outside :D

Nah, just like most of the animals in that cave wouldn't survive outside of it, nothing from outside world would thrive inside of it: the conditions are too different. With low oxygen, and food sources that require extreme specialisation it's hard for any invasive species to take hold.

We have the rest of the Universe that is untouched by human hands As Carl Sagan would say, there are "billions and billions" of stars each with its own solar system. We have a long way to go before contaminating everything. Some people find reasons to be depressed.

I don't think it's SO bad. There's still an opportunity to protect it and learn from it without completely destroying it.

All the more reason to develop better robots for terrestrial exploring.

I agree

> Just have to hope there are other, undiscovered, caves like this around the globe.

But the moment we discover them...

Let sterile robots do the spelunking!

Can they do it in the dark? We still have the Marinas trench! We have to really make an effort to contaminate that!

Is there really such a thing as a sterile robot? Chances are that our probes have carried some microscopic life to Mars already.

The question is, assuming that life survived space travel, can it survive there, let alone thrive?

Also, the people involved in those missions must have known about the possibility of contamination. Do they take no steps against it?


You sound depressed.

The part about "The bacteria's ability to oxidise methane and carbon dioxide is of particular interest." -- which seems to mean "ability to oxidise carbon dioxide" -- can't be right. Maybe the meaning is methane to CO2?

How can you still extract energy from a O=C=O molecule without using something like flourine? On the other hand, how does the CO2 get back into the carbon cycle? Do the organisms use an endothermic process to get the carbon back?

And has the 10% oxygen content been there since the cave was opened? Or was this the first mass extinction? While the water does not reach the cave, is there a way for air to make it through? I would expect no oxygen otherwise.

I also thought it was an error, but Wikipedia says:

12 H2S + 6 CO2 -> C6H12O6 (=carbohydrate) + 6 H2O + 12 S


Yeah, that was a glaring error by the author of the article... However, upon re-reading, I noticed this sentence a few paragraphs above:

> "The bacteria get all of their carbon from just one source, be it methane or carbon dioxide,"

So I'm guessing the author really wanted to say "the bacteria's ability to fix carbon from methane and carbon dioxide is of particular interest".

I'm guessing that the full cycle is the same as the above-ground cycle of photosynthesis (CO2 + H2O + energy => O2 + food) and respiration (O2 + food => CO2 + H2O), except replacing photosynthesis by chemosynthesis.

I think it should be: The bacteria's ability to oxidise stuff into methane and carbon dioxide is of particular interest. (From https://en.wikipedia.org/wiki/Movile_Cave the cave is full of co2 and methane).

Movila (plura: movile) means mound in romanian

>The cave is called "Movile" I don't know if I would call this an interesting takeaway lol, more like just a fact you need to know when talking about this.

"in pitch darkness and temperatures of 25 °C"

Is this supposed to be terrifying? Anyone who woke up at night and walked to the bathroom faced pitch darkness and temperatures of 25 °C!

It is possible the authors were just trying to illustrate the remoteness of the ecosystem, without meaning to evoke emotion.

Regardless, I don't think many city dwellers have ever experienced pitch black.

I don't think anyone has. When it's that dark you get a free light show courtesy of your eyes. It was quite disconcerting the first time it happened to me.

Clearly you've never been in the (real) middle of nowhere at night when it's cloudy. Rural North Dakota, for example.

Stars put out quite a bit of light in remote areas, cloud cover may block ~75% of this, but it's still far from 'pitch black'. One of the stranger things about caving is it just keeps getting darker as you go deeper.

PS: As a kid I used to spend a lot of time walking around in starlight. I only ever really used a flashlight inside. I moved much closer to a city and light pollution is terrible to the point where there is little need to turn lights on in my apartment unless I want to read something.

I think he means the noise you see in the complete absence of light, or Eigengrau.

