Category: Science

New discoveries, the scientific method, and all matters relating to the scientific study of the physical world

Sleep and slime moulds

Since I spent the last fourteen hours sleeping, I don’t have much of interest to convey right now.

As a consolation, here is a time lapse video of slime moulds and fungus growing. I have always found slime moulds rather fascinating. They start of as single-celled, bacteria-eating organisms resembling amoebas. If two with matching mating types encounter one another, they can form a zygote. That, in turn, becomes a macroscopic organism with many nuclei, but no membranes between cells – an “interconnected network of protoplasmic strands.” Once this has eaten everything nearby, fruiting bodies form that disperse spores. These hatch into single-celled bacteria-eating eukaryotes once again.

One of the more odd and charming sections from the Wikipedia entry on slime moulds is this:

In 2006, researchers at the University of Southampton and the University of Kobe reported that they had built a six-legged robot whose movement was remotely controlled by a Physarum slime mold. The mold directed the robot into a dark corner most similar to its natural habitat.

It is disconcerting to consider that an entity consisting of an amalgamation of amoebas can apparently display something akin to preferences when put in control of a robot (though I think the ‘control’ just consisted of watching how the slime mould moved and copying it). This article has a picture of the robot.

In any case, I am hoping that my period of hibernation will reset my brain. During the last few days, it has sunken into something akin to – but nonetheless more profound than – the normal August lull which permeates Ottawa.

The future of plate tectonics

The PALEOMAP project has created some interesting projections of how the continents will be arranged in the distant future. Fifty million years out, Africa will have pushed into Europe, eliminating the Mediterranean. In 100 million years, all the continents will be drawing together. In 250 million years, only two landmasses will be left: a combination of Australia and Antarctica near the south pole and North and South America massed with Eusasia and Africa around a central sea.

The projections may prove entirely incorrect, but it is nonetheless remarkable to see the world thus transformed. It is a reminder of just how variable the world is, over long time horizons.

Listeria and the food system

The ongoing listeriosis outbreak in Canada is evidence of how broken out primary food system is, particularly insofar as meat is concerned. Producing billions of clones in packed conditions is dangerous enough, particularly if you simultaneously marinate them in growth hormones and antibiotics. Marrying that with a food system where every step of the production chain is concealed from consumers increases the risk.

What is most astonishing to me is the result of a poll conducted by The Globe and Mail on their website. Asked: “Has the listeriosis outbreak damaged your opinion of Maple Leaf products?” 38% of respondents said “no.” Perhaps this demonstrates the degree to which we are not aware of the shortfalls of our food system and food regulation, to the point where we accept this kind of occurrence as an inevitable consequence of food production.

More people should read Michael Pollan’s The Omnivore’s Dilemma. A safer, healthier food system is entirely possible. It will not, however, emerge while people are still happy to accept a dozen Canadian deaths (and counting) as part of the cost of having “pre-packaged meat products” available for purchase.

Stories of this kind sometimes makes me wonder whether personal vegetarianism is actually a selfish choice. Opting out of the system can be seen as an inferior alternative to agitating for change. After all, it was basically consumer demand that produced the emergence of organic and local food options. It is only when a mass market demand exists for healthy, safe, natural, and sustainable meat and seafood that systemic change could become possible.

More on food, health, and the environment:

Emily also wrote a post on this previously.

Bats and wind turbines

No form of electrical generation is entirely without unwanted impacts upon plants, animals, and the natural environment. Even the most environmentally appealing options (like solar, wind, and tidal power) have drawbacks. While they are minimal in comparison to the dire consequences of coal, natural gas, or nuclear power, they are real and ought to be acknowledged.

One unfortunate consequence of using wind turbines has recently come to light: the pressure drop near the blades kills bats. This is because the air inside the lungs expands in a low-pressure environment, causing the capillaries surrounding the air chambers to burst.

In the grand scheme of things, bat and bird fatalities produced by strikes and near-strikes on wind turbines are probably not a massive ecological cost. Nonetheless, they demonstrate how challenging it is to operate an industrial, technological society in a manner that is at least somewhat environmentally benign.

LHC activation

The hardware commissioning of the Large Hadron Collider (LHC) can be monitored on this website. Things are coming together fairly quickly now. The first particle beam injections took place on August 8th. On September 10th, the first full beam circulation will occur. On October 21st, the first high energy collissions should occur.

It seems likely that the collider will soon produce evidence of the Higgs Boson, and perhaps Hawking Radiation as well. Very exciting times to be watching physics, these.

[Update: 24 September 2008] Because of an overheated connection which caused a helium leak, it looks like the LHC will be out of commission until April 2009, at least. That is fairly understandable given the complexity of the machine, but it is still disappointing that we will have longer to wait for results.

Oil production and energy return on investment (EROI)

This chart demonstrates one characteristic of a changing energy return on investment (EROI). This is the ratio between how much energy is takes you to produce or acquire an energy source (such as oil, natural gas, biofuel, or hydrogen) and the amount of energy contained within it. This graph relates to a hypothetical oil field that is consistently able to produce 100,000 barrels per day of oil. On the left hand side, the EROI is 100:1. This means that you get 100 units of usable energy for every 1 unit you invest in extraction. This ratio is comparable to some of the best oilfields in Kuwait, where you just need to drill a hole and oil will gush out. On the right, the EROI falls towards 1:1. More and more of the barrels of output (or an equivalent energy source) must be used to extract the oil. By the end, there is no net energy production.

