Ouch! That was quite the rumble. Enough to freak out all the cats. This is the third significant earthquake I experienced here in Ottawa; it may not have been the strongest as measured by instruments, but it certainly felt the most, hmmm, “hostile” sounds like the right word.
Hayabusa, or at least the part of it that was meant to survive atmospheric re-entry, has returned. Hayabusa, also known as MUSES-C, is a Japanese spacecraft, the first ever asteroid sample return mission. Unfortunately it is not yet clear if it has actually managed to collect any samples. Even so, it’s been one impressive mission.
This Homer Simpson is one smart fellow. While he was trying to compete with Edison as an inventor, he accidentally managed to discover the mass of the Higgs boson, disprove Fermat’s theorem, discover that we live in a closed universe, and he was doing a bit of topology, too.
His Higgs mass estimate is a tad off, though. Whether or not the Higgs exists, the jury is still out, but its mass is definitely not around 775 GeV.
This is going to remain a memorable picture for some time to come:
It’s not every May, after all, that we measure 35.8 degrees Centigrade in what is supposedly the world’s second coldest capital city.
Welcome home, Atlantis, for the very last time.
After being in service for a quarter century, her next trip is to a museum somewhere.
Sitting on the surface of Mars, a space probe that was not designed to survive the Martian polar winter did not survive the Martian polar winter. Not exactly a surprise.
The surprising bit is that another space probe orbiting Mars, designed to operate for two years but still working fine after four, has been able to snap high resolution pictures of Phoenix, which tell us what likely happened: the weight of carbon dioxide snow and ice broke Phoenix’s solar panels.
It is amazing that we have this kind of infrastructure around Mars.
It seems that the German news magazine Spiegel managed to do the impossible: provide an impartial, balanced assessment of the story behind Climategate.
And by “balanced”, I don’t mean balanced in the American journalist’s sense, giving equal weight to both sides, no matter how ludicrous one side happens to be compared to the other, but balanced in the sense of not taking sides, not assuming guilt, and assessing the faults of all the participants regardless of which side they represent.
What I am reading is very discouraging. Climate science should really be called climate politics, with a little bit of science thrown in just to provide fodder for arguments. Meanwhile, both proponents and opponents of climate change sometimes fail to get even the basic physics right; as a minor example, recently I felt compelled to write a short paper about the proper use of the virial theorem in a planetary atmosphere, after reading way too much uninformed discussion by supposed experts online.
Of course way too much is at stake. Trillions of dollars, for starters, and quite possibly the future of our planet. Could it be that this compelled some good people to embellish the truth a little? If that is the case, they did a huge disservice to the very cause that they champion. By compromising the one currency science really has, its objectivity, they increased the likelihood that the public won’t listen to them just when it matters most, should it prove to be the case that real sacrifices are necessary to keep the planet habitable.
That is not to say that taking climate scientists to court is the right answer. If that’s the cure, it’s worse than the disease. Worse yet, it will only ensure more entrenched positions and more secrecy, justifying the hostility towards “deniers”. That is not the way to do science. Informed skepticism should be welcome, but skepticism should be about questioning methods and deductions, not the honesty and integrity of researchers. Will climate science ever be like this? I sure hope so, otherwise we’re all in very deep trouble.
The long-awaited successor to the classic “Handbook of Mathematical Functions” by Abramowitz and Stegun has finally been released: its online version is available courtesy of the US National Institute of Standards and Technology. (It is yet another one of those often under-appreciated contributions of Uncle Sam to the world.)
I was watching the noontime local CTV news today. At around 12:39 (!), in three consecutive reports, the number 39 popped up. First, a report about a youth who is charged with vandalizing 39 tombstones. This report mentioned the number 39 several times, which is probably why I noticed that in the next report, one about the recent terrorism-related arrests in the US, footage shown in the background included the front door of a house bearing the number 39. At this time, I began paying attention. The next report was about Ottawa tourism advertisements in American newspapers; it didn’t seem likely that the number 39 would pop up there until the official being interviewed answered a question about funding and mentioned their 39 member hotels. That’s when I told my wife that this is getting a tad creepy.
The other day, I was watching a Stargate Universe episode in which one of the protagonists was reliving a part of his life while his brain was connected to an alien computer, and a particular number kept popping up as a clue. That number was 46, the number of chromosomes in a human cell. So that’s what makes 46 special. But what about 39?
