"The more I find out, the less I know."


San Francisco Scuba Map, circa 2050

Sunday - June 15, 2008 02:23 PM

Climate Change Skeptic: "I don't see what the big deal is. The Earth's atmosphere has had CO2 levels this high in the past."

Climate Change Believer: "Yes, but the last time that happened, sea level was 300 feet higher than it is today."
I'm not sure where I heard that exchange, and I'm not sure if it's true, but it inspired me to perform an interesting thought experiment: what would be underwater if the sea level rose 300 feet?


All of Florida and much of the southeast United States would become a shallow sea. The Mississippi would empty into the Gulf of Mexico somewhere around the confluence with the Ohio River at the southern tip of Illinois.

And San Francisco? It would look something like the map I made (click on the thumbnail for a full-size version). To produce this Map of San Francisco Under 300 Feet of Water, I downloaded a 7.5 minute topographic map from the U.S. Geologic Survey, then traced around the 300 foot contour in Photoshop. I left the water slightly transparent so you can see the layout of the submerged streets and other features.

Here in Minnesota we would have nothing to worry about--except for all the people moving in to enjoy our newly moderate climate, thanks to the improved proximity to the Gulf of Mexico (hurricanes might become an issue, too). All of Minnesota is well above 300 feet in elevation.

As much fun as it was to make the Scuba Map of San Francisco, 300 feet of sea level rise is close to an impossible scenario. Even if all the ice caps (Antarctica and Greenland) completely melted, sea level would only rise around 200 feet--and no scientists I know of think that complete melting the Antarctic ice sheet is anything close to a realistic possibility.

A more likely outcome of global warming is a sea level rise of a foot or two over the next century--devastating enough, to be sure, but not nearly as much fun to put on a map of San Francisco.

Posted at 02:23 PM | Permalink |

Musing on Moisture

Monday - May 21, 2007 02:54 PM

Over the weekend I visited the Science Museum of Minnesota. On the floor in the lobby, they have a giant color map of the Earth, colored according to vegetation (similar to this one, but with more realistic colors).
One thing struck me which I'd noticed before, but hadn't really thought about: there's an amazing fraction of the Earth's land surface covered by desert or near-desert. Most of Africa, a big chunk of equatorial Asia, nearly all of Australia, maybe a third of North America: all relatively (sometimes extremely) arid.

What's more, this dry land is disproportionally near the equator, meaning that it gets a lot of solar energy.

If someone could figure out a way to economically irrigate large parts of this landmass, it could perhaps double or triple the Earth's capacity to grow crops for food or biofuels (of course, the whole reason it's desert is because there's not a lot of available fresh water).

If someone could figure out a way to economically transport solar power from the Sahara to Europe or China, it could power the world's economy with energy to spare.

All of which just reinforces my conviction that we don't have an energy problem. We have a fuel problem, a solar power capture and storage problem, and a carbon dioxide problem.

But there's plenty of energy.

Posted at 02:54 PM | Permalink |

A Weird Month

Monday - January 22, 2007 09:57 PM

I've been slow on the blogging here lately....maybe sometime I'll get around to writing about the whole saga of the past couple months. But not yet.
Today I'd like to draw your attention to this little gem of a commentary (via Amy Alkon, the blogger I love to hate) about global warming.

Here in the Twin Cities, for example, we've had only one night with solidly below-zero temperatures so far this winter (-8 at our home, a week ago), and it's looking like that may have been the coldest night of the season. Normally we get at least one or two hard arctic blasts, where temperatures dip well below zero for a week or so at a stretch, and we usually bottom out in the teens below zero. Sometimes we kiss -20 for a moment.

We've also had very little precipitation, with the storms all tracking well south of here. Parts of New Mexico have gotten more snow than Duluth.

So when the climatologist does the radio call-in show, someone always asks, "Is this weird weather the result of global warming?"

