New candidate for the Fermi Paradox

November 17, 2012 8:48 AM

David Brin points to Asteroid belts at just the right place are friendly to life -November 6, 2012 , saying "This combination is calculated to be rare, in perhaps just 4% of solar systems. That rarity offers yet one more new, rather daunting candidate for the Fermi Paradox."
posted by hank (63 comments total)

Plus the rocky planet in the habitable zone has to have a liquid metal core to generate a Van Allen radiation belt to keep the planet from being irradiated (sterilized) by the sun. Only 4 planets in our solar system have one. Mars for example does not (or actually very weak). With at least 3 criteria -- habitable zone, asteroid belt, Van Allen belt -- seems like Earth is going to be hard to beat. Luckily there are a lot of potentials.

Then there is this: First rogue planet discovered "Without ties to any star, rogue planets, (also known as interstellar, free-floating, nomad or orphan planets), literally wander through space." Rogues planets are independent and free, they don't have to worry about asteroid belts or Van Allen belts, but they must be mighty cold out there. There is a proposal to name the planet Palin (jk).
posted by stbalbach at 9:11 AM on November 17, 2012 [6 favorites]

Universe's OTP: Rogue Planet/Solar System
posted by The Whelk at 9:17 AM on November 17, 2012

This is not a rather daunting candidate for the Fermi Paradox, so much as a partial resolution of same. And I propose another: If you look at the way humans interact with wild animals--like whales, wolves, and bears, for example--we are evolving towards leaving them alone in their own space and observing them from a distance. If you extrapolate this pattern a few million years and apply it to alien civilizations, why would we expect to see signs of their existence?
posted by weapons-grade pandemonium at 9:21 AM on November 17, 2012 [4 favorites]

If you look at the way humans interact with wild animals--like whales, wolves, and bears, for example--we are evolving towards leaving them alone in their own space and observing them from a distance.

I get what you're saying, but we've also evolved to a place from which it seems likely that most of the wild animals are going to be extinct pretty soon.

To my mind, the simplest resolution of the Fermi Paradox is still nobody gets out of their own biosphere alive. Maybe with a side of "and most of them don't even build radios first". Intelligent life might well be a disease from which no ecosystem recovers quickly enough to support intelligent life for long, or very often. It sure is looking like ours won't.
posted by brennen at 9:37 AM on November 17, 2012 [10 favorites]

We are actually in the middle of the biggest species die off in earth's history; if there were aliens, we would expect them to come here and kill us (intentionally or otherwise) through pollution and habitat destruction.
posted by stbalbach at 9:37 AM on November 17, 2012 [2 favorites]

We are actually in the middle of the biggest species die off in earth's history

I'd ask for a citation, as the Permian–Triassic extinction event is the largest on record, but how do we know how our current situation plays out?
posted by Blazecock Pileon at 10:03 AM on November 17, 2012 [1 favorite]

There's no paradox. You can't calculate the probability of finding intelligent life when there is only one known example.
posted by bhnyc at 10:08 AM on November 17, 2012 [7 favorites]

Bayesian analysis of the astrobiological implications of life’s early emergence on Earth

The early emergence of life on Earth has been taken as evidence that the probability of abiogenesis is high, if starting from young Earth-like conditions. We revisit this argument quantitatively in a Bayesian statistical framework. By constructing a simple model of the probability of abiogenesis, we calculate a Bayesian estimate of its posterior probability, given the data that life emerged fairly early in Earth’s history and that, billions of years later, curious creatures noted this fact and considered its implications. We find that, given only this very limited empirical information, the choice of Bayesian prior for the abiogenesis probability parameter has a dominant influence on the computed posterior probability.
posted by Blazecock Pileon at 10:11 AM on November 17, 2012 [3 favorites]

Well, the economics of resource extraction don't actually work in interstellar space without either fantasy science or quantum communication (which itself might be fantasy science). So I highly doubt anyone would be coming here to pollute. The Sector 9 refuge scenario is a possibility, though. If our biosphere is as screwed as we think (well, slightly less screwed than we think but screwed none-the-less) we might end up being the refuges.

