Tag Archives: modelling

Blueprint for a Dying Earth: what would happen if the world stopped spinning?

I’m not sure whether I’m a sucker for outlandish “what if?” speculation because I’ve always read science fiction, or whether I read sf because I have some innate speculative itch that I need to scratch. Whichever it may be, this is the sort of thing that pushes a whole lot of my buttons: using modelling software to determine what Planet Earth would look like were it to – for some reason – stop spinning [via BoingBoing].

The lack of the centrifugal effect would result in the gravity of the earth being the only significant force controlling the extent of the oceans. Prominent celestial bodies such as the moon and sun would also play a role, but because of their distance from the earth, their impact on the extent of global oceans would be negligible.

If the earth’s gravity alone was responsible for creating a new geography, the huge bulge of oceanic water—which is now about 8 km high at the equator—would migrate to where a stationary earth’s gravity would be the strongest. This bulge is attributed to the centrifugal effect of earth’s spinning with a linear speed of 1,667 km/hour at the equator. The existing equatorial water bulge also inflates the ellipsoidal shape of the globe itself.


Today, all three world oceans are connected. This creates a global ocean with basically one sea level. As a consequence of rotational slowdown, the outline of the global ocean would continuously undergo dramatic changes. Equatorial waters would move toward polar areas, initially causing a significant reduction in depth while filling the polar basins that have much less capacity. As regions at high latitude in the northern hemisphere become submerged, the areal extent of the northern circumpolar ocean would rapidly expand, covering the vast lowlands of Siberia and northern portions of North America. The global ocean would remain one unit until the rotation of the earth decreased to the speed at which ocean separation would occur. The interaction between the inertia of huge water bodies and decreasing centrifugal force would be very complicated. As the consequence of steady slowdown of earth’s rotation, the global ocean would be gradually separated into two oceans…

Sure, so it’s pretty unlikely to ever happen… and if it did, speculating about topography would be the last of our concerns, I imagine.

But what if…?

[ As a side note, that’s a great way to virally advertise a piece of software that would otherwise only be of interest to 0.001% of the world’s population. Kudos! ]

Attention economics, redux: why supermodels are like toxic assets

Remember me linking to that article that compared the inflationary bubble in the cult of celebrity to the sub-prime mortgage crisis? Well, here’s a similar (and slightly more serious) piece that explains how supermodels are similar to toxic assets [via MetaFilter]:

Coco [Rocha] is what economists would call a winner in a “winner-take all market,” prevalent in culture industries like art and music, where a handful of people reap very lucrative and visible rewards while the bulk of contestants barely scrape by meager livings before they fade into more stable and far less glamorous careers. The presence of such spectacular winners like Coco Rocha raises a great sociological question: how, among the thousands of wannabe models worldwide, is any one 14 year-old able to rise from the pack? What makes Coco Rocha more valuable than the thousands of similar contestants? How, in other words, do winners happen?

The secrets to Coco’s success, and the dozens of girls that have come before and will surely come after her, have much less to do with Coco the person (or the body) than with the social context of an unstable market. There is very little intrinsic value in Coco’s physique that would set her apart from any number of other similarly-built teens—when dealing with symbolic goods like “beauty” and “fashionability,” we would be hard pressed to identify objective measures of worth inherent in the good itself. Rather, social processes are at work in the fashion modeling market to bequeath cultural value onto Coco. The social world of fashion markets reveals how market actors think collectively to make decisions in the face of uncertainty. And this social side of markets, it turns out, is key to understanding how investors could trade securities backed with “toxic” subprime mortgage assets leading us into the 2009 financial crisis.

Well worth a read; it’s interesting to see someone looking at a market in terms of its social construction rather than as a bunch of mathematical abstractions and assumptions. One of the things that has frustrated my research into economics is the way it always seems to be portrayed as a coldly rational science, without any attempt to understand or deconstruct the emergent social consensus that drives it. This is almost ertainly due to me looking in the wrong places, so if anyone has any suggestions for good sources of social and/or behavioural economic literature that won’t baffle an inquisitive layman, please pipe up in the comments.

Google’s Building Maker: crowdsourcing the world’s architecture

Valencia, Spain as seen in Google EarthIs there anything that can’t be crowdsourced? Google sure don’t think so, as they’ve just announced another new project for Joe Public to muck in on. Google Building Maker will be used to populate Google Earth with 3D models of major buildings:

We like to think of Building Maker as a cross between Google Maps and a gigantic bin of building blocks. Basically, you pick a building and construct a model of it using aerial photos and simple 3D shapes – both of which we provide. When you’re done, we take a look at your model. If it looks right, and if a better model doesn’t already exist, we add it to the 3D Buildings layer in Google Earth. You can make a whole building in a few minutes.