The scientifically nuanced answer always goes something like this: "We can't really tell if one season's weather is the result of global warming or not, but we think the climate is heating up over the long term." Global warming true believers don't like this, because it sounds wishy-washy. Skeptics don't like it, because it says the Earth is getting warmer. Neither side seems particularly willing to consider that the actual truth probably lives somewhere between the "Greenland is getting colder" camp and the "Humans are going the way of the dodo" alarmists.

Here's the unvarnished truth:

Fact 1: The Earth is getting warmer. This is measurable, and while there are local changes against the trend in places, all the best and most careful data show that the planet, as a whole, is ever so slightly warmer today than it was 25 or 50 years ago.

Fact 2: Atmospheric carbon dioxide is higher today than it was 100 years ago, has been steadily rising for as long as records have been kept, and is probably higher today than any time in the past several thousand years. Methane has also been rising, but the records aren't as good, and methane doesn't last as long in the atmosphere anyway.

Scientific Conclusion 1: The increase in the Earth's temperature is likely because of the increase in carbon dioxide (and methane). With something as complex as and entire planet it can be hard to be 100% certain of cause and effect, but the theory is sound and the effects are what we'd expect. So it is a reasonable conclusion--and there aren't many credible alternative explanations for the observed temperature increase.

Scientific Conclusion 2: The increase in carbon dioxide (and methane) is almost certainly because of human activities, especially the burning of fossil fuels. All that carbon dioxide has to come from somewhere, and the number of possible somewheres is very limited. It is a fact that we've been digging up ancient deposits of organic material for over a century and burning it at a tremendous rate, which is just about the only source anyone has been able to suggest for where all this stuff is coming from. Again, it can be hard to know with 100% certainty (it isn't like the carbon dioxide from nonhuman sources is a different color), but there simply aren't many credible alternative explanations for the observed data.

Unsupported Malarky 1: "We're all doomed!" People are always drawn to the dramatic, catastrophic scenario--even when the odds are slim. In truth, the Earth has suffered far greater environmental catastrophes in the past and generally come out of them OK. Humans are a remarkably adaptable species--even more so now that we have tons of technology at our disposal--and we've survived repeated ice ages and subsequent warming in the past. The worst case scenario is likely a generation or two of mass displacement, large-scale population shifts, extinction of some charismatic megamammals like the polar bear, and then....we adjust. Not to be too flip about it, but the human race survived the extinction of the wooly mammoth (also likely because of human activity, by the way), and we'll survive the loss of other species as well. (This is the worst case scenario, by the way--the reality is likely to be somewhat milder.)

Unsupported Malarky 2: "If we're not doomed, then there's no need to worry." People who think there's no need to plan for the future are just as mistaken as the doomsayers in the long run. Even if you are skeptical about the reality or severity of global warming, there's no denying the fact that fossil fuels are a limited resource and in a century or so we will be forced to find alternate energy sources as even the coal starts to get scarce. So switching to low-carbon energy is simply a fact we'll have to deal with for one reason or another, and pretty soon as measured by the grand sweep of history.

Speaking of the Grand Sweep of History: Roman civilization lasted about 1,000 years, from the beginning of the Republic to the end of the Roman Empire. Imperial China lasted about 2,000 years, and the ancient Egyptian civilization lasted something like 3,500 years. In contrast, the era of fossil fuels, from the beginning of the Industrial Revolution until we run out of economically extractable coal, oil, and gas will only last 400-500 years. When future historians write about our time, it may be notable for many things, but the longevity of fossil fuels as an economical energy source will not be one of them.

Posted at 09:57 PM | Permalink |

Zero-G Water Droplets

Tuesday - November 07, 2006 02:27 PM

All I can say is....wow. Cool. I can't wait to try it myself.

Posted at 02:27 PM | Permalink |

Global Drying?

Monday - August 14, 2006 09:09 PM

I'm not a skeptic about global warming, but I am skeptical of a lot of the specific predictions being made for the specific effects of climate change. I don't think we have anything close to the depth of knowledge to understand how a warming atmosphere will change the particular climate patterns for a given region. In addition, some of the predictions simply don't make sense, and the media tends to present them without any context and in the most alarming possible manner.
Case in point: an article today in the Guardian says that global warming could cause massive forest fires and deforestation (among other things). The Guardian isn't exactly known for its balanced views on climate change, but this article seemed particularly over the top.