From what I've learned of human evolution, I tend to think that the Fermi paradox stems from the fact that technological intelligence is just so damn unlikely. Any of a thousand accidents had to go our way for us to even survive to this point. Extinction of the dinosaurs, surviving the Toba catastrophe, not having some rogue asteroid or solar flare or ice age wipe us out. Etc., etc. And what if the only intelligent animals on Earth ended up being creatures with flippers or wings or claws, and not ones with nimble little tree-climbing hands? Not much chance of crafting complex tools then.
posted by cthuljew at 10:13 AM on November 17, 2012 [1 favorite]

"We are actually in the middle of one of the biggest species die off in earth's history"

Holocene extinction: "E.O. Wilson of Harvard calculated that, if the current rate of human disruption of the biosphere continues, one-half of Earth's higher lifeforms will be extinct by 2100."
posted by stbalbach at 10:16 AM on November 17, 2012 [1 favorite]

The universe is really big, so it's unlikely that there's no other intelligent life.

The universe is really big, so it's unlikely that they'll visit us.
posted by daveje at 10:21 AM on November 17, 2012 [1 favorite]

Extinction of the dinosaurs.... Etc., etc. And what if the only intelligent animals on Earth ended up being creatures with flippers or wings or claws, and not ones with nimble little tree-climbing hands? Not much chance of crafting complex tools then.--cthuljew

You should look at dinosaurs like the Troodon, a relatively intelligent dinosaur that looked like it was developing a thumb. Given different climatic/astronomic events, there may have been other paths to intelligent life on Earth.
posted by eye of newt at 10:23 AM on November 17, 2012

Permalink to David Brin's post on the subject, for people reading this thread in the future.
posted by stebulus at 10:25 AM on November 17, 2012

You can't calculate the probability of finding intelligent life when there is only one known example.

Hard to nail down what "intelligence" means, exactly. Self-awareness? In any case, the PNAS paper I linked to provides one quantitative approach that the authors suggest relies greatly on "optimistic" assumptions that go into such a calculation:

Although this question ultimately must be answered empirically, via searches for biomarkers (32) or for signs of extraterrestrial technology (33), the early emergence of life on Earth gives us some information about the probability that abiogenesis will result from early Earth-like conditions.

A Bayesian approach to estimating the probability of abiogenesis clarifies the relative influence of data and of our prior beliefs. Although a best guess of the probability of abiogenesis suggests that life should be common in the Galaxy if early Earth-like conditions are, still, the data are consistent (under plausible priors) with life being extremely rare, as shown in Fig. 2. Thus, a Bayesian enthusiast of extraterrestrial life should be significantly encouraged by the rapid appearance of life on the early Earth but cannot be highly confident on that basis.

Some statisticians don't like Bayesian calculations because they are largely dependent on prior assumptions. We'll need empirical data before taking Brin's speculations on face value. Transient habitability in a belt is one thing, but it's not clear that any one asteroid provides time, let alone energy, for life to flourish. One tweak and that body gets quickly kicked out of the solar system or into the sun or another planet.
posted by Blazecock Pileon at 10:35 AM on November 17, 2012

THIS IS YOUR FRIENDLY ADVISORY:

There is only one Solar system. Our star is named Sol, and its system is the Solar system. Other star systems are not Solar systems, because their stars are not named Sol.

Thank you, carry on.
posted by Arturus at 11:06 AM on November 17, 2012 [2 favorites]

...we are evolving towards leaving them alone in their own space and observing them from a distance. If you extrapolate this pattern a few million years and apply it to alien civilizations, why would we expect to see signs of their existence?

If they were intelligent, sentient and capable of interaction similar to the way humans interact with each other, we would be chatting their ears off. There would be legalize whale-marriage campaigns. It would be completely different. Humans hunger for that sort of thing. Why do we have so many domestic pets? To quote a wise man, "I think I’d be willing to be a house pet to a race of super-intelligent aliens."
posted by jeffamaphone at 11:19 AM on November 17, 2012

FRIENDLY ADVISORY:

You are wrong. Solar System is both the name for our own system, and the nomenclature to describe a star with planets around it. Take your pedantry back to English class and let the people who can deal with ambiguity continue the discussion.
posted by absalom at 11:20 AM on November 17, 2012 [5 favorites]

FRIENDLY ADVISORY:

The word "friendly" does not in fact mean "passive aggressively hostile." This is your final warning before we unleash the hounds.
posted by yoink at 11:30 AM on November 17, 2012 [10 favorites]

FRIENDLY ADVISORY:

The Earth and Alpha Centauri A III cricket teams are playing a friendly at Galactic Stadium. Downtown helocar traffic streams may be affected.