25 °C for British people is pretty terrifying :p

Google's Irish datacenter does not even need the cooling since it never gets that warm in Ireland and in an unlikely case it did you can just shut down servers for that few hours of unexpected summer.

I'd definitely be in shorts for that searing heat.

You'd be complaining about the heat at that point.

We need to start having conversations about whether the law compels people to go home from work and school at that sort of temperature.

Combine that with damp, low oxygen air, confined space and protective suit with all the equipment you must be wearing, and I'm sure it gets irritating pretty fast.

It adds to claustrophobia if you're descending through a narrow crack in the ground :-)

I was expecting a bit more extreme number myself after the 'alien place' buildup.

I don't know where you live, but I bet it's not Canada.

That whole section of the article seemed pretty silly. Talking about rappelling down a rope, through a tight passage, and through twisty, turny little passages is really just another cave, in that respect.

If you're claustrophobic it might put you off, but if you've done any spelunking, this is nothing at all to write home about.

Unless linked to geothermal structures, most deeply underground caves are much cooler than that, around 10-15°C.

In a deep maze of subsurface caves filled with all kinds of creepy crawling bugs, where you could easily get stranded if your ropes to the surface get cut, then yes.

Yes that's fucking terrifying.

The title is a bit misleading. The cave was discovered in 1986. It's just that this article is a bit more recent.

What's 30 years compared to 5.5M :)

That's because the title was made up by the poster and not the original.

> the title was made up by the poster

And it's a linkbait and should be fixed by the mods.

Also on BBC September last year:


That's the same link

The OP probably saw this posted in the TIL subreddit. This article is 9 months old, posted on reddit 12 hours ago, posted on HN 7 hours ago.

Fewer than 100 people have been allowed inside Movile, a number comparable to those who have been to the Moon.

BBC reporting is really kind of crappy. 12 people walked on the Moon; 22 people orbited the Moon.

12, 22, and the number of people who have been in the cave are all fewer than 100. Same order of magnitude.

Technically 100 and 32 are comparable numbers.

Technically all numbers are comparable.

What about imaginary numbers?

You can still compare them, e.g two numbers could or couldn't be equal. Equality is a form of comparison

wouldn't this make all things comparable?

Except apples and oranges apparently.

You can compare apples and oranges alphabetically.

As far as I can tell, it's not that you can't compare apples and oranges, it's just often misleading.

You don't even have to do that: Just well-order the universe and use the resulting ordering for your less-than operator.

1 != sqrt(-1). That's an example of a comparison between a real number and an imaginary number.

That's a rather narrow definition of comparability. If nothing else said, one would understand the term with regards to the relation of any partially ordered set – not only the one implicitly defined on that page.

I define a non-word "uncomparable" to mean something specific and rather arbitrary, but I do not intend it to be the antonym of the real word "comparable". I'll try to clarify this on the webpage you linked to. - Robert Munafo

Would a tl;dr here be:

Is BB(26) - BB(25) greater than or less than BB(25)?

I am certain it is greater. BB(n) grows super-exponentially.

In fact I would be willing to bet serious money that BB(n+1)/BB(n) is greater than BB(n) if 3 < n.

(This is, of course, assuming that one assumes that BB(n) is well-defined. That is an interesting point of philosophy given the existence of Turing machines which can't be proven to not halt.)

> In fact I would be willing to bet serious money that BB(n+1)/BB(n) is greater than BB(n) if 3 < n.

BB(n) grows faster than any computable function. In order for BB(n+1)/BB(n) > BB(n) to hold, BB(n) merely has to grow faster than a sequence whose new terms are obtained by repeated squaring (like k^2ⁿ). That's computable, indeed primitive recursive, so BB(n) definitely grows dramatically faster than it.


Edit: another way of looking at this is that the Ackermann function grows unbelievably faster than functions that easily satisfy the property you describe, and the Busy Beaver function grows unbelievably faster than the Ackermann function. Somehow putting it this way feels like an understatement, though!