Presumably (the article doesn't actually say), the predicted forest fires would be because the burning areas would not only get warmer, but drier too. But from the highest possible level, one would expect that a warmer climate would be, on the whole, wetter, not drier, because warm air holds more water vapor, and warm water evaporates faster.

In fact, one would expect that a warmer climate should be, on the whole, a lot wetter, since both the evaporation rate of water and the water capacity of air go up exponentially as the temperature increases.

Unless I'm missing something, and since I'm not a climate expert, I might be. Feel free to leave me a comment if you know better.

But the media coverage gives me no way to know whether I'm missing some piece of the puzzle, or if regions other than the ones listed will get wetter (the areas predicted to lose forests are "Europe, Canada, Asia, Central America, and Amazonia," which seems to cover about 80% of the land mass of the planet). Furthermore, there's no explanation of why those areas will get drier, and therefore no way for me to understand how reliable the climate model might be.

All I'm left with is the impression that, contrary to what basic physical intuition tells me (that a warmer climate should be wetter), huge swaths of land are predicted to become desert as the climate warms, with no explanation as to the mechanism or the logic. And I know that the models are still very crude, with huge gaps in our understanding of the basic mechanisms.

So you'll pardon me if I'm skeptical about this and similar articles. We'll just have to wait to find out what really happens as the Earth heats up.

Posted at 09:09 PM | Permalink |

Global Catastrophe

Thursday - June 29, 2006 09:50 PM

Michael Crichton, the science-thriller author, has had his share of abuse since he infamously came out as a skeptic of global warming a few years ago. I haven't paid much attention to the kerfuffle (I never took him that seriously as an expert on scientific matters to begin with), but I ran across a presentation he gave on complexity and the environment a few months ago.
I find that, despite the fact that I don't take him seriously as a scientist, he makes a strong case for a couple of points:

1) Humans have a long and remarkable history of predicting imminent global catastrophe (he doesn't go back that far, but I know of predictions dating back to the middle ages), none of which have turned out to be true in retrospect. Therefore, we should treat all such claims (including, by implication, the more extreme predictions relating to climate change) with a huge amount of skepticism.

2) We really don't understand in any meaningful sense how extremely complex systems like global climate react to artificial changes (except, perhaps, in the most extreme and/or general cases).

I agree with both of these points (even before reading his article), though I don't agree with the implied conclusion that we shouldn't worry about the effect of increasing carbon dioxide in the atmosphere. As a general rule, I think we should tread lightly when it comes to making big changes in things we don't really understand.

On the first point, the simple fact that life continues to exist on Earth, despite billions of years of every kind of abuse the solar system can throw at us is very strong evidence that, rather than being fragile, our planet's overall climate is actually extremely robust. Sure, there have been times when many species died out at once because of climate change, but those events can be counted on the fingers of one hand despite billions of years of history, and they appear to have been triggered by truly cataclysmic events like giant meteor impacts. Events far greater than anything humans are even capable of producing at this stage in our development. Yet life continues.

On the second point, it is true that there are very sophisticated computer models, but even the best model makes absurd simplifications, and there are big swaths of knowledge about climate dynamics which are still completely unknown. We do not know the effect that these as-yet-unknown factors will have on the climate. For example, just in the past week there have been news reports that the glaciers in Greenland appear to be melting far faster than predicted by anyone's models. This trend, if it continues, will have a significant impact on global sea levels and the climate of Europe. Yet we do not yet understand why it is happening, what might accelerate the trend, or what might make it stop or reverse (though there are already lots of theories).

My own opinions on global warming run more-or-less as follows:

1) It is indisputable that atmospheric levels of carbon dioxide are climbing as a direct effect of human activity. We should, as responsible citizens, work to mitigate this change in an expeditious but deliberative (not panicked) manner.

