Wednesday, March 29, 2006
The next big one
I haven't been blogging lately because I've been out of town. I'm currently in Sacramento, and although I'm briefly returning home tomorrow, but then I'll be away from home for the next couple of weeks. I'm envious of bloggers who can keep posting when they're travelling; I wish I could. Nevertheless, I'll try to post things here and there. Like this:
A friend of mine recently pointed me to an article in this month's National Geographic on earthquakes titled The Next Big One. You can read an excerpt of at the link. It looks to be a pretty nice article, and they certainly talk to some of the people at the cuttings edge of earthquake research (Mark Zoback, a geolophysicist at Stanford, Bill Ellsworth, a seismologist with the USGS, Bob Nadeau, a seismologist with Berkeley's Seismological Lab, and the venerable Kerry Sieh, an icon of earthquake-related geology from Cal Tech). My friend was kind enough to loan me her copy, and once I've read through it in detail I'll post my thoughts.
A friend of mine recently pointed me to an article in this month's National Geographic on earthquakes titled The Next Big One. You can read an excerpt of at the link. It looks to be a pretty nice article, and they certainly talk to some of the people at the cuttings edge of earthquake research (Mark Zoback, a geolophysicist at Stanford, Bill Ellsworth, a seismologist with the USGS, Bob Nadeau, a seismologist with Berkeley's Seismological Lab, and the venerable Kerry Sieh, an icon of earthquake-related geology from Cal Tech). My friend was kind enough to loan me her copy, and once I've read through it in detail I'll post my thoughts.
Thursday, March 23, 2006
BYU Professor will lecture on science & religion
I just saw this article in today's Deseret News. Professor J. Ward Moody from BYU's physics and astronomy department will be speaking on March 31.
Sounds like it will be an interesting lecture.
His 7 p.m. address, which will be in the Joseph Smith Building auditorium, is titled "Time in Scriptures and Science: A Conciliatory Key?" Moody's lecture will focus on the debate between science and religion on such topics as the Earth's creation. He will also discuss the possibility of reconciling the different time lines.
Admission is free and the public is welcome.
Sounds like it will be an interesting lecture.
Tuesday, March 21, 2006
On Shaky Ground
With the 100th anniversary of the 1906 San Francisco Earthquake approaching (Apr. 18), the latest issue of National Geographic magazine is largely devoted to that earthquake and earthquakes in general. The articles in the magazine detail how our understanding of earthquakes has increased since 1906 and the current strides being made by seismologists in predicting when and where earthquakes will occur. The issue includes a fold-out earthquake risk map of the world. The map also includes locations and information on the ten deadliest earthquakes and the 10 costliest earthquakes in the past 100 years. Amazingly, the 1906 San Francisco earthquake does not make either list, although the Loma Prieta earthquake (a.k.a. "World Series earthquake") is on the costliest list. If you are interested in historical earthquakes, then I would recommend this issue.
OK, enough free advertising for National Geographic. In addition to the earthquake resources listed in Western Geologist's previous post, the US Geological Survey has a real-time list of recent earthquakes with maps for both the US and the entire globe. They also have top ten lists, earthquake stats, earthquake trivia, and today in earthquake history. Jump on over and have a look around.
OK, enough free advertising for National Geographic. In addition to the earthquake resources listed in Western Geologist's previous post, the US Geological Survey has a real-time list of recent earthquakes with maps for both the US and the entire globe. They also have top ten lists, earthquake stats, earthquake trivia, and today in earthquake history. Jump on over and have a look around.
Thursday, March 16, 2006
The GISP2 ice core and the age of the earth
Jared at LDS Science Review has a great post about ice cores, and the reasons why those cores indicate the earth is more than a few thousand years old. In the comments on that post Rob Osborn claimed that the The Lost Squadron indicated that the GISP2 ice core, drilled in Greenland and recording ~110,000 years of snow accumulation according to conventional scientists, could only be a few thousand years old (a claim made by several young earth creationists including Michael Oard, Larry Vardiman, and Kent Hovind). In his original post Jared linked to a paper by Paul Seelyfrom the ASA that discussed the GISP2 ice cores, as well as reasons why YEC authors are wrong about the implications of the Lost Squadron. It's a great paper, and well worth reading. I want to spend a bit of time going over Seely's paper.
The GISP2 core
The GISP2 core was drilled through the Greenland Ice Sheet near its summit, and is more than 3000 m long. Similar to varves, there are seasonal variations recorded in the ice, and by counting these seasonal variations it's possible to date the core. The seasonal variations are determined using a variety of independent techniques.