It is unfortunately not that easy. Consider the following function, if n is even then f(n) = BB(n/2), else f(n) = BB(2n). Then f(n) grows faster than any computable function, but still if n is odd, then f(n+1) < f(n).

However you have encapsulated the reason why I would be confident of this result. :-)

Google didn't help me. What's BB(#)?

Busy Beaver

I think people are downvoting you because they're assuming you're not serious. :(

Technically all nouns are comparable under equality.

So are e, π and googol.

33 people: 0.00000045810% of the earth's population

100 people: 0.00000134736% of the earth's population

Seems fairly comparable to me.

Yes, because when humans think of groups of people, we usually think in terms of percentage of Earth's population.

"How many people are coming over for dinner tonight?"

"Oh, not too many, just about 2.8070175e-10%"

"Ahh, so one chicken will do"

It was 29 in 2010. Sounds like it's much smaller than 100.

And it's just a tad bit more expensive to get to the moon than this cave, and by tad, I mean it's probably more expensive than any other activity a single human being has ever done, so I'm not sure why they use this comparison.

And two more went around the moon but never entered orbit.


Do you mean Apollo 13? It had three astronauts on board.

Yes, but Jim Lovell was making his second trip; he had previously orbited the moon as part of the Apollo 8 crew.

Maybe I've missed it, but how exactly do they know it was cut off for 5.5M years?

Good question. I've read a bunch of articles about it (haven't delved into the research papers), and none of what I've read ever mentions that.

That said, I suspect it's based on the location and composition of the cave and it's surroundings.

I would like to know this too! I'm trying to think it must be some radioisotope dating, but I don't see what they would be comparing or sampling. It would also be interesting to do some DNA dating differential method between species.

I find this fascinating! Googling a bit, it seems there is a documentary on the Movile cave: http://www.dailymotion.com/video/x1qpffb_the-secret-underwor...

> Strangely, the worse the air gets the more animals there

> are. It's not at all obvious why that should be, or how

> the animals survive at all.

Mmmm I think it's the opposite: On more animals using the same static air balloons, less Oxygen will be there.

Almost like concentrations of humans

A walk-through of the cave:


It gets more interesting starting on the third video.

Goes to show how resilient life is. Which makes it all the more unlikely that life is all that rare.

Resilience is probably not that closely linked to the probability of arising. Maybe once it exists, it is resilient, but when it is absent, chances of it arising are still very low.

"Given enough time, hydrogen starts to wonder where it came from, and where it is going."

Based on what? The only planet that we've explored extensively (Earth) is teeming with life everywhere we look.

But we didn't exactly choose this planet for our explorations randomly. We explored here because we lived here, and found there is life. Can't really extrapolate from that.

Just a thought. As you yourself say, we know only of one planet with life. However, looks like life only arise once on this planet. If life is so abundant in the Universe, why wouldn't it at least arise several times independently on the planet where the conditions are so great?

It would have to die off before it could arise again. Fortunately with a Hillary Clinton administration looming, we may get to see that scenario play out.

This is like, textbook survivorship bias.

hah... Good point.

Both HN and BBC titles are rather clickbaity. Pity for what turns out to be an interesting article on non-photosynthesis-based food webs, communities, and metabolism.

I believe the protocol here is to not complain about the title without suggesting a better alternative for the mods.

I know. Point is there's not a particularly good option as suggests itself to me.

You too?

Are animals in a cave like this considered endangered species?

Well, they are now that we found them.

But were they endangered before we knew about them?

Their state of endangerment was a superposition of being endangered and not until the cave was opened.

Probably not, because their situation has been stable for 5,5 million years. You wouldn't expect them to go extinct unless something changes (like a major collapse of the cave).

This is fascinating. Life is everywhere. This is real "pitch black", just with smaller monsters.

Perhaps the Andromeda Strain will be found in a cave, not in space...

You might like Peter Watts' Starfish.