As this is not a zero-gravity match all players will be tested for asteroids.
posted by dhartung at 12:01 PM on November 17, 2012 [8 favorites]

I don't know about this. Seems to rely on a lot of assumptions, and some of them seem pretty shaky.

First of all, the punctuated equilibrium idea is ignoring the million other things that can punctuate an equilibrium. Sure, you don't have asteroid strikes... but you probably still have an Oort cloud, so you have comet strikes. If that's not enough to punctuate the equilibrium enough for evolution to occur, what else is there? Supervolcano eruptions, methane hydrate releases, axial tilt changes, magnetic field reversals, large solar flares, nearby supernova explosions, gamma-ray bursts, and interstellar dust clouds. And that's still ignoring all the completely ecological factors that can result in major changes to equilibrium. So punctuated equilibrium hardly depends on asteroid strikes.

As far as the water and carbon go, there are other ways to get it. Comet impacts, for one. So a system with no asteroid belt but a larger Oort cloud might do ok. Also, we don't know how much of the Earth's volatiles were lost in the impact that formed the moon. And there's also the possibility of an Earth-like planet that forms further out and spirals inward a little bit later. So I wouldn't write off Earth-like planets in systems that don't have asteroid belts.
posted by Mitrovarr at 12:01 PM on November 17, 2012

[Substituted direct link to the Brin post for general link to his website; thanks Stebulus.]
posted by LobsterMitten at 12:04 PM on November 17, 2012 [1 favorite]

This is less about the Fermi Paradox than the Rare Earth Hypothesis, but they are related.

You should look at dinosaurs like the Troodon, a relatively intelligent dinosaur that looked like it was developing a thumb. Given different climatic/astronomic events, there may have been other paths to intelligent life on Earth.

In our time, civilization and high technology developed in temperate climates where it could make a dramatic improvement in range and standard of living but conditions were still stable enough to permit development. Civilization didn't develop in the tropics because in the tropics, you don't need it.

In the time of the dinosaurs nearly every acre of dry land on Earth was tropical. There was only one exception -- at the current latitude of the US and Europe, the most likely temperate continent of what is now Antarctica.

There might be the remains of an entire civilization down there under the ice. They might even have achieved space flight; there are obvious reasons why they might have avoided those parts of the world ruled by monsters. I particularly favor the idea when I'm in a SFnal mood that the asteroid strike was an attempt at asteroid mining which went horribly wrong...
posted by localroger at 12:16 PM on November 17, 2012 [7 favorites]

Blazecock Pileon: Transient habitability in a belt is one thing, but it's not clear that any one asteroid provides time, let alone energy, for life to flourish.

The headline is misleading; the actual finding is made clearer in the text:

They suggest that the size and location of an asteroid belt [...] may determine whether complex life will evolve on an Earth-like planet.

It's not about life in the asteroid belt.
posted by stebulus at 12:21 PM on November 17, 2012

Mitrovarr: the punctuated equilibrium idea is ignoring the million other things that can punctuate an equilibrium.

I suspect that remark in the article rests on a misunderstanding of the theory of punctuated equilibrium. As far as I know, there's no connection to catastrophic events like asteroid strikes. (But my understanding of the theory is entirely from reading Gould's nontechnical books over ten years ago, so it's certainly possible that I'm the clueless one here.)
posted by stebulus at 12:28 PM on November 17, 2012

You can't calculate the probability of finding intelligent life when there is only one known example.

