The “Axis of Evil” in Astrophysics

The European Space Agency’s image illustrating two things that seem to falsify the cosmological principle. (click for credit)

A couple of days ago, I had a fun conversation with a student regarding astrophysics. He seemed very well-informed on the subject, so I begin using some physics “slang” to help move the conversation along. The student picked up on most of the references, but then we began discussing the cosmological principle, which is an assumption upon which the Big Bang model (and many other models of the universe) depends. It essentially states:

Viewed on a large enough scale, the properties of the universe are the same no matter where you are

The student was aware that most observations have never supported the cosmological principle, but he brought up the Cosmic Microwave Background (CMB), which he seemed to think supports it. I countered by mentioning the “Axis of Evil,” and he seemed to think I was joking. I was surprised that he didn’t get the reference, so I explained it to him. He was shocked that he hadn’t heard of it before, so he suggested that I write a blog post about it.

To understand the “Axis of Evil,” you first have to understand the CMB. When astrophysicists were working on the Big Bang model of the universe, which essentially says that the universe “exploded” into being from nothing, they realized that such an “explosion” would leave behind a signature: microwaves that appear from everywhere in the universe. The predicted details of these microwaves varied from paper to paper, but regardless of the details, everyone agreed that if the Big Bang happened, there should be a “background” of microwaves found everywhere in the universe. That’s what became known as the CMB.

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Does Anybody Really Know How Hot It Is?

Comparison of raw temperature data to the adjusted data for seven stations in New Zealand
(Figure 6.15 from the study being discussed)

Over the past few years, I have written about problems with the data related to global temperature measurements (see here and here). It is very difficult to get a handle on how the planet’s temperature has changed over the past century or so, because the only long-term data we have come from thermometers that are placed at various spots throughout the world. Since 1979, we have much more accurate global temperature data, which come from satellite measurements. However, those satellite measurements are not consistent with the thermometer measurements.

This is an important issue, because climate models (which make projections about future temperatures based on different emission scenarios) are “calibrated” against the known temperature data in an effort to make them more realistic. Since the satellite data have only been collected since 1979, they are rarely used. Instead, the longer temperature record (based on thermometers) is generally preferred. The two commonly-used thermometer records are GISS TEMP (maintained by NASA) and HadCrut4 (maintained by the University of East Anglia and the UK Met Office). Those two data sets are in good agreement with one another, but once again they do not agree with the satellite data.

Are these thermometer data reliable? Based on the PhD thesis of John D. McLean at James Cook University, the answer is “no.” He did what he claims is the first audit of the reliability of the Hadcrut4 data, and he has found 25 areas of concern. I will discuss only three. First, he finds many instances of anomalous data. One station in Colombia, for example, reports that the 1978 average monthly temperatures in April, June, and July were 81.5 oC, 83.4 oC, and 83.4 oC. In case you aren’t familiar with the Celsius temperature scale, that’s about 180 oF. Given that the highest temperature ever recorded on earth was 134 oF, it’s safe to say that the report from Colombia is simply wrong. He lists many other examples of anomalous data that cannot possibly be correct.

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Wind Farms Warm the Planet

A portion of the Gansu Wind Farm in China. It is the largest wind farm in the world. (click for credit)

More than five years ago, I wrote about a study that indicates wind turbines aren’t as “green” as many think. Indeed, it has been estimated that they are responsible for slaughtering more than half a million birds and nearly a million bats each year in the U.S. alone. A new study indicates another unforeseen consequence of wind farms: they actually warm their local area, which ends up warming the planet, at least a bit.

This isn’t a new suggestion. In fact, this recent study is partly a follow-up of a study that was published 14 years ago. In that study, the authors used a fairly simple physical model to indicate that by changing the way air is mixed near the surface of the earth, wind farms increase the temperature in their local area and, in turn, the entire planet. This new study uses a more sophisticated mathematical model, but it also compares the model’s results to warming that has actually been observed and measured near wind farms.