Thanks for that, I'll take a look.

What I'm reading is that the cave is like a 5-million year old micro brewing process, and as with many microbrews there are some nightmarish scorpions and spiders and scary creatures associated with the cave's brand. If that allegory is correct, then by exploring that cave we have essentially opened the cork and stuck our finger in, haven't we?

Holy shit my city is #1 on HackerNews.

Those creatures have evolved on their own tangent. Quite interesting to see how different they are compared to the creatures outside of the cave.

On another note an well hidden cave like that would be great for preserving man made historical artefacts.

... and then humans came along and filled it with coke bottles, plastic bags, old car tyres and other rubbish.

So in summary, life, ahh, finds a way.

Cenozoic Park just doesn't have the same ring to it. Especially since all parks are technically Cenozoic Park.

    > became roughly the 29th person to enter

"We don't know for sure how many of his girlfriends Steve has snuck into the cave over the years, and frankly we're afraid to ask."

This article reminded me of Terreria and the caves in it.

Minecraft dungeon discovered!

> Movile's only snail suggested that it has been down there for just over 2 million years

This is a bit misleading. It should say only species of snail, not a single snail that's been alive for 2 million years

We detached this subthread from https://news.ycombinator.com/item?id=11683260 and marked it off-topic.

Of course he's been single for 2 million years... it's not like he could go out and paint the town with the door closed.

Rotifers keep it in their pants for two million years

I don't know, it seems like a valid figure of speech to me. But I would agree that the writing in the article is distractingly amateurish.

You can't trust a snail anyway. They lie... and eat your spinach when you're not looking.

Like comments like this, but just a heads up that dang has ban user who repeatedly post summaries in the comments.

EDIT: Here's a recent comment from dang (the main HN mod) on the topic of summary comments: https://news.ycombinator.com/item?id=11608134

We detached this subthread from https://news.ycombinator.com/item?id=11683260 and marked it off-topic.

I tend to agree with the user who defended summary comments on the basis of the utility of top-comments to decide whether the article is worth reading. If people consider summary comments to be a non-positive addition to HN discussion threads then I would hope this can be resolved by the normal down-vote process rather then through special measures.

Any reason that HN doesn't have a meta and way to visualize show that a submission/comment has meta related content tied to it?

I'm not sure I follow, but the answer is probably that it would complicate things.

Takeaways are the best part of HN comments. It's always interesting for me to see what stood out to other people versus myself. Why are they a cause for banning users? That seems like stifling intellectual discourse to me.

I agree, I enjoy takeaways because it gives me a point of comparison. Also if I suspect I'm not interested enough to check out the actual link, it's helpful to determine if the link is worth checking out after all.

dang's position is that HN threads are about conversation. That's a weird constraint though, and I doubt takeaways reduce conversation in the first place since there's always going to be a difference to one's own internal summary of the post. Perhaps the conversation aspect should be measured empirically, compare threads w/ takeaways vs without ;)

EDIT: I will also say that HN's main draw to me are the comments that are informative. The meta-analysis is super helpful. Takeaways could be considered at the bottom of the range of meta-analysis, so banning people for takeaways might also reduce informative comments.

I think that takeaways do always reduce the quality of conversation. If someone is unwilling to be engaged enough to even glance at the linked article, they probably can't provide meaningful or relevant commentary on it, having read only the synopsis. The amount of effort it takes to RTFA is practically nil.

I've seen entire threads spawn from a clear misinterpretation of the title alone. Encouraging people to put as little effort as possible into understanding a topic can't possibly improve the quality of the discussion around it.

And that doesn't even consider the likelihood that whomever is creating the summary is consciously or subconsciously applying a bias to controversial articles.

Unfortunately, it does seem like a bit of a zero sum game. Providing a summary of the article will prevent people from reading the article, and people would rather engage entirely with the comments than the article itself.

