Between 6 and 25 km thick, the Earth’s crust is an excruciatingly thin skin on a 6400 km globe. Yet even drilling to the bottom of the crust would require a remarkable feat of engineering. Some geologists want to try.
NPR’s Science Friday interviews Damon Teagle, one of the architects of the project. They want to drill in the ocean because oceanic crust is thinner than continental crust (on the other hand, it’s denser too, which is why it subducts).
Using different types of chocolate covered candy, they also have this wonderful video of the basalts, sheeted dykes and gabbros that make up the crust.
Our trip was not without difficulties, however. The group learned a bit more about self-regulation, governance and the balance of powers, as a consequence of “The Great Brownie Incident,” and the, “P.E. Fiasco.”
We were also fairly well cut off from the “cloud”: no internet, and you could only get cell reception if you were standing in the middle of the road in just the right spot in front of Cabin #3.
But more on these later. I have some sleep to catch up on.
This wonderful, impressionistic image shows representatives of the three domains of life and large viruses, the proposed fourth.
This figure represents the living species in the four small pictures according to the current classification of organisms: eukaryotes (represented by yellow cell), bacteria (represented by green cell), Archaea (represented by blue cell) and viruses (represented by magenta colored Mimivirus).
— Boyer et al. (2010): Boyer M, Madoui M-A, Gimenez G, La Scola B, Raoult D (2010) Phylogenetic and Phyletic Studies of Informational Genes in Genomes Highlight Existence of a 4th Domain of Life Including Giant Viruses. PLoS ONE 5(12): e15530. doi:10.1371/journal.pone.0015530
Carl Zimmer has an excellent piece in Discover Magazine that summarizes the research, and sets out the new tree of life. Particularly important, is the fact that viruses can transfer genes with each other. The other domains tend to mix their genes during reproduction.
Expanding globe of debris from the explosion of Tycho's Star. Tycho Brahe observed the star as it went supernova about 540 years ago. The red is the debris, the stardust, created by the explosion. Image from NASA.
We could have been talking about the nuclear meltdowns in Japan, but I’m not sure. Our conversations tend to wander. I remember trying to explain where the carbon atoms, that are so essential for life, came from. It’s been a while since we saw this topic, so I figured it wouldn’t hurt to go it over again. And then I found this wonderful image of the Tycho supernova from the Chandra space telescope. Supernovas are where the heaviest atoms are formed.
In the beginning … the big bang created just the smallest elements, hydrogen and helium. But even these tiny things have gravity, so they pull each other together until there’s so much stuff that the pressure at the center of the clump is enough to fuse hydrogen atoms together.
Now fusion is easy to confuse with chemical bonding that occurs around us every day. After all, the hydrogen in the atmosphere is usually in the form of H2, which is two hydrogen atoms bonding together by shared electrons.
With fusion, on the other hand, the single protons that make up the nuclei of the hydrogen atoms are pushed together to create a bigger atom, helium. I say pushed together, because it takes a lot of pressure to fuse atomic nuclei. And it also releases a lot of energy. Notice all that heat and radiation that comes from the Sun? All that energy was created by the fusion of hydrogen atoms; the smallest element, hydrogen, fuels the stars.
Fusion of two hydrogen atoms to create helium, compared the chemical bonding of hydrogen atoms to produce hydrogen gas (H2). The nutrons are left out for clarity.
The huge amounts of energy released by fusion makes fusion power one of the holy grails of nuclear energy research. If we were able to create and control self-sustaining fusion reactions, just like what happens in the Sun, we would have a source of tremendous energy. There is a lot of research in this area. Some people have figured out how to build fusion reactors in their basements, but these use a lot more energy than they produce so they’re not very useful as a power plant (Barth, 2010). The ITER reactor, currently being built in France, aims to be the first to produce more electricity than it uses.
Now back to the stars. Hydrogen atoms fuse to form helium, but it takes a lot more pressure to create larger atoms: carbon has six protons, nitrogen seven, and oxygen eight. These elements are essential for life (as we know it). The only time stellar forces are great enough to produce these are when stars explode; an exploding star is said to have gone nova. Bigger atoms, like iron (26 protons), gold (79 protons), and uranium (92 protons) need even greater forces, forces that only occur when the largest stars go supernova.
DNA. (from Wikipedia)
So if these elements are only produced in novae and supernovae, how did they get to Earth? How did they get into your DNA?
Well when stars explode, a lot of these newly formed elements are blasted off into space. It’s a sort of cosmic dust. We could even call it stardust. It’s matter, just like the hydrogen and helium from the big bang, only bigger, which means they have more mass, which means they have more gravity.
Formation of the solar system (model).
The gravity pulls the stardust together with the hydrogen and helium sill floating around in space (there’s a lot of it), to form new stars, and, now that there are the larger elements to create them, rocks, asteroids, and planets.
So, if you think about it, some stars needed to have been formed, lived their lives (which consists of fusing hydrogen atoms until they run out), and exploded to create the matter that makes up the planets in our solar system and the calcium in our bones, the sodium in our blood, and the carbon in our DNA.
Notes:
1. Lots of information about Tycho’s Star on SolStation.com.
Last month I observed that the girls in my class were blogging a lot more than the boys. It’s still true, and now there’s an informative, if somewhat hyperbolic, article by Aileen Lee that asserts that the blooming of social media websites is driven, primarily, by women.