2) It is almost certain that, as a direct result of the increase in CO2 levels, the average global temperature is increasing and will continue to increase. Even if we could somehow end all CO2 emissions tomorrow, it is probably too late to stop a meaningful change.

3) As anyone who lives in Minnesota knows from experience, the "average temperature" is the mythical midpoint between extremes of hot and cold. Just because the global average temperature is increasing does not imply that any given spot will get warmer. Some places will get warmer, and other places will get colder. Some places will get drier, and others wetter. Our current understanding of climate dynamics can't make any but the crudest predictions about local or regional climate changes.

4) The more alarmist predictions of social breakdown, chaos, dogs and cats living together, etc. are bogus. There is likely to be displacement, hardship, and significant economic harm to some groups of people, but nothing worse than the run-of-the-mill volcanoes, earthquakes, and other natural disasters we already deal with regularly (for example, a quarter of a million killed in an earthquake/tsunami--a disaster unrelated to global warming, yet something of this magnitude happens every couple hundred years or so).

5) Some major cities may have to be abandoned because of rising sea levels. Yet the experience of Hurricane Katrina shows that even the near-abandonment of New Orleans is something we can deal with without collapsing the fabric of our society (aside from the affected city itself). The city is unlikely to have even half its former population any time in the near future, and if New Orleans is hit by another major hurricane in the next few years it will almost certainly be permanently abandoned or nearly so. Yet people's lives will go on with out much disruption most everywhere else: it would be a disaster, but not a disaster of such magnitude that life and society as we know it would end. We will deal, as we always do.

So to summarize, I think we have already done a lot of whatever damage we're likely to do. While we should take steps to reverse what we've already done, the fact of the matter is that we're simply going to have to cope with the changes. But I don't see the changes as anything more than what civilizations have had to deal with in the past. The planet is littered with Great Cities which are abandoned or mere shadows of their former selves (plus a couple which got blown to smithereens in volcanic eruptions). Adding a few more to the list over the next couple hundred years just isn't that unusual when you look at it from the perspective of 6,000 years of human civilization.

I don't know if this makes me an optimist, a pessimist, a realist, or a skeptic on global warming (maybe it makes me a Buddhist: we're going to get what we deserve, and we'll just have to make the most of it). But I think its a much more balanced and reasonable attitude than the overheated rhetoric I've been hearing from both sides lately.

Posted at 09:50 PM | Permalink |

Science Education

Saturday - May 27, 2006 02:42 PM

I've had six years of college education in physics, followed by three years of graduate school. I've taught college-level physics, and yet I've never had or taught a class where the professor gave this exam:
Science 101 Exam

The professor performs some experiment in front of the class which the class hasn't seen before. The experiment is explainable by material taught in the class, but not obvious.

Question 1: Provide one physically plausible explanation for why the experiment turned out the way it did.

Question 2: Provide a second, distinct, physically plausible explanation for why the experiment turned out the way it did.

Question 3: Describe an experiment which will determine which of your two explanations is the correct one.

(More advanced classes would be asked to derive equations describing each of the explanations and their experiment).

This simple three-question exam distills the essence of what science is and how it is done in the real world. Practicing scientists spend their entire careers working on different bits of this exam (that fraction of their careers not spend on departmental politics, that is).

Yet I've never seen this type of exam actually given. Why?

Posted at 02:42 PM | Permalink |

The Science of Being Blonde

Monday - February 27, 2006 03:33 PM

An article I saw yesterday makes the case that blonde hair evolved as a way for women to attract mates at a time when men were hard to find. What can I say: it worked on me.
It was interesting to read, though, that natural blondes are gradually becoming extinct (according to the article, the last natural blonde will likely be born in Finland in the year 2202--an unnatural degree of precision which should have some science writer drummed out of the corps). It makes sense, if blonde hair evolved to attract mates, that it would slowly disappear now that anyone can have any color hair.

There are some interesting questions to ponder. For example, as naturally blonde hair becomes rarer and rarer, will people start working to preserve the trait? Will there be a Society for Preservation of Blonde Heritage, which will engineer mating opportunities between people with naturally light-colored hair?