It’s entirely browser-based, too, so no compatibility problems. Of course, you don’t get the freedom of Second Life, where you can build any damned building you feel like… but then learning how to build well in SL can take weeks of practice, whereas Google have aimed to make it as easy as possible. Which is a sensible move if you want people to do work for free, I guess… [image by Visentico/Sento]

Virtual economies, virtual reputations and virtual business suits

Metaverse office space?Once the hype over Second Life died out, virtual worlds kinda disappeared from the high-profile headlines. But there’s still plenty of stuff going on in the metaverse, not least its use as a test-bed for theories to apply in reality. [image by Ramona.Forcella]

Economics is a popular choice; we’ve reported before on the bank runs and currency collapses of EVE Online, and now Edward Castronova – author of Synthetic Worlds, which should be your first port of call if you’re even vaguely interested in metaverse economics – is leading a team who’re examining the economy of EverQuest II. [via SlashDot]

Researcher Edward Castronova, professor of telecommunications at Indiana University, said researchers can learn almost anything about human society in games as they really are human societies.

However unlike real society they can be observed and tweaked.

“We can do controlled experiments in virtual worlds, but we can’t do that in reality,” said Castronova.

“Controlled experimentation is the very best way to learn about cause and effect. We are on the verge of developing that capacity for human society as a whole.”


After studying 314 million transactions within the fantasy world of Norrath in “EverQuest II,” including trading in-game goods like armor, shields, leather, herbs and food, the researchers were able to calculate the GDP of one of the game servers (the back-end computer that hosts thousands of players in one world).

As more people opened accounts and flocked to Norrath, spending money on new items, researchers saw inflation spike more than 50 percent in five months.

Game economies are, much like real economies, predicated on more than just a currency. Reputation scores are a big part of game economies (and many social networks, too), but the problem with “karma” systems is that they’re usually implemented in a way that renders them pointless, and which leads to the formation of in-game “mafias” [via BoingBoing]:

There can be no negative public karma-at least for establishing the trustworthiness of active users. A bad enough public score will simply lead to that user’s abandoning the account and starting a new one, a process we call karma bankruptcy. This setup defeats the primary goal of karma-to publicly identify bad actors. Assuming that a karma starts at zero for a brand-new user that an application has no information about, it can never go below zero, since karma bankruptcy resets it. Just look at the record of eBay sellers with more than three red stars-you’ll see that most haven’t sold anything in months or years, either because the sellers quit or they’re now doing business under different account names.

A different (though related) kind of reputation will be bothering the business crowd, however, and the Gartner firm of analysts is convinced that in less than five years, 70% of businesses will have issued avatar dress-codes to their employees [via SlashDot]:

“As the use of virtual environments for business purposes grows, enterprises need to understand how employees are using avatars in ways that might affect the enterprise or the enterprise’s reputation,” said James Lundy, managing vice president at Gartner, in a statement.

“We advise establishing codes of behavior that apply in any circumstance when an employee is acting as a company representative, whether in a real or virtual environment.”

This puts me in mind of a recurring motif in William Gibson’s novels, where he repeatedly makes the point that the most powerful and resource-rich virtual environments will be the ones that look subtle and understated, while the low-budget hucksters will dress to impress with excessive bling and extravagant eye-candy. The subtle grunge and mundane decay of reality is harder to simulate than grandiose overstatement; as in real life, it’ll be wise to tread lightly around the ostentatious.

Not interested in playing games or doing business in the metaverse? Well, you could always go learn to speak a dying language.

Modelling the climate

weatherAn interview with Gavin Schmidt over on Edge explores the nature and development of climate modelling:

What we have decided, as a scientific endeavor, is to extrapolate as much as we can from our knowledge of the individual processes that we can measure: evaporation from the ocean, the formation of a cloud, rainfall coming from a cloud, changes in the wind patterns as a function of the pressure field, changes in the jet stream. What we have tried to do is encapsulate those small-scale processes, put them altogether, and see if we can predict the emerging properties of that fundamental complex system.

He explores the sometimes contradictory predictions of different climate models:

In the same way that you can’t make an average arithmetic be more correct than the correct arithmetic, it’s not obvious that the average climate model should be better than all of the other climate models. So for example if I wanted to know what 2+2 was and I just picked a set of random numbers, the answer by averaging all those random numbers is unlikely to be four. Yet when you come to climate models, that is kind of what you get. You get all the climate models and they give you some numbers between three and five and they give you something that is very close to four. Obviously, it’s not pure mathematics — it’s physics, it’s approximations, there is empirical tuning that goes on.

You need to have some kind of evaluation. I don’t like to use the word validation because it implies a kind of binary/true-false set up. But you need an evaluation; you need tests of the model’s sensitivity compared to something in the real world that can give you some credibility that that model has the right sensitivity. That is very difficult.

It is a lengthy essay/video interview but well worth the read/watch, as it is refreshing to hear firsthand from a professional climatologist.

[at Edge][image from Nicholas T on flickr]