Or perhaps all this was just a clever form of subliminal advertising for a Web site called The 39 Clues, which happens to be the first hit on Google when one searches for “39”?
Here’s an idea that only Dr. Strangelove, Edward Teller, or the Communist Party of the Soviet Union could come up with: nuke that oil leak at the bottom of the Gulf of Mexico. Apparently, it has been done before, and only one out of five attempts was unsuccessful. So how about that, folks? What’s a bit of radioactivity when you have an 80% success rate?
OK, I don’t usually play the geek game and look for nits to pick in television science programs. But…
Today’s gem comes courtesy of the Canadian History Channel and their Aftermath series, the first episode of which I just watched over the Internet. The show had many eyebrow-raising moments (and I don’t mean the implausible concept itself, about the Earth’s rotation slowing down to zero in a mere five years; I could get over that if the science had been right otherwise). This particular gem of a sentence, complete with fancy animation, especially caught my attention:
“The rotation of the Earth creates constant patterns of east-moving winds in the Northern hemisphere, and west-moving winds in the Southern. This is called the Coriolis effect.”
Oh really. I wonder if pilots flying in the Southern hemisphere know this.
When I started this here blog site, my intent was to write a lot about physics. I ended up writing a lot less about physics than I wanted to, in part because a lot of the physics I’m thinking about is “work-in-progress” which would not be appropriate to write about until, well, until it is appropriate to write about it!
But, there are a few exceptions. Lately, I’ve been thinking a lot about scalar-tensor gravity. Indeed, as I am waiting for the completion of a virus scan (could my recent computer troubles have been caused by a virus? I now took out my computer’s hard drive, put it in an external enclosure, and I am scanning it using a “known good” computer) I am thinking about it now.
Einstein’s gravity theory (tensor gravity) can be written up using the Lagrangian formalism. This is the infamous Einstein-Hilbert Lagrangian, which takes the form L = [(−1/16πG)(R + 2Λ) + LM]√−g, where G is the gravitational constant, R is the so-called curvature scalar, Λ is the cosmological constant, g is the determinant of the metric, and LM is the Lagrangian representing matter.
In one of the simplest modifications of Einstein’s gravity, Jordan-Brans-Dicke theory, the gravitational constant G is promoted from constant to field: it becomes variable, and a “kinetic term” is added to the Lagrangian representing the kinetic energy carried by this scalar field.
In this theory, gravity is still determined by the geometry of space-time. However, in addition to matter, there is this scalar field (which carries mass-energy and is thus a further source of gravity in addition to matter.) Then, this scalar field also determines the strength of coupling between matter and space-time (i.e., the extent to which a unit mass of matter bends space-time.)
Now it so happens that it is possible to transform away this variable gravitational constant and make it truly constant by a mathematical transformation called a conformal transformation. Basically, it amounts to reparameterizing space-time in such a way that the value of the gravitational constant becomes the same everywhere. (This transformation is described as switching from the Jordan frame to the Einstein frame.) However, this transformation is not without cost. As we transform away the coupling between the geometry of space-time and the scalar field, we end up introducing a variable coupling between the matter Lagrangian LM and the scalar field. The physics is now different! The geometry of space-time is now determined by a fixed coupling constant as in Einstein’s theory, but the trajectory of matter is no longer determined by geometry alone: there is an extra force, a so-called scalar force, acting on matter.
At first sight, this might seem weird. A simple mathematical transformation should not change the physics, or should it? Well… it does yet it doesn’t. If you fire a cannonball in Jordan-Brans-Dicke theory and calculate its trajectory, it will trace the same trajectory regardless which frame, the Jordan or the Einstein frame, you use to calculate it. It’s the interpretation of this trajectory that differs between the two frames. In the Jordan frame, the cannonball is said to follow a geodesic trajectory, but that geodesic, i.e., the curvature of spacetime, is affected by a varying gravitational constant. In the Einstein frame, the cannonball’s trajectory is not a geodesic anymore; the geodesic trajectory is determined by a fixed gravitational constant, but on top of that, an extra force deflects the cannonball.