When the last natural blonde dies, will she be stuffed and displayed in a museum, like the last passenger pigeon? Will future schoolchildren gaze wide-eyed at the astonishing variety of hair color people grew back in the 20th century?

The mind boggles. Truly.

Posted at 03:33 PM | Permalink |

Well, is it hard or not?

Friday - October 14, 2005 12:11 PM

Replicating the 1918 influenza strain is a remarkable feat of science, requiring astonishing dedication and the best and brightest minds working with state-of-the-art facilities. And we should worry that terrorists are about to do it.
Those are the two contradictory ideas in this remarkable column by Charles Krauthammer.

Can we please be clear on this? Is replicating the 1918 flu virus hard, or isn't it?

Because if it's hard, I'm not going to worry about guys doing it in a cave in Afghanistan. But if it's easy, then I don't see why we're making such a big deal about the scientific importance of it.

To be fair, I think Krauthammer has made the mistake of confusing knowing the DNA sequence of the virus and actually building a live infectious virus. This is an understandable mistake, given the popular idea (i.e. Jurassic Park) that once you know the gene sequence of a living thing, you know everything about it.

But the real world is very different. Sequencing DNA is relatively easy (as such things go), even if the samples you have are old and degraded. But building an entire organism from whole cloth is a different matter.

In order to get the entire organism, you have to not only have a complete DNA sequence, but you also have to build all the biochemical machinery and structures which allow that strand of DNA to function, replicate, and (in the case of influenza) become infectious.

It's like the difference between having a copy of Microsoft Office on CD-ROM, and having a complete computer with Office installed. Without the computer, the CD-ROM is just a pretty piece of plastic and aluminum.

Krauthammer also makes good points about the physical security of the virus sample. Now that live virus exists, it is orders of magnitude easier to steal a sample than it is to make your own.

But these considerations are no different than for other infectious agents like ebola, smallpox, and (potentially) current strains of bird flu. The appropriate response is not to panic that there is a new infectious agent in the world, but rather to make sure that all highly dangerous specimens are properly contained. This is no different than the problem we already faced, and the implication that the 1918 strain presents some brand-new risk is simply wrong.

Posted at 12:11 PM | Permalink |

Bird flu

Tuesday - October 11, 2005 04:07 PM

Bird flu has been all over the news lately. I'm trying to decide exactly how worried I should be.
News reports will, of course, tend to emphasize the imminent danger. That's what sells newspapers, and that's what people "want" to hear. "Nothing to see here" just doesn't capture anyone's attention.

For example, recent reports about research on the 1918 flu strain suggest that it was very similar to today's bird flu, the implication being that the bird flu could be just as deadly this time around. But lest anyone forget, after killing tens of millions of people, the 1918 virus disappeared completely. So completely that researches had to exhume old corpses in order to find virus samples to work with.

That suggests an alternate interpretation: that the 1918 strain killed pretty much anyone susceptible to that particular virus. Anyone alive today may have inherited some natural immunity. Do I trust my life to that notion? Of course not, but you never hear about the possibility of natural immunity in the media, even though the idea seems at least as plausible as the possibility that the same virus released today would be just as bad or worse as the last time around.

Similarly, you hear a lot of prognostications about how quickly the virus would spread globally in an era of air travel. But SARS was fairly contagious yet didn't turn into a global pandemic, thanks in part to quick action from health authorities. Would bird flu be like the 1918 pandemic, or like SARS? We don't know the answer to that question.

But we do know that pandemics of various diseases occur once every generation or two throughout history. The last one was in 1968 (the Hong Kong Flu), and was the third influenza pandemic in the 20th century (there was also a cholera pandemic). There will be a global pandemic sometime in the future, possibly the near future, and there will be a pandemic after that and a pandemic after that.

Rather than obsessing about the current strain of bird flu (which might or might not turn out to be a major killer), it seems more prudent to think about common-sense ways to deal with pandemics generally.