Sure you can. If you have some knowledge of how something came about--the requisite environmental conditions, etc., you can look for other environments that would support the existence of similar things. If someone served you a food that you had never seen or tasted before, would you automatically infer that it was unique? Instead, you might study it, investigate the conditions necessary for its growth, etc., and see if other such enivironments existed. You're going to make some errors, but as Fermi himself postulated, the errors of approximation tend to cancel one another, as when estimating a restaurant bill. When the first atomic bomb was detonated in New Mexico, Fermi tore up a sheet of paper and threw it into the wind from the shock wave. He then estimated the force of the blast from the distance the wind took the paper scraps. Days later, when all the mathematial results were in, Fermi's estimation of the number of megatons was almost bang on.
posted by weapons-grade pandemonium at 12:57 PM on November 17, 2012 [1 favorite]

Civilization didn't develop in the tropics because in the tropics, you don't need it.

Well...
posted by cthuljew at 1:07 PM on November 17, 2012

Solar System – A group of celestial bodies comprising the Sun and the large number of bodies that are bound gravitationally to the Sun and revolve in approximately elliptical orbits around it…—Collins Dictionary of Astronomy, p. 382

Planetary system – … A system of planets and other bodies, such as comets and meteroids, that orbits a star. The Sun and its planetary system together comprise the solar system.—Collins, p. 314

However, a great many people, including apparently David Brin, make this mistake.
posted by ob1quixote at 1:10 PM on November 17, 2012 [1 favorite]

But look at the bright side: If enough people *could care less*, it will become correct!!1!
posted by weapons-grade pandemonium at 1:15 PM on November 17, 2012

Blazecock Pileon- that Bayesian analysis is about the probability of life forming. There's a whole lot of improbable steps before you get a life form that builds rocket ships. And we don't have probabiity values for any of these steps.
posted by bhnyc at 1:22 PM on November 17, 2012

When the first atomic bomb was detonated in New Mexico, Fermi tore up a sheet of paper and threw it into the wind from the shock wave. He then estimated the force of the blast from the distance the wind took the paper scraps. Days later, when all the mathematial results were in, Fermi's estimation of the number of megatons was almost bang on.

For those who, like me, had never heard this story before: My Observations During the Explosion at Trinity on July 16, 1945 [text], Enrico Fermi; and an image of the document, on the Los Alamos lab's Flickr account. He says he estimated 10 kilotons. Groves' report on the test says 15 to 20, conservatively. The Wikipedia article is not completely consistent, but cites offline sources for 18.
posted by stebulus at 1:36 PM on November 17, 2012 [4 favorites]

> "Civilization didn't develop in the tropics because in the tropics, you don't need it ..."

Which is surely why human civilization began in the Great Rift Valley of East Africa? Then it reached its next major development stage in the Middle East -- followed by Southeast Asia, North Africa, and Southern Europe. It got its next jump in the Indus Valley of the Indian subcontinent. At that point it started spreading to the temperate climates, sure, and 4,000 years after that an interesting but very likely anomalous historical blip put some countries with temperate climates at the forefront of technological innovation for a while.

Civilization in the Americas also started in the tropics, by the way.

I'm finding your hypothesis dubious.
posted by kyrademon at 1:56 PM on November 17, 2012 [6 favorites]

OK, let's say instead of civilization high technology. Because yeah you might build some cool mounds and stone buildings if you have food production 12 months of the year, but you're unlikely to put much effort into transportation and processing unless you've got gaps to cover. Sure, the Aztecs had a complex civilization, but they didn't even use the wheel, and the ancient Greeks who discovered the steam engine considered it a toy.
posted by localroger at 2:09 PM on November 17, 2012

One of the things that predisposes me towards a Rare Earth hypothesis (i.e., conditions favouring complex, intelligent life evolving) is that we have several unusual factors: not merely the asteroid belt being just so, not merely a liquid metal core providing Van Allen Belts, but also a highly unusual moon, formed early in the Earth's history by a collision with a body big enough and hitting at just the right angle to cause the formation of our proportionately outsized moon. Our moon stabilizes our axial tilt and makes much longer term climate stability over large regions of the planet's surface possible.