I’m always a bit leery about articles like this one. There are lots of statistics, a few anecdotes, and a brief reference back to some scientific research (Dunbar numbers), but the overly excited language coming from a venture capitalist is enough to remind me of the irrational exuberance of the dot-com bubble.
The writing is so over-the-top, that I’m truly surprised that there isn’t a single exclamation point in the entire article! Although, based on Ms. Lee’s first words in the comments section, this might be due to the herculean efforts of a good editor.
My antipathy might also be due to my irrational, visceral distaste of the language of business and commerce, which is so geared toward breaking people into faceless demographic groups to be marketed to that it verges on being dehumanizing. I suspect my feelings are truly irrational because I’ve seen scientists do similar parsing of demographic statistics and have had no trouble; although, perhaps, I may have been a little more empathic because the scientists were looking at issues of vulnerability to disease, infant mortality, and the like.
However, since the article’s anecdotes correlate with my own anecdotes, I find it hard to disagree with the underlying premise: women are more inclined than men to make and nurture social connections so they are a key demographic in understanding the future of the internet.
It’s also a reminder that the social atomization typified by the dominance of the nuclear family at the expense of extended family, is now being ameliorated by social networking, which suggests some interesting social and cultural changes in a, possibly, more matrifocal future.
With the different outcomes of the protests in Tunisia and Egypt compared to Libya and Syria (and Bahrain), it’s important to recognize the courage of the protesters out there on the streets. It’s not really courage if there is nothing to risk. These men and women are risking everything.
Just like the lonely man who stood in front of a line of tanks during the Tiananmen Square protests in 1989. No one knows what happened to him.
About midday, as a column of tanks slowly moves along Chang’an Boulevard toward Tiananmen Square, an unarmed young man carrying shopping bags suddenly steps out in front of the tanks. Instead of running over him, the first tank tries to go around, but the young man steps in front of it again. They repeat this maneuver several more times before the tank stops and turns off its motor. The young man climbs on top of the tank and speaks to the driver before jumping back down again. Soon, the young man is whisked to the side of the road by an unidentified group of people and disappears into the crowd.
To this day, who he was and what became of him remains a mystery.
What does it take to show such courage? We’ve talked about how your situation in life, like poverty, can affect the ethical choices you make. We’ve also seen how different social and demographic conditions can force countries toward revolutions.
So it’s worth taking a moment to think about the protesters. And about ourselves. What do we value so much that it would overcome our fear to risk our lives?
View over the Mississippi River from the scenic outlook in the Trail of Tears State Park. The outlook juts out over rocky bluffs, which allows you to see the flood plain across the river.
Driving through Missouri last week, I stopped at the Trail of Tears State Park, which may be an excellent place to study the post-colonial history of Native Americans (perhaps as part of our civil rights discussions), and observed the Mississippi River and its flood plain before it becomes engorged at its confluence with the Ohio River.
In 1830, President Andrew Jackson passed the Indian Removal Act, which called for the removal of American Indians living east of the Mississippi River to relocate west of the Mississippi River. …
While some of the Cherokees left on their own, more than 16,000 were forced out against their will. In winter 1838-39, an endless procession of wagons, horsemen and people on foot traveled 800 miles west to Indian Territory. Others traveled by boat along river routes. Most of the Cherokee detachments made their way through Cape Girardeau County, home of Trail of Tears State Park. While there, the Indians endured brutal conditions; they dealt with rain, snow, freezing cold, hunger and disease. Floating ice stopped the attempted Mississippi River crossing, so the detachments had to set up camps on both sides of the river. It is estimated that over 4,000 Cherokees lost their lives on the march, nearly a fifth of the population.
Taking a break on the Nature Walk behind the park's museum.
There’s a short, 1 km nature walk behind the building that was nice on a beautiful, sunny day in early spring. Warm, with the trees just barely beginning to bud you can get a feel for the ridge-and-valley topography of the park, which is in stark contrast to the flat floodplain of the Mississippi on the other side of the river. The park’s roads weave up and down the ridges, and I wished I’d had my bike with me.
Barge going downstream on the Mississippi River, past the river-side campground.
This early in the year (mid-March) most of the campgrounds in the interior of the park seem to be closed, but there is one down on a beach of the Mississippi River that was empty but open. This one has electrical hookups which is not a bad thing if you have the place all to yourself.
The scenic outlook is a wooden platform that juts out through the trees so you can see across the Mississippi to the flat floodplain and farmland beyond. Sitting on a cliff of sedimentary rock (it looked like limestone from a distance), the outlook is high enough that you can just make out the shapes of old meander bends and ox-bow lakes.
It’s a small park, probably worth a visit for the museum, and the outlook is nice, but probably not somewhere you’ll want to spend the night unless some of the upland campgrounds are open.
The museum’s focus on the relocation of the Cherokee would be a nice followup to the pre-Columbian focus of the Chucalissa Museum in Memphis.
Cape Girardeau River Wall.
If you’re looking at river processes, you’ll probably also want to stop in Cape Giradeau, which boasts a fromidable wall to protect the downtown from the Mississippi River’s spring floods.
This cute, little, true story of how a bunch of kids (they look like adolescents) living on rafts in a lake built their own soccer field (on rafts), and eventually created the Panyee Football Club, is actually an advertisement for the Thai Military Bank (TMB), but it’s quite inspirational nonetheless. The setting and videography are also superb.