Stockpiling Tamiflu, for example, might help if the next pandemic is bird flu (or it might not: Tamiflu is not effective against all strains of bird flu). But Tamiflu will do you absolutely no good if the next pandemic is ebola, Lassa fever, or some other disease.

But telecommuting could significantly improve your survival chances no matter what form a pandemic takes, since it would significantly reduce your exposure to other people. And with gas hovering around $3/gallon, telecommuting is attractive for other reasons.

On a local and national scale, efforts may be best spent on general health measures, such as making sure hospitals have enough excess capacity for an outbreak, and quarantine plans are in place. Money spent there will be helpful in a wide variety of scenarios (including natural disaster and bioterrorism) instead of just the one scenario of bird flu.

I've heard predictions of all sorts of amazing gloom-and-doom in the case of a bird flu pandemic. Cities running out of food as truckers refuse to drive trucks into "plague cities." Power plants going offline when the engineers die. That sort of thing. I don't believe it for a minute.

There have been pandemics of that magnitude in recorded history, where the disease disrupts the social order (the black death comes to mind), but they are very rare. We also know far more about sanitation and health care than we knew back in the 1300's. And those of us fortunate enough to live in a wealthy, developed nation have access to infrastructure and services which will help us identify, slow, and survive a pandemic.

Will there be another global pandemic? Yes. Perhaps even a major killer like the 1918 influenza.

But like most such natural disasters, it seems that the people most likely to be affected will be the poor and residents of less developed countries. Wealthy residents of wealthy countries will, for the most part, watch from a distance and worry.

Posted at 04:07 PM | Permalink |

Theories, Laws, Models, Hypotheses, Facts, and Leppik's Law

Friday - August 26, 2005 12:15 PM

Leppik's First Law of Empiricism: The empirical support for a scientific theory is inversely proportional to the grandiosity of the name.

Corollary: Leppik's First Law of Empiricism can be applied to Leppik's First Law of Empiricism.
Science deals with two types of information: experimental data and observations about the world around us; and ideas which help explain, understand, and predict the data and observations. Of course, it is impossible to explain 100% of the data, since some data is inevitably wrong, but in some fields like physics and chemistry scientists have done an amazingly good job. In other fields, like economics, not so good.

Scientists use a lot of different names for their ideas: Laws, Theories, Models, Hypotheses, and so forth. Some of these names imply absolute inviolability ("Law") while others seem to imply more tentativeness or uncertainty ("Model" or "Theory").

But the scientific theories with the most data behind them and the strongest ability to explain observed facts also tend to have the most tentative-sounding names.

Let's take some examples:

Newton's Laws (physics): Newton's Laws are taught in beginning physics classes, and are very useful when calculating the motion of stuff that isn't too big, too fast, too small, too slow, too heavy, or too light. Outside this range, Newton's Laws have been replaced by the Theory of General Relativity and the Theory of Quantum Mechanics.

Theory of Evolution (biology): The most valuable tool in the biological sciences, the Theory of Evolution explains all kinds of observations, many of which were impossible to make before Darwin proposed the idea well over a hundred years ago. Evolution predicts that different fossils will be found in different rock strata, that different species will have many similar gene sequences, that isolated populations of a species will have observable differences from the main population, and many many other observations. Despite this scientific success, biblical creationists (or "intelligent design" proponents as they call themselves today) never tire of claiming that Evolution is "just" a theory.

The Standard Model (physics): The Standard Model is one of the most successful scientific theories ever, as measured by its ability to predict experiments to lots of decimal places. It predicts the behavior of elementary particles like electrons and protons, as well as ones with weird names like gluons, quarks, and pions.

The Law of Supply and Demand (economics): The law of supply and demand has been around for over a century, and basically predicts that as prices go up, demand goes down, and supply goes up (and vice versa). It makes a lot of sense in theory, but has been tested (at best) only in extremely limited circumstances. Supply and Demand assumes that everyone is at least mostly rational, an assumption which can be disproved by simply standing at the entrance to a Wal-Mart on the day after Thanksgiving. Supply and Demand also fails to explain such common behaviors as hoarding (demand goes up when price goes up) and loss adversity (refusing to sell something like a house or stock in a company at a loss, even if the market value is far below the price paid).