One particular kind of scalar-tensor theory can be written in a form in which there is no variable gravitational constant and no coupling between the scalar field and matter either. This is the so-called “minimally coupled” scalar-tensor theory, in which the scalar field influences matter only indirectly: the scalar field has mass-energy, which gravitates, and this contributes to the overall gravitational field. Things can get tricky here: a scalar-tensor theory may be written in a form that does not look like a minimally coupled theory at all, yet it may be possible to transform it into one by an appropriate conformal transformation. However, this is not always the case: for instance, Jordan-Brans-Dicke theory cannot be transformed into a minimally coupled scalar-tensor theory this way, the two classes of theories are manifestly different.
When things get really interesting is when additional fields are present in a more complex theory, such as scalar-tensor-vector gravity. In that case, a conformal transformation can have surprising consequences on the coupling between these additional fields and the scalar field.
Just like after 9/11, the airspace of an entire region is closed today, grounding thousands of flights in the UK and Northern Europe.
Unlike on 9/11, this time around the closure is not the result of the panicked, knee-jerk reaction of clueless politicians and officials. It is the result of a volcanic eruption in Iceland:
The plume, clearly visible in this Eumetsat image, is a grave threat to aviation. 28 years ago, volcanic ash almost brought down a British Airways 747 full of passengers, and since then, numerous airliners have been damaged as they flew through similar plumes. Grounding all flights in the affected areas seems like a dramatic, but justified response to a very real threat.
Now the question is this: how long? According to news reports, the eruption shows no signs of abating. Will they keep flights grounded for days, even weeks if necessary?
Apollo 13, NASA’s “most successful failure”, was launched forty years ago today. One thing I didn’t know about the timing of the accident is the fact that the tank rupture occurred on the fifth stirring of the oxygen tank, which normally would have taken place 120 hours into the mission, when the lunar module was already on the Moon’s surface. Without the lunar module to serve as a lifeboat, the fate of the spacecraft would have been sealed. However, an unrelated sensor problem caused them to stir the tank more frequently, causing the accident to occur earlier.
Had the crew of Apollo 13 died in space, it has long been assumed that their spacecraft would have served as a frozen tomb for their bodies, orbiting the Sun. But now, some argue that the orbit of Apollo 13 was such that it would have returned to the Earth and burned up in the atmosphere just a few weeks later. I am not sure how you can really tell, with uncontrolled gas leaks, a tumbling spacecraft, and no precision radio-metric navigation data.
I’m back from a week-long trip to Hungary, visiting my Mom, relatives, and friends. Apart from the fact that the second half of my trip was made unnecessarily unpleasant by some cold bug I picked up on the flight from here to there, it was fun. But, it’s good to be home, even though, it seems, I came home in the middle of a heat wave. Yesterday, the heat almost killed me when I was looking for my car at Montreal airport (cars have the nasty habit of moving about when you leave them in large, public lots) while hauling my 60-pound suitcase. Today, it’s going to be even warmer. (No, we’re told, it’s not global warming… it’s the same El Niño weather that brought an unusually cold spring to parts of Europe.) I better check to see if our A/C still works after its winter hibernation.
Imagine solving one of the most profound outstanding problems in mathematics. Imagine living in poverty, in a cockroach-infested apartment in St. Petersburg, Russia. Imagine being awarded one of the world’s most prestigious prizes in science, the Millennium Prize of the Clay Mathematics Institute, which, incidentally, also comes with a cool $1,000,000.
And imagine turning it down. Which is precisely what reclusive Russian mathematician Grigory Perelman apparently did.
I don’t know what to think. Was it a matter of principle for him? Perhaps. But then, he could have indicated in advance that he wouldn’t accept the award, just as he refused to accept the Fields Medal a few years earlier. Why did he keep the world in suspense? Was it posturing? Or is he, hmmm, how can I put this politely, one fry short of a happy meal, to use a favorite phrase of mine from the television series Stargate SG-1?
An interesting anniversary today: 25 years ago, on March 15, 1985, the first ever .com domain name was registered, symbolics.com. The company, in addition to building their own brand of “Lisp Machine” computers, also happened to be selling the commercial version of the MACSYMA computer algebra software. The same software that, in the form of its open-source version, Maxima, continues to evolve thanks to a devoted team of developers… of which I happen to be one.
Alas, Symbolics is no longer, at least not the original company. A privately held company by the same name which obtained much of Symbolics’ assets still sells licenses of the old MACSYMA code.