There are a few reasons for which this is important:

  1. It shows that even when the gross output of an oil field is stable, its value can fall off precipitously as the energy cost of extraction rises. This happens as you need to use more and more novel technologies and more and more capital to access the oil.
  2. EROI has a huge impact on the viability of alternative energy sources. If the ratio for biofuels is only 5:1 or 2:1, that means that enormously more energy must be devoted to producing the same quantity of fuel as was once available in Kuwait at 100:1.
  3. The combination of oil field depletion and worsening EROI can cause a faster dropoff in production than either factor taken in isolation.

One caveat should be mentioned in closing. There are situations in which an EROI of less than 1:1 is acceptable. Specifically, this is when the final product must have valuable special characteristics. This is true of exotic fuels like, say, sirloin steaks. Each one contains far fewer calories than it took to produce, but that is still economically acceptable due to the premium attached to the calories in the final product. While EROI ratios below 1:1 are acceptable in niche areas, they can never be the energy basis of an entire economy.

Defining science

The other day, Tristan and I were trying to ‘science’ and it became evident that the term has a stack of meanings. Those at the top arguably have the most day-to-day relevance, whereas those at the bottom are arguably more fundamental to the nature of science:

  • At the highest level, science consists of the people and institutions generally considered to be undertaking scientific work. This includes today’s physicists, chemists, biologists, and so forth. In an earlier era, it would have included alchemists. It also includes universities, research centres, funding bodies, and the like.
  • At the next level, science consists of a collection of theories that explain aspects of the world. Contemporary examples include special relativity, quantum mechanics, and the germ theory of disease. Kuhn’s Structure of Scientific Revolutions is an enlightening text largely about how these emerge and change.
  • At the next level, science is a set of key beliefs. Basically, these are that the universe operates in a manner that is consistent and comprehensible. In addition, it is at least theoretically possible to come to understand its workings through observation – using the mechanism of formulating and evaluating hypotheses.

The first two are very much affected by general trends in society and thought. The third is essentially assumed in the way through which our minds access the world. While we certainly cannot always understand the causal relationships involved (and random chance may always play a role that makes complete solution impossible), our mode of thinking fundamentally requires the assumption that things cause other things according to certain rules and that in the same conditions the same rules hold. We may never be able to track the course a hurricane will follow (or the hallucination a brain will have) on the basis of what atoms were where beforehand and what laws apply to them. Even so, a basic assumption of science is that such things are theoretically knowable, within the limitations created by random chance.

When it comes to the universe as a whole. it is quite possible that the collection of governing laws exceeds the human capacity to understand and/or discover. That becomes especially plausible if we accept the possibility that ours is just one of several universes, or that it is itself embedded in something far more complex.

Previous posts about the philosophy of science:

Debating the future of energy

The Economist is holding a debate in the style of the Oxford Union debating society (which I never joined while there due to the excessive cost). The topic is: “We can solve our energy problems with existing technologies today, without the need for breakthrough innovations.” This certainly seems to be the emerging wisdom among those who have looked seriously and comprehensively at the problems of energy and climate change. That’s not to say that technological improvements in things like batteries and photovoltaic cells would be useful, it is simply to assert that ‘breakthrough’ new technologies are not required, though they may well help.

The debate should be an interesting one to observe. The opening statements are from Joseph Romm – whose book I discussed earlier – and Peter Meisen.

Climate change, deforestation, and the deep sea

A while ago, there was an excellent question posted as a comment. The Stern Review and other sources say that the world can absorb about five billion tonnes of carbon dioxide equivalent per year. If emissions are above that, atmospheric concentrations rise. If they are below that, they fall. Does that mean that, in the absence of human activity, concentrations would be falling, year-on-year? Are our first five gigatonnes of emissions stabilizing?

To answer this, you need to remember that there are two big kinds of carbon sinks out there. The first is embodied in forests, but consists of all biomass. A world where all the forests of North America and Europe were intact would have less carbon dioxide in the air because more would be in wood, leaves, etc. That being said, for any level of forest cover and atmospheric greenhouse gas, the biosphere will eventually reach an equilibrium point where it emits as much carbon dioxide (from decaying plants, etc) as it absorbs from the air. The biosphere is thus more like a cushion than like an eternal allowance.

The other kind of sink consists primarily of the deep sea. It’s like a great big sponge that absorbs carbon dioxide. At present, it can absorb about five billion tonnes of carbon dioxide equivalent per year (the source of the Stern number). Like a sponge, however, it can only carry on absorbing for some time. As the deep sea becomes saturated with carbon dioxide, a higher and higher proportion of what we emit will remain in the atmosphere causing climate change.

In the long run, then, we don’t have a perpetual allowance of five gigatonnes per year. We have some big sinks that can absorb about that much at present. We need to rapidly cut human emissions below this level. Then, over a longer period of time, we will need to phase them down to virtually nothing. Otherwise, we will always have to contend with rising atmospheric concentrations of greenhouse gasses and the environmental consequences thereof.