Hubble's Law (astronomy): Hubble's Law is the idea that the further away from us distant objects are in the universe, the faster they appear to be moving away. This is true in the broadest sense, but only if you look at lots of distant objects and sort of average them out. In reality, Hubble's Law should be Hubble's Rule Of Thumb (or if you prefer alliteration, Hubble's Heuristic). On a related point: Hubble's Constant turns out to be not so constant after all.

The Big Bang Theory (cosmology): The name sounds lighthearted, maybe even derisive (in fact, the name was originally coined by opponents of the Big Bang Theory as a way to mock it), but there's little scientific doubt today that the universe began a finite time in the past, and expanded from very small size and high density to what we observe today. In fact, about the only people who don't accept the Big Bang are the same people who don't accept Evolution, and for pretty much the same reasons. The Big Bang explains Hubble's Law, and is closely related to The Inflationary Model, which is a generally-accepted mathematical explanation of the large-scale structure of the universe.

Posted at 12:15 PM | Permalink |

Tenth Planet

Sunday - July 31, 2005 12:23 PM

2003UB313 lacks a certain poetic flair we expect from the names of our planets.
Of course there will be a permanent name assigned at some point.

My I humbly offer the name "Shiva"?

I offer two reasons:

First, it is about time we acknowledge a mythology other that European in the names of our planets.

Second, in Hindu mythology Shiva is "The Destroyer." If there is still any currency to the idea that a planet-size body outside the orbit of Pluto occasionally sends big comets hurtling to the inner solar system and creating mass extinctions (such as the dinosaurs), then 2003UB313 could be that planet. Naming it for the mythological destroyer of the world seems only fitting.

Posted at 12:23 PM | Permalink |

Strung Along

Wednesday - March 16, 2005 08:14 AM

For anyone interested in physics, I highly recommend this article about string theory.
Modern physics has some big problems: there are two different theories of How Things Work, but they don't fit together. Einstein's General Relativity has passed every experimental test we can throw at it, and explains how the universe works on the scale of solar systems, galaxies, and bigger. At the other end of the spectrum, various quantum theories combine into the Standard Model, which has passed every experimental test we can throw at it, and explains how the universe works on the scale of molecules, atoms, and smaller.

In the middle, at human-scale sizes and energies, they both reduce to classical Newtonian physics.

But the two theories are basically incompatible. There is no good explanation of How Things Work in places where both theories could apply, such as extreme gravitational fields packed into supersmall sizes.

The two theories are very different in other ways, too. General Relativity was the brilliant work of one genius--Einstein--who came up with the whole thing based on the logical extension of first principles. General Relativity has remained essentially unchanged since it was created in the first decades of the 20th century, and it may be fair to say that Einstein was at least a century ahead of his time. GR relies on only two parameters, the speed of light and the gravitational constant, and is probably the most elegant scientific theory ever devised.

The Standard Model, on the other hand, has been the work of many physicists and has grown over a century as new experimental evidence gets incorporated into the theoretical framework. Significant refinements continue to be made even to this date (for example, until the 90's the theory held that neutrinos have no mass. We now know that they do). The Standard Model requires a menagerie of fundamental forces and particles, each with its own fundamental parameters, and no good reason for why they are what they are. Compared to GR, the Standard Model is inelegant, arbitrary, and messy.

String theory tries to resolve the conflicts between the two, but doesn't appear to have any experimental evidence.

In many ways, I think the conflict between General Relativity and the Standard Model is similar to the crisis at the end of the 1800's, when (then current) theories of physics failed important experimental tests. The difference is that now we have a situation where there's too many theories and no experiments to guide them, whereas a century ago the problem was the opposite.

The resolution will probably be the same: new physics (probably driven by new experiments) will lead us to a much deeper understanding of the universe. Odds are, the result will be something much weirder and more beautiful than anything anyone has thought of up to now.

Posted at 08:14 AM | Permalink |


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