>> Providing a summary of the article will prevent people from reading the article

>> I've seen entire threads spawn from a clear misinterpretation of the title alone

Those who would only read the summary are the same ones who would only read the title when no takeaway is present. Should these people be willing to at least read a summary, I suspect that in the majority of cases the resulting comments are a tad more on point. Barring any serious bias by the author of the summary as you mentioned.

>> If someone is unwilling to be engaged enough to even glance at the linked article, they probably can't provide meaningful or relevant commentary on it

Unfortunately the commentary will come, whether it's based on a title or a summary.

>> The amount of effort it takes to RTFA is practically nil.

I agree... most of the time. Sometimes, articles are far too long for what is being reported. How in the world some authors manage to write 20 pages of drivel to stretch out an article that could be presented in one paragraph is beyond me. If I'm not quite sure whether a certain submission interests me, and the article is extremely lengthy, I appreciate having a summary to look at to decide whether I'm willing to invest 15-45 minutes to RTFA - or whether to close the tab and move on. If even skimming the article becomes too much of a chore, I'd rather just get the important tidbits from a summary and move on - usually without dropping a comment.

Common example: articles on criminals and their court proceedings. I just want the facts pertaining to the case. More often than not, I don't give a rat's ass about the 90% of the article that is dedicated to detailing every moment of the defendant's childhood and the lives of every single family member and acquaintance they've ever had. I'm not interested in a woven tale designed to evoke my sympathies. I really don't care to know their favourite flavour of ice cream. I understand why authors choose to write such articles; namely, to tell the other side of the story and humanize the situation. They often just stretch it out too far for my liking, and a summary saves a lot of time.

Mod experience -

Mods see user behavior patterns inverted - you see comments, they see users who make repeated comments of a certain type.

Good mods eventually curtail some of that behavior for valid but hard to deduce reasons.

I'm guessing that in this case, it's been stopped because user behavior shifts, and people use summaries instead of reading the article.

Edit: it's also generally bad form to have meta discussions, it encourages a form of navel gazing which worsens the signal to noise ratio.

Hm... I didn't realize that. I posted my summary because (1) the article was written in a very long-winded way, (2) the discussion here wasn't that good, and (3) I was trying to expose the (for me) most interesting aspect of the whole ecosystem, chemosynthesis - in hope of generating a bit more of discussion around that!

Your comment was fine. We mostly just don't want predictable patterns. The litmus test is whether it fits with good conversation or not.

It helps that you put "interesting takeaways" rather than tl;dr, because it brings your own opinion into the fold. I don't need to guess whether you've missed anything or not because it doesn't matter. You've stated clearly your points are those you find interesting. Which is much better than simply mechanically spouting a summary like a machine.

That user was applying for funding from HN to start a summarising service. They started dumping summaries in HN threads to advertise the effectiveness of the service.

There's a bit more context than just "dang bans users who tl;dr".

I often only read articles because I thought the summaries/takeaways were interesting... :/


2 of Bushra8's 3 comments have come from 2 different Reddit users, so it would seem.

We've banned that account and another one doing the same thing. If anybody notices more of this, please let us know at hn@ycombinator.com.

Are you kidding ? It sounds amazingly fun. You get to go to a place no human went to, you discover entirely new animals, and you get to do acrobatic stuff in the process, using tech equipment. It's the closest thing to being an astronaut or meeting aliens.

No kidding! I have immense respect for the scientists who are willing (and able!) to go into these places to bring back research and information for the rest of us.

Right, just saw this a minute ago on reddit. It seems like HN is just /r/Futurology, /r/TodayILearned, /r/Programming, and /r/Startups rolled into one.

I'm here for the comments

Meh. I used to think more highly of HN comments, but as they started covering stuff I already knew a fair bit about, I realized the highest voted comments usually only have the appearance of knowledge / wisdom / experience / etc, but without the substance of it.

But without all the toxicity.

That must be were my motivation was hiding since last week...

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