I often wonder if Frank Drake included these factors in his famous equation. AFAIK, at least the moon part wasn't included.
posted by Philofacts at 2:13 PM on November 17, 2012

Our moon stabilizes our axial tilt

Some time in the past couple years I saw a talk about the chaotic behaviour of the solar system; the speaker remarked that the large moon also stabilizes Earth's orbit. It was just an quick aside, but I think he was saying that the Earth-moon system can absorb perturbations that would change the orbit of a single body.
posted by stebulus at 2:19 PM on November 17, 2012 [1 favorite]

Pick a spot for the goalposts and leave them there. Two possibly defining characteristics for civilization (as opposed to sophisticated adaptations like beavers with their dams) are 1) prediction and planning: do they have calendars and are they able to constructively order their activities based on predictions which can be transmitted as abstract knowledge? 2) extracting work from nonliving systems: water wheels, windmills, etc. I'm pretty certain you don't have a civilization without the first. The second is a hugely significant technological marker but I don't know if it's definitive.
posted by George_Spiggott at 2:20 PM on November 17, 2012

The unlikelihood of the Moon and all the things it provides to life advancement seems to be the biggest tripping point to me for intelligent life elsewhere now that we seem to be finding Goldilocks planets everywhere. The mind boggles at how rare it must be though maybe there are other paths that aren't dependent on a moon like body.

I was talking about this last week with a friend and his thing is the unlikelihood of just the right amount of water. Twice as much water and *Poof* no land. Half as much water and the Earth becomes a much less habitable place.
posted by Mitheral at 2:23 PM on November 17, 2012 [1 favorite]

You could just as easily argue that a high tech civilization would never have bootstrapped itself without the tropics.
posted by brennen at 2:26 PM on November 17, 2012

The last sentence of my original post suggested spacefaring dinosaurs. Name the technological advances which led to space travel (even early ones like the invention and development of chemistry and the perfection of the steam engine) which occurred south of the 30th parallel.

I'll be impressed if you can even come up with one.

That's where I meant to put the goalposts. Sorry if you thought they were down the field.

The theory as I originally read it came from a Soviet climatologist in the 1970's whose name I have no chance whatsoever of recalling, but I was impressed by the theory that the development of high technology required a climate that was just right, challenging enough to reward innovation without being so challenging as to make it impossible.

Yes, humans spent thousands of years making detailed records of the movements of the little lights in the sky, but it's only because of the recent cascade of innovations that we know what those little lights really are, we've sent machines to send back close up pictures of some of them, we know the true scale of the universe, and it's even possible to have a discussion like this one.
posted by localroger at 2:27 PM on November 17, 2012

Civilization first emerged in a Mediterranean/semi-arid climate on October 29, 1969.
posted by justsomebodythatyouusedtoknow at 2:28 PM on November 17, 2012 [3 favorites]

If you have enjoyed this thread, I commend to you the David Brin (yes, him) / Gregory Benford novel Heart of the Comet, which touches on a remarkable number of these subjects, including, strangely enough, the role of our low-latitude cultures in a spacefaring civilization. Though not perhaps in quite the same way.
posted by George_Spiggott at 3:00 PM on November 17, 2012

The ARPANET reference was intended both as a joke about moving goalposts and a way of pointing out that climate is often largely irrelevant to technological developments.

Now that you've given the 30th parallel as a criterion we can get somewhere. The first accurate measurement of the size of the earth surely counts for something on the road to spaceflight, and that measurement technique could only be performed in the tropics. If you're willing to stretch to the 31st parallel you'd include Alexandria and Euclid's geometry. Quite a lot of ancient and Arabic science, actually. Most of India also falls within that range.

Are you familiar with Jared Diamond's "Guns Germs and Steel" argument about technological development? He did think that climate mattered, but primarily for reasons of technological diffusion. East-West technological spread is easier than North-South because the climate is similar and continuous. Take agriculture. Everybody from Spain to Japan can grow wheat, but Incan crops which might have been useful to the Aztecs never get there because they won't grow in Central America. All of Eurasia ends up technologically cross-fertilizing and advancing quickly while civilizations elsewhere are left to slog along at their own pace in isolation.
posted by justsomebodythatyouusedtoknow at 3:13 PM on November 17, 2012

justsomebody: nice catch on measuring the size of the Earth. They were able to do that because the Sun was directly overhead at a certain location, which definitely favors closeness to the equator.