Here’s yet another dramatic prediction by the Intergovernmental Panel on Climate Change (IPCC): that even a small temperature increase can lead to the loss of up to 40% of the Amazonian rain forest.
Except that it won’t. New research shows that there were no significant changes in the Amazon during the 2005 drought compared to previous years (also refuting previous speculation that drought might in fact help the rain forest grow). Like the prediction about Himalayan glaciers, the IPCC’s alarming statement was based solely on a non-peer reviewed report by the WWF (formerly known as the World Wildlife Fund, but no longer).
Defenders of the “scientific consensus” argue that small discrepancies notwithstanding, the findings of the IPCC are unassailable, the case for anthropogenic global warming is solid, and that the ones casting the first stone should be those who’d never leave a few innocent mistakes in a giant 1000-page report. If this was all there was to it, I should really keep my mouth shut; I’ve made more than my fair share of embarrassing mistakes in the past in stuff I wrote, and no doubt, I’ll make equally embarrassing mistakes in the future.
But these are not innocent mistakes, not small errors that only nitpickers care about, not even gross errors that can be attributed to carelessness. We’re not talking about a typo here, an omitted reference or erroneous formula there, an improperly drawn conclusion somewhere else. What we have here is the purposeful inclusion of non-peer reviewed material simply for its shock value. And not just in footnotes. This statement about the rain forests leads the section about Latin America, in the IPCC 2007 WG II Summary for Policymakers:
“By mid-century, increases in temperature and associated decreases in soil water are projected to lead to gradual replacement of tropical forest by savanna in eastern Amazonia.”
The body of the text that the summary refers to contains further alarming detail:
“Up to 40% of the Amazonian forests could react drastically to even a slight reduction in precipitation; this means that the tropical vegetation, hydrology and climate system in South America could change very rapidly to another steady state, not necessarily producing gradual changes between the current and the future situation (Rowell and Moore, 2000).”
The cited paper by Rowell and Moore is the non-peer reviewed report produced by the WWF, containing some dramatic language such as “the year the world caught fire”. Nonetheless, the authors’ prediction is not near as dire as the IPCC’s version, for which their paper is named as the sole source. Rowell and Moore only say that “up to 40% of the Brazilian forest is extremely sensitive to small reductions in the amount of rainfall.”
Don’t get me wrong, I firmly believe that the Amazonian rain forest is in serious trouble. You don’t need climate change for this… logging will do the trick nicely.
What I find inexplicable and unjustifiable is the IPCC’s decision not only to include such a striking prediction based solely on a non-peer reviewed source, but even embellish it. The IPCC’s report is supposed to be an objective assessment of the best science available, based upon which trillion dollar decisions will be made, affecting the world economy for generations to come. Instead, at least some sections of it look more like an activist’s pamphlet.
By undermining trust in the integrity of the science, the IPCC may be doing grave harm to the very cause it champions. The scientific evidence may be stronger in the future: the models will improve, and one day, will have real predictive power, the ability to reproduce accurately observed changes in the climate after a certain date using data available up to that date. At that time, we may yet find that the situation is even worse than we thought. Question is, will people still listen if the scientific community discredits itself now by crossing the line between science and activism?
You can tell that this picture was NOT made in Ottawa today because it’s presently 8 degrees Centigrade here, and the sun is still shining:
No, this video frame is from the French Riviera.
Every time I think about it, I feel compelled to think again: geologic changes are NOT supposed to happen in the blink of an eye, on a timescale of a mere 10,000 years. Yet at the very place where I live, Ottawa, a little over 10,000 years ago whales were swimming. How is that possible?
The answer is isostatic rebound. Up until about 13,000 years ago, this region was covered by the remnants of the last ice age, a layer of ice up to three kilometers thick. When this ice receded, the region was flooded by the sea, whales and all. This subsea was called the Champlain Sea, and may have been as much as 150 meters deep right here where I presently sit.
However, once the huge weight of the thick ice layer was gone, the Earth’s crust underneath rose up. This process is known as isostatic rebound. In a mere 3,000 years, the Champlain Sea was gone.
I suppose the same ice layer was also responsible for leveling the Ontario landscape such that this huge province, perhaps as large as France and Germany put together, has no point higher than 693 meters above sea level. Even tiny Hungary beats Ontario by more than a thousand feet!
I can see why people find geology fascinating.