Variations in ice morphology
In Greenland the sun only shines during the summer. This results in the formation of hoar, which is a coarse grained low-density type of snow. The snow in the winter is fine grained and high density. So one year is equivalent to one layer of hoar plus one layer of regular snow (there's probably a more technical term than "regular snow", but not being a glaciologist I don't know it). The upper portion GISP2 core has around 12000 of these pairs. These pairs aren't visible in the deeper portion of the core, because as older snow is buried by younger snow it is compacted, and eventually this compaction destroys the summer and winter types of ice crystals. Other techniques are required to date the older, deeper portions of the core.
Seasonal variations in dust
The wind in Greenland blows most strongly in the late winter and early spring, and at those times more dust is deposited over the snow. So one year of snow deposition is equal to one high dust and one low dust pair.
Dating of volcanic ash
Similar to more mundane dust, ash from volcanic eruptions can be spread over Greenland by wind. The ages of the eruptions can be determined using one or more of the techniques discussed here, and then those ages can be compared to ages from known eruptions.
Seasonal variations in electrical conductivity
Nitric acid is produced in the atmosphere during the summer, but not in the winter. The presence of this nitric acid makes the summer layers more electrically conductive than the winter layers. One year equals one high conductivity layer plus one low conductivity layer.
Seasonal variations in oxygen isotopes
Evaporation affects oxygen isotopic composition. Winter snow is isotopically lighter than summer snow. So one year of deposition is also equal to one isotopically light layer plus one isotopically heavy layer.
Other techniques
This link lists all of the techniques that were used to date the GISP2 core. They list several that Seely didn't discuss, and since I'm not familiar with them I'm not going to write about them at this point. I'll try to look up the references listed on that site at some point.
All of these independent techniques indicate that the GISP2 core is far older than 6-10,000 years, which is a serious problem for YECs.
The Lost Squadron
During World War II a squadron of P-38 fighters and B-17 bombers crash landed near the coast of Greenland. 50 years after that a group of people returned to the crash site and salvaged one of the planes, which was buried beneath 268 ft of ice. According to one of the salvagers there were also hundreds of layers in the ice. This caused some YECs to argue 1) that the 3000+ m of ice from the GISP2 site could have been deposited much more quickly than originally thought, and 2) the layers observed in the GISP2 core weren't necessarily due to seasonal variations – they might be due to shorter term warming and cooling cycles. There are a few reasons why those claims don't hold up.
The depth of ice – the amount of annual snowfall at the Lost Squadron site (near the coast) is much greater than the GISP2 site (far inland near the summit of the ice sheet). The annual snowfall at the Lost Squadron site is around 7 ft per year. So 268 ft of snow in 50 years isn't unusual for that site. The amount of annual snowfall at the GISP2 site is much lower (around 1 ft per year). Using the amount of snowfall accumulation at the Lost Squadron site to infer the rate of snow accumulation at the GISP2 site is wildly inappropriate. That would be like using the amount of rainfall on the west side of the Cascade Mountains in Oregon to make predications about the amount of annual rainfall in Arizona.
The layering from the Lost Squadron site -- The Lost Squadron site should contain at least 100 layers (50 years with 2 layers per year), so some number of layers should be expected at that site. More importantly, the glaciologists who study ice cores do not simply assume that all layers are due only to seasonal variations. Layers can be caused by nonseasonal events like melting, but those layers look quite different from the winter and summer layers. The summer layers are coarse grained, low density snow with many large air bubbles; the winter layers are finer grained and lower density, while the melt layers are glassy and almost bubble free. Here is a partial record of melt features in the GISP2 core. Clearly it is possible to distinguish summer, winter, and melt layers. If YECs want to refute the age of the GISP2 core they need to do more than to point out that the ice at the Lost Squadron site had a lot of layers. They need to 1) demonstrate that those layers have the same characteristics (ice morphologies) as the layers from the GISP2 site – in other words they need to show that the layers at the Lost Squadron site aren't melt layers, and 2) show that the Lost Squadron layers have the same variations in dust concentration, conductivity, etc., that is seen at the GISP2 site.
The GISP2 core
The GISP2 core was drilled through the Greenland Ice Sheet near its summit, and is more than 3000 m long. Similar to varves, there are seasonal variations recorded in the ice, and by counting these seasonal variations it's possible to date the core. The seasonal variations are determined using a variety of independent techniques.