Too bad they thought their steam engine was just a toy and all that wonderful insight was lost for thousands of years.

Of course there's a similar argument about space travel, since reaching Earth orbit is easier from closer to the equator. Now that we have the transportation technology such things aren't as important, which is why the transportation tech was developed in the first place.
posted by localroger at 3:46 PM on November 17, 2012 [1 favorite]

Sure, the Aztecs had a complex civilization, but they didn't even use the wheel

Oh yes they certainly did.

Until all that unexplored stuff listed in 1491 gets dug up (wooden wheels decay), transportation's an open question. Remember Antikythera.
posted by Twang at 4:10 PM on November 17, 2012

The first accurate measurement of the size of the earth surely counts for something on the road to spaceflight, and that measurement technique could only be performed in the tropics

Why could it only be done in the tropics? All it needs is a simultaneous measurement in two places at the same longitude, no?
posted by stebulus at 4:17 PM on November 17, 2012

It just struck me that the moon, in the form of tides, probably had a lot to do with life moving from the sea to land, and that on a planet without strong tides, animal life might never get onto land. I'm sure I'm not the first to think of this, but there it is.
posted by cthuljew at 4:24 PM on November 17, 2012 [2 favorites]

Does a planet not inclined to the solar plane have seasons? If you don't have seasons, your planet looks a lot different.
posted by maxwelton at 4:36 PM on November 17, 2012

Does a planet not inclined to the solar plane have seasons?

No,and yes that makes a difference, but if your planet has a liquid core it's not going to stay that way. Liquid core planets wobble, and the danger is that they can wobble into the kind of attitude Uranus has, with the axis of rotation nearly even with the ecliptic. You want seasons?

That's what the Moon is for; it keeps the Earth's tilt remarkably constant. You need the liquid core because it generates the magnetic field, the importance of which isn't shielding you on the surface from direct radiation exposure -- that's minor -- but keeping the solar wind from eating the atmosphere away over the aeons. That's why Mars, which we now know thanks to Curiosity once had flowing liquid water, has so little atmosphere today.
posted by localroger at 4:51 PM on November 17, 2012

Twang, the second sentence of your first link reads:

The Aztecs used wheels in children’s toys (such as small wheeled dogs made of pottery or occasionally obsidian) yet never considered using wheels for transport technology!

As I've mentioned a couple of times the Greeks had steam engines too. Toys don't count. Toys don't encourage the improvements in precision and engineering that made those concepts scale into rockets, satellites, and telescopes that can detect planets of other stars.
posted by localroger at 4:55 PM on November 17, 2012

Diamond addresses Aztec wheels. There was nothing to pull wheeled carts. Llamas aren't big enough, and there are no other options in central America. Much easier to just have dudes carry stuff.
posted by cthuljew at 5:01 PM on November 17, 2012

Much easier to just have dudes carry stuff.

I will remember this at work next time I'm tempted to go looking for a hand truck to move a heavy box. Or maybe I won't.

And before you mention rolling surfaces, even the Romans built roads.
posted by localroger at 5:26 PM on November 17, 2012

Why could it only be done in the tropics? All it needs is a simultaneous measurement in two places at the same longitude, no?

Taking one measurement at the tropic of Cancer made it possible for a single scientist to do the simultaneous measurements without leaving his back porch in Alexandria. The trick was that Eratosthenes knew that there was a deep well in the city of Swenet where light reached the bottom (falling vertically) on only one day of the year, summer solstice. Accurate Egyptian surveying gave him the distance from Alexandria to Swenet and from there it's just trigonometry.

even the Romans built roads

Even Silicon Valley can build computers. Even the French can make wine. The Romans built roads that are still here. Americans build temporary road-like structures out of asphalt that can't last a few decades without resurfacing.
posted by justsomebodythatyouusedtoknow at 5:37 PM on November 17, 2012 [1 favorite]

and from there it's just trigonometry.

I understand the method. The only element that depends on the latitude is the use of the well, and it's not an essential feature of the method in any reasonable sense.
posted by stebulus at 6:11 PM on November 17, 2012

even the Romans built roads

Even Silicon Valley can build computers.