The authors show that their model reproduces the observed warming fairly well, so they use that model to make some estimates. They estimate that if all of the United States’ electrical needs are met with wind power, the wind farms would warm the continental U.S. by 0.24 degrees Celsius. The authors are quick to point out that this is much less than the warming that is supposed to occur as a result of the carbon dioxide produced by coal and gas power. However, it is clearly more than was expected and is at least ten times larger than any warming expected to be produced by meeting the needs of the country with solar power.

Of course, all of these models are far from realistic, because we are ignorant about so much when it comes to the earth’s climate and how various factors affect it. As a result, I take all of these numbers with a grain of salt. The actual fact is that we don’t know the warming that will occur as a result of any energy production source, including coal and gas. However, just as the science behind carbon dioxide trapping heat in the atmosphere is solid, the science behind this paper is solid. The authors demonstrate quite clearly that based on well-known physics, wind farms do warm their local area, and the observational studies they reference and use in their analysis confirm that this warming does, indeed, happen.

So what’s the bottom line? The most important one is the one I brought up in my five-year-old post about wind farms. The environmental effects of energy production aren’t as simple as people make them out to be. Every means of energy production will affect our planet in some way, and unfortunately, in the effort to produce “green” energy, this fact has been overlooked. If we are really interested in caring for our planet, we should not buy into a certain means of energy production (or a certain means of transportation) just because someone has decided it is “green.” Otherwise, we might be replacing a bad system with a worse one!

Directed Evolution Wins Nobel Prize

From left to right: Dr. Frances Arnold, Sir Gregory Winter, Dr. George Smith
(Credits:Beavercheme2, Aga Machaj, Univ. Missouri-Columbia)

Yesterday, the Royal Swedish Academy of Sciences announced that the Nobel Prize in chemistry will be shared among three scientists who all used directed evolution to engineer proteins that solve problems. A reader who saw a news story about the announcement asked me to explain what “directed evolution” means, and I am happy to oblige. In directed evolution, scientists use the concepts of variation and selection to take a molecule that already exists in nature and adapt it to do something that they want it to do. Using a concrete example that comes from the research of Dr. Frances Arnold (one of the recipients) is probably the best way to explain the process.

Dr. Arnold’s lab started with a naturally-occurring enzyme charmingly named P450 BM3. Enzymes speed up specific chemical reactions, and P450 BM3 speeds up the reaction in which an oxygen atom is inserted between a carbon atom and a hydrogen atom in a fatty acid molecule. This is an important step in the process by which a living organism breaks down fatty acid molecules. Dr. Arnold’s lab was interested in doing the same kind of reaction, but on a different type of organic molecule: a small alkane. The enzyme P450 BM3 couldn’t initially do that. However, it could weakly speed up that reaction on large alkanes.

Since the enzyme could at least do that, Dr. Arnold thought that she could “tweak” it until it did exactly what she wanted it to do. However, enzymes are absurdly complicated molecules, and human science isn’t very good at making or understanding them. So she decided to let better organic chemists (bacteria) do the heavy lifting. Her lab took the gene that tells bacteria how to make P450 BM3 and subjected it to mutations. They then saw whether or not the resulting enzyme made by bacteria was any closer to being able to do what they wanted it to do. Maybe it did a better job speeding up the reaction on a large alkane, or maybe it was able to speed up the reaction on a shorter alkane. If that was the case, they saved that gene and allowed it to mutate more, seeing if any more progress could be made. If not, they threw it away and tried again.

This is why the process is called “directed evolution.” Dr. Arnold’s lab induced mutations (which are a source of genetic change in organisms) and then selected any enzyme that ended up being better at what they wanted it to do. With enough of those steps, they were able to get what they wanted: an enzyme that inserted an oxygen atom between a carbon atom and a hydrogen atom in a small alkane. In the end, the process had changed just over 2% of the molecule, but that was enough to change it from an enzyme that acted on fatty acids to one that acted on small alkanes.

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