Variations in ice morphology
In Greenland the sun only shines during the summer. This results in the formation of hoar, which is a coarse grained low-density type of snow. The snow in the winter is fine grained and high density. So one year is equivalent to one layer of hoar plus one layer of regular snow (there's probably a more technical term than "regular snow", but not being a glaciologist I don't know it). The upper portion GISP2 core has around 12000 of these pairs. These pairs aren't visible in the deeper portion of the core, because as older snow is buried by younger snow it is compacted, and eventually this compaction destroys the summer and winter types of ice crystals. Other techniques are required to date the older, deeper portions of the core.
Seasonal variations in dust
The wind in Greenland blows most strongly in the late winter and early spring, and at those times more dust is deposited over the snow. So one year of snow deposition is equal to one high dust and one low dust pair.
Dating of volcanic ash
Similar to more mundane dust, ash from volcanic eruptions can be spread over Greenland by wind. The ages of the eruptions can be determined using one or more of the techniques discussed here, and then those ages can be compared to ages from known eruptions.
Seasonal variations in electrical conductivity
Nitric acid is produced in the atmosphere during the summer, but not in the winter. The presence of this nitric acid makes the summer layers more electrically conductive than the winter layers. One year equals one high conductivity layer plus one low conductivity layer.
Seasonal variations in oxygen isotopes
Evaporation affects oxygen isotopic composition. Winter snow is isotopically lighter than summer snow. So one year of deposition is also equal to one isotopically light layer plus one isotopically heavy layer.
Other techniques
This link lists all of the techniques that were used to date the GISP2 core. They list several that Seely didn't discuss, and since I'm not familiar with them I'm not going to write about them at this point. I'll try to look up the references listed on that site at some point.
All of these independent techniques indicate that the GISP2 core is far older than 6-10,000 years, which is a serious problem for YECs.
The Lost Squadron
During World War II a squadron of P-38 fighters and B-17 bombers crash landed near the coast of Greenland. 50 years after that a group of people returned to the crash site and salvaged one of the planes, which was buried beneath 268 ft of ice. According to one of the salvagers there were also hundreds of layers in the ice. This caused some YECs to argue 1) that the 3000+ m of ice from the GISP2 site could have been deposited much more quickly than originally thought, and 2) the layers observed in the GISP2 core weren't necessarily due to seasonal variations – they might be due to shorter term warming and cooling cycles. There are a few reasons why those claims don't hold up.
The depth of ice – the amount of annual snowfall at the Lost Squadron site (near the coast) is much greater than the GISP2 site (far inland near the summit of the ice sheet). The annual snowfall at the Lost Squadron site is around 7 ft per year. So 268 ft of snow in 50 years isn't unusual for that site. The amount of annual snowfall at the GISP2 site is much lower (around 1 ft per year). Using the amount of snowfall accumulation at the Lost Squadron site to infer the rate of snow accumulation at the GISP2 site is wildly inappropriate. That would be like using the amount of rainfall on the west side of the Cascade Mountains in Oregon to make predications about the amount of annual rainfall in Arizona.
The layering from the Lost Squadron site -- The Lost Squadron site should contain at least 100 layers (50 years with 2 layers per year), so some number of layers should be expected at that site. More importantly, the glaciologists who study ice cores do not simply assume that all layers are due only to seasonal variations. Layers can be caused by nonseasonal events like melting, but those layers look quite different from the winter and summer layers. The summer layers are coarse grained, low density snow with many large air bubbles; the winter layers are finer grained and lower density, while the melt layers are glassy and almost bubble free. Here is a partial record of melt features in the GISP2 core. Clearly it is possible to distinguish summer, winter, and melt layers. If YECs want to refute the age of the GISP2 core they need to do more than to point out that the ice at the Lost Squadron site had a lot of layers. They need to 1) demonstrate that those layers have the same characteristics (ice morphologies) as the layers from the GISP2 site – in other words they need to show that the layers at the Lost Squadron site aren't melt layers, and 2) show that the Lost Squadron layers have the same variations in dust concentration, conductivity, etc., that is seen at the GISP2 site.
Wednesday, March 08, 2006
ID and the DI
I'm a lurker on the mailing list of the American Scientific Affiliation. I usually quite enjoy about half of the material I receive from that list (which I think is a pretty decent percentage). Ted Davis, a member of the faculty at Messiah College, recently posted a link to an article he wrote called "Intelligent Design on Trial." The article can be found here (the file is in PDF format).
It's one of the better articles on intelligent design I've read. I think that Davis is wrong on a few things. He argues that ID isn't the same thing as creationism (he's made this point on the ASA mailing list too), and I don't see how ID can be separated from classic creationism given how tightly the two are currently entwined. I think that with a lot of effort (and frankly with a lot more integrity than the Discovery Institute has currently displayed), ID could take on a life of its own.