Does this have a point? Roads are low tech. Well, I guess the Romans did use wheeled vehicles, but that's kind of a chicken and egg thing. The meso-Americans missed the whole idea.

The only element that depends on the latitude is the use of the well, and it's not an essential feature of the method

The well is very helpful if you don't have very precise measuring instruments. Instead of two crude angular measurements there was only one crude angular measurement. Also, the idea of doing the measurement at all came from the fact that the Sun illuminated the bottom of the well at the Solstice, whereas it did not at the other known location. This was a discrepancy worth pursuing.
posted by localroger at 7:19 PM on November 17, 2012 [1 favorite]

> "Name the technological advances which led to space travel (even early ones like the invention and development of chemistry and the perfection of the steam engine) which occurred south of the 30th parallel. I'll be impressed if you can even come up with one."

Well ... I'll give it a shot. Looking JUST at the history of rocketry:

9th century: Gunpowder developed by Chinese alchemists. Precise parallel unknown, could be above or below 30.

9th to 13th century: Continued development in China, up to internal combustion rocket propulsion. Precise parallel unknown, could be above or below 30. Earliest reported military use was below 30th parallel (siege of Yuzhang). Later military use occurred both above and below 30th parallel.

13th century: Mongols spread rocketry into Russia, Europe, and elsewhere. Roger Bacon develops improved rocket range (above 30th parallel). Korea develops Hwacha rocket launcher (above 30th parallel). Hasan al-Rammah increases explosive power and develops first torpedo (probably right around the 30th parallel).

14th to 17th century: Continued development in Europe, up to multi-stage rockets, batteries of rockets, and rockets with delta wing stabilizers (above 30th parallel).

18th century: Iron-cased and metal-cylinder rocket artillery, enabling higher thrust and longer range, developed in Mysore (below 30th parallel).

19th century: Inspired by Mysoran rockets, British (Congreve, Hale) develop solid fuel rockets and vectored thrust. Russians (Zasyadko) create launching platforms (both above 30th parallel).

First half of 20th century: Modern rocketry developed in U.S. (Goddard), Germany, Russia (all above 30th parallel).

Second half of 20th century: Cold war drives rocket research in U.S. and Russia (above 30th parallel), but significant research begins worldwide (both above 30th parallel, such as in Japan, and below 30th parallel, such as in northern Australia.)

Analysis -

Is there at least one technological advance in rocketry which led to space travel that occurred below the 30th parallel? Definitely. Mysoran work in iron-cased and metal-cylinder rocket artillery is universally acknowledged to be one of the most significant developments in rocketry.

Are there more than one technological advances in rocketry which led to space travel that occurred below the 30th parallel? Possibly. Some of the work from the 9th to 13th century could have, but it's difficult to say. It should possibly be noted that the earliest military use was in Southern China, below the 30th parallel.

Did the bulk of more recent advances leading to modern rocketry occur above the 30th parallel? Absolutely. From the 14th through the 20th centuries, most work in rocketry occured in Europe, Russia, and North America.

Could this be because the nontropical climates are "challenging enough to reward innovation without being so challenging as to make it impossible"? It seems unlikely. Most rocketry innovation was pushed by military goals, which would have been rewarded in all climates where there was battle - which was pretty much all of them. Most of the location of the later development seems to have been the result of historical and geographical accident (e.g., the location of the spread of the Mongol conquests; the collapse of the Caliphate in North Africa and the Near East eroding technological development in that area shortly before the European Renaissance.)

Conclusion: The hypothesis still seems extremely dubious, at least to me.
posted by kyrademon at 7:35 PM on November 17, 2012 [4 favorites]

I'd say the point is that saying "even the Romans", as if they were also-rans, is a distortion, a belittling of their considerable skill in building roads. They dug them several feet, sometimes yards, deep and then built up a multi-layered construction that resisted settling, erosion, and all the other ills that befall roads. They wanted to make sure their chariots and horses could get around their empire at reliable speeds. This is why some of their roads are still around. In contrast, we mostly lay a relatively thin veneer of concrete topped with asphalt (and many roads seem only to be a layer of asphalt atop a packed and rolled dirt base.) Low-tech the Romans certainly were, but quality lasts at any level. (Living in Québec, the pothole capital of North America, I can only wish we had a few Roman roads.)
posted by Philofacts at 7:39 PM on November 17, 2012 [1 favorite]

Yeah, it's weird crossing the border into Quebec from Northern New England. Almost everything looks better and a tad more advanced—clearer and more frequent signage, superior rest stop facilities, the occasional wind farm—but the roads themselves look like they're from a developing nation.