I've read through Davis' essay a couple of times now, and I think it warrants a couple more. Here are a couple of passages that really caught my attention:
I really agree with this. If ID proponents really want to be taken seriously they need to present a coherent theory of ID. Currently the fellows of the Discovery Institute hold conflicting views – some are young earth creationists (e.g., Paul Nelson), while some accept almost all of conventional biological evolution (e.g., Michael Behe). I interpret this as an indication that ID is just a political movement – ID proponents can't agree on the science of ID, all they share is a nebulous conviction that there has to be something more than evolution. Moreover, rather than try to find evidence to support their convictions, they try to avoid expert scrutiny and spend their time trying to persuade politicians.
Davis also writes:
The appalling behavior of some Utah state senators and ID advocates in Dover reinforces Davis' point.
Davis ends his essay with a quote from Judge Jones' Kitzmiller opinion:
I am so heartened by his comments about the Discovery Institute. Davis seems to be a fan of some form of ID, which is a position that I don't share. However, in my mind ID and the Discovery Institute are one and the same. If a new ID movement arises, I'll reevaluate my position.
It's one of the better articles on intelligent design I've read. I think that Davis is wrong on a few things. He argues that ID isn't the same thing as creationism (he's made this point on the ASA mailing list too), and I don't see how ID can be separated from classic creationism given how tightly the two are currently entwined. I think that with a lot of effort (and frankly with a lot more integrity than the Discovery Institute has currently displayed), ID could take on a life of its own.
I've read through Davis' essay a couple of times now, and I think it warrants a couple more. Here are a couple of passages that really caught my attention:
"Currently, the ID movement is, to use its own language, a "big tent" under whose sprawling canvas there is plenty of room for differences about theological and biblical issues related to the age of the earth. A full public discussion of these issues would not disturb most of the intellectual leaders of the movement. But it would alienate the many grassroots creationists who support ID—and who provide it with much of its political support. So while ID is not creationism, creationism remains the elephant in the room. Judge Jones evidently smelled the elephant quite distinctly.
At this point, there simply is no ID "theory" to teach—or even to practice in the laboratory, let alone to place at the center of a new scientific paradigm. ID currently consists only of an interesting philosophical critique of the explanatory efficacy of Darwinian evolution, combined with an appeal for scientists to add "design" to the set of explanatory principles they employ in biology and other sciences."
I really agree with this. If ID proponents really want to be taken seriously they need to present a coherent theory of ID. Currently the fellows of the Discovery Institute hold conflicting views – some are young earth creationists (e.g., Paul Nelson), while some accept almost all of conventional biological evolution (e.g., Michael Behe). I interpret this as an indication that ID is just a political movement – ID proponents can't agree on the science of ID, all they share is a nebulous conviction that there has to be something more than evolution. Moreover, rather than try to find evidence to support their convictions, they try to avoid expert scrutiny and spend their time trying to persuade politicians.
Davis also writes:
"Ironically, some of the biggest insults have been directed by Christians against those Christian scientists and other thinkers who do not find ID sufficiently persuasive. Years ago, for example, Johnson referred to them as "mushy accommodationists."
I doubt that the rhetoric will cool anytime soon, despite the fact that the Dover case is now over. Certainly, in the wake of the judge's decision, ID advocates promised to continue the fight across the land.
But the decision itself is hard, for me at least, to dispute. Given the evidence, the judge really had no choice but to rule that the school board tried to inject a reference to ID for religious reasons, and that it had no clear secular purpose for doing so. "The evidence at trial demonstrates that ID is nothing less than the progeny of creationism," the Judge wrote, and in this particular instance I can't blame him. As a result "it is unconstitutional to teach ID as an alternative to evolution in a public school science classroom."
The appalling behavior of some Utah state senators and ID advocates in Dover reinforces Davis' point.
Davis ends his essay with a quote from Judge Jones' Kitzmiller opinion:
""Those who disagree with our holding" Jones wrote near the end of his opinion, "will likely mark it as the product of an activist judge." I make no such accusation, but the Discovery Institute did not hesitate. Hardly had the decision been issued than John West, a politics professor at Seattle Pacific University who is also a long-time fellow of the institute, offered the following response on the institute's webpage www.discovery.org:
"Judge Jones found that the Dover board violated the Establishment Clause because it acted from religious motives. That should have been the end of the case. Instead, Judge Jones got on his soapbox to offer his own views of science, religion, and evolution. He makes it clear that he wants his place in history as the judge who issued a definitive decision about intelligent design. This is an activist judge who has delusions of grandeur."
Someone may be deluded here, but I doubt it is the judge."
I am so heartened by his comments about the Discovery Institute. Davis seems to be a fan of some form of ID, which is a position that I don't share. However, in my mind ID and the Discovery Institute are one and the same. If a new ID movement arises, I'll reevaluate my position.
Sunday, March 05, 2006
Accelerated Christian Education
Accelerated Christian Education (ACE) is an organization that makes materials for home schoolers and private schools to use. They must be doing quite well at it because they have a facility in Texas worth $20 million (and they have more facilities in Florida, where their headquarters is). I found out about them in an article from the Dallas Morning News (hat tip to this blog).
A mom who sent her son to a private school contacted the author of the Dallas Morning News article:
After reading that, I'm sure you can guess what their position on evolution is:
I've heard some members of the Christian community complain that faith is under attack in colleges and universities. People who use ACE materials shouldn't be surprised if their kids' faith is hurt when they go to college. It won't be due to any sort of attack from their professors, it will be because the ACE materials provided them with such a weak foundation for their faith. I think that some parents like that are motivated by a desire to protect their kids from what they view as a corrupting influence in the non-Christian world – they want to shield their kids' faith (any readers should feel free to chime in with their views). I can appreciate that motivation without sharing it. However, I don't see how you can protect your kids by providing them with inaccurate information about the world. You'll just leave them unprepared to deal with the larger world.
A mom who sent her son to a private school contacted the author of the Dallas Morning News article:
A concerned mom called my attention to the politically loaded lessons. She was troubled by some of the Texas history worksheets her son was bringing home.
That's where he had learned the definitions of liberal ("referring to philosophy not supported by Scripture") and conservative ("dedicated to the preserving of Scriptural principles").
The mom said she sent him to a small Christian school for more personal attention. But she didn't know that would mean such lopsided political ideology.
After reading that, I'm sure you can guess what their position on evolution is:
The textbook goes on to set up a false choice between evolution and God. "Both cannot be right. Is it logical to trust Darwin or God? It is odd that whenever given the choice of accepting the Bible or some man-written book, the liberals always reject the Bible and accept the other book."
I've heard some members of the Christian community complain that faith is under attack in colleges and universities. People who use ACE materials shouldn't be surprised if their kids' faith is hurt when they go to college. It won't be due to any sort of attack from their professors, it will be because the ACE materials provided them with such a weak foundation for their faith. I think that some parents like that are motivated by a desire to protect their kids from what they view as a corrupting influence in the non-Christian world – they want to shield their kids' faith (any readers should feel free to chime in with their views). I can appreciate that motivation without sharing it. However, I don't see how you can protect your kids by providing them with inaccurate information about the world. You'll just leave them unprepared to deal with the larger world.
Saturday, March 04, 2006
Earthquakes in the Bay Area
The Association of Bay Area Governments (ABAG) has a lot of really nice resources dealing with earthquake, and other natural hazard, risks in the Bay Area of California. My favorite is their interactive shake maps. Shake maps predict the intensity of ground shaking during an earthquake. ABAG has shake maps for a variety of different earthquakes, including another quake like the 1906 San Francisco earthquake, a quake on the Hayward fault, or a quake on the Calaveras fault. The really nice thing about the shake maps is that they're searchable by address, so if you're a Bay Area resident you can get some idea about how the hazards predicted for your town during an earthquake. It's an easy way to spend a couple of hours (for me at least, but then my wife calls me a nerd).
Here's a map of predicted shaking intensity in San Francisco for an event like the 1906 earthquake:
They've also got maps of liquefaction potential, and very importantly, how to make your home safer. The USGS has a publication called Putting Down Roots in Earthquake Country. It's written for people in the Bay Area, but it's got a lot of useful information for anyone living in a seismically active area. Actually, I think people in general would benefit from reading through the section on getting prepared for a disaster. A lot of the information is relevant for hazards like tornados or hurricanes.
Here's a map of predicted shaking intensity in San Francisco for an event like the 1906 earthquake:
They've also got maps of liquefaction potential, and very importantly, how to make your home safer. The USGS has a publication called Putting Down Roots in Earthquake Country. It's written for people in the Bay Area, but it's got a lot of useful information for anyone living in a seismically active area. Actually, I think people in general would benefit from reading through the section on getting prepared for a disaster. A lot of the information is relevant for hazards like tornados or hurricanes.