Anyways, I just wanted to add on to the list of tropical civilizations whoever constructed the rice terraces of the Philippines beginning circa 300 BCE or earlier, which evidence superior hydraulic engineering technology to the rest of the world of the same era.
posted by XMLicious at 8:36 PM on November 17, 2012

cthuljew writes "Diamond addresses Aztec wheels. There was nothing to pull wheeled carts. Llamas aren't big enough, and there are no other options in central America. Much easier to just have dudes carry stuff."

Terrain was also a factor.

One of things that is useful though even on hilly terrain and despite a lack of draft animals is the wheel barrow. It doubles or triples the amount of mass and volume you can move around. Undoubtedly one of those obvious inventions in hindsight that as far as I know never pops up in the Pre-Columbus Americas.
posted by Mitheral at 10:49 PM on November 17, 2012

I think it's important to point out that the goalposts localroger has set, whether moved or unmoved, are kind of weird. Arbitrarily declaring that only the technological developments in the 0.2% of most recent human history "count" is very strange and doesn't make a lot of sense even when considered through the lens of the "temperate climate" idea. Casually dismissing all technology until that point as "some cool mounds and stone buildings" is utterly ridiculous.

It smacks a little of the argument I read somewhere on Metafilter many years ago where someone was arguing that Islam by its very nature stifles scientific progress and no such progress had ever come out of an Islamic country. When people, rather baffled, pointed out the developments in mathematics, astronomy, and medicine that had come out of the Islamic world, the response was "yeah, sure, but that was A WHILE AGO".

If something doesn't encourage innovation, it doesn't encourage innovation. You don't really get to say, yeah, sure, tropical climates gave us the entire concept of tool use and metalworking to begin with, but that doesn't count because ... because.
posted by kyrademon at 1:51 AM on November 18, 2012 [1 favorite]

The well is very helpful if you don't have very precise measuring instruments. Instead of two crude angular measurements there was only one crude angular measurement. Also, the idea of doing the measurement at all [...]

These are arguments that the environment near the tropics is conducive to this measurement being made. I agree with that. What I questioned was justsomebodythatyouusedtoknow's actual claim, which was:

that measurement technique could only be performed in the tropics*

Moving goalposts, again.
posted by stebulus at 8:20 AM on November 18, 2012

Moving goalposts, again.

To be clear, I was admitting that they could be moved a bit in that case in a direction counter to my own original argument.
posted by localroger at 8:24 AM on November 18, 2012

Arbitrarily declaring that only the technological developments in the 0.2% of most recent human history "count" is very strange

It's not strange when the last sentence of the comment that started this pedantic derail was this:

There might be the remains of an entire civilization down there under the ice. They might even have achieved space flight; there are obvious reasons why they might have avoided those parts of the world ruled by monsters. I particularly favor the idea when I'm in a SFnal mood that the asteroid strike was an attempt at asteroid mining which went horribly wrong...

I guess everyone was too intent on telling their hobby horses to giddyup to the reply box to read on to the kind of civilization I was obviously talking about.
posted by localroger at 9:22 AM on November 18, 2012

No, I understand exactly what kind of civilization you were talking about. I started a long post trying to explain what I meant, but, honestly, you're right, it's a derail. Forget it, believe what you like.
posted by kyrademon at 9:59 AM on November 18, 2012

I can't believe you all missed the point. It was a planet, do you hear me? The Death Star blew their world up when they began to develop their psi-warrior skills. Check out the secret Hubble photos that NASA won't show you, and you'll see. BN-3356 has remnants of an alien building, probably a fast-food store. Look it up if you don't believe me.

The truth is O U T T H E R E .
posted by mule98J at 10:19 AM on November 18, 2012 [1 favorite]