Archive for the ‘science’ Category
Mapping Behavior to Environment
About 1.5 million years ago, a large group of chimps were separated by a growing Congo river. The south side of the river had more abundant food sources than the north. The chimps on the abundant side are known today as bonobos, and they're very mellow. The women run things. They're neighborly, sharing territory with other bonobo groups. When tensions rise, they have sex instead of fighting. Chimps on the side with less abundance are known today as chimpanzees, and they're much more aggressive. They're very territorial, patrolling their borders in gangs, merciless in fighting, hierarchical and patriarchal. These behavior patterns map to their environments. In times and places of scarcity, competition is more intense. Strength and force become the rule, escalating violence. In abundance, a flat, cooperative society works fine. Violence within our communities is not our default. It's turbulence that emerges when people can't meet their needs. To maximize choice and minimize drama, work for community-wide abundance.
Three Bright Lights
Last night the sky over Washington, DC was unusually clear, so we had a spectacular view of three planets low in the pre-dawn east. Venus, Jupiter and Mars were all pointed toward the coming sunrise. It reminded me of one of the early geometry puzzles I sorted through while learning astronomy.
Venus orbits closer to the sun than we do. When we’re on the earth’s night side, it’s orbit is “behind” us. When we look up and out, we’re looking toward the orbits of the outer planets – Mars, Jupiter, Saturn, etc.
So it makes sense that we see the outer planets at night, when we face away from the sun; but how is it we can see them and the inner planet Venus *at the same time*?
If all the planets remained aligned and orbited in lockstep, then that would be an issue. But of course planets are at different parts of their orbits at different times, and this gives us windows when we can see them together.
My phone is most definitely not an astronomy camera. Please accept this simulated view from Stellarium, matching the exact time I saw it last night. The actual view was more impressive. Click on images to enlarge.
Celestia provides real-time simulated snapshots of our solar system. The view below is tilted sideways because you’re standing on a ball looking east. See the string of lights in the middle of the ocean? Hawaiian islands. Top center of Earth, the lights of the California coast. Look up, and what do you see? Same planets, same alignment.
Same image, with orbital paths added:
And an overhead view of the solar system at the same time:
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..and that’s how you see three planets, one inner, two outer, together on cool fall night.
Farmland Volcanoes
The mound you see here is Mole Hill in Northern Virginia, a bit over an hour away from Thomas Jefferson’s Monticello. 48 million years ago it was a volcano.
It has obviously worn down quite a bit since then, but the geological processes that gave it birth are still active. The Journal of Geophysical Research released results of a study that found parts of the mantle below this region are peeling off, weakening and destabilizing the crust above. This is what set off the 2011 earthquake that rattled Washington, DC and a good chunk of the Southeastern U.S.
The area sits close to the middle of the North American plate and because of that it’s normally stable. But the evidence revealed by the study suggests the mantle erosion is continuing and will eventually produce more earthquakes. No timetable on that – it might not even happen in our lifetimes.
But the slow grind of plates and the interaction of mantle and crust will continue, and as sometimes happens in these things, can open up fissures that allow hot magma to rise to the surface – giving birth to a new volcano.
Scientific American summarizes the history of east coast volcanoes, presented as detective story that takes you through time and shifting landscapes.
http://www.scientificamerican.com/article/recent-east-coast-volcano/
There are two extinct volcanoes in Virginia. Mole Hill is one; Trimble Knob is the other.
Trimble Knob
https://en.wikipedia.org/wiki/Trimble_Knob
Drive-by video of Trimble Knob
https://www.youtube.com/watch?v=TQm8mvBXvPI
Overhead view of Trimble Knob
Physics for Curious Teenagers
[One of 50 articles written and published for Demand Media in 2013]
Physics is often an intimidating subject because it encompasses so much – it is the foundation for how everything else works. Our understanding is advanced and growing, but not yet complete. There are still holes, and this is where the excitement lies – exploring the unmapped territories, standing on the shoulders of giants and seeing farther than any have seen before. The easy parts have been mapped, and the hard parts beckon. Teens with the academic capacity for this subject can benefit from strong parental encouragement and support. STEM (Science, Technology, Engineering and Math) programs are proliferating, and physics provides a reliable foundation for these areas. Check your teen’s school to learn about local courses.
Particle Physics
The most fundamental questions have been asked for centuries. Where are we from? How did we get here? Physics is part of our pursuit for answers. By examining the most basic building blocks that everything is made of, we discern the properties of both matter and energy, and how matter is essentially a form of energy. Chemistry, organic chemistry and biochemistry, the basis for life, all originate in particle physics. It’s like the “CSI: Crime Scene Investigation” shows, but this is the detective work of reality – physics underlies a lot of criminal investigative work.
Fermilab, the U.S. Department of Energy’s powerhouse of particle physics, offers a solid list of books on physics for regular people, and the Carnegie Library in Pittsburgh offers a selection of engaging physics books for teens — such as the “Manga Guide to Physics” — that are accessible without being dumbed down.
Electromagnetism
Fundamental particles carry positive and negative electrical charges, and these charges regulate the interaction of matter. As the Encyclopedia Britannica notes, at the particle level electrical charge is so powerful that the absence of only one electron out of every billion molecules in two 70-kilogram (154-pound) persons standing two meters (two yards) apart would repel them with a 30,000-ton force. If you want to understand how that works, “Physics for Idiots” has good explanations, even if you’re not an idiot. Teens looking for the story behind the science can also enjoy “Electric Universe: How Electricity Switched on the Modern World,” an overview of the history and human drama behind electromagnetism’s discovery.
Physics of Motion
Energy and matter together becomes motion. Isaac Newton formulated the Three Laws of Motion on an English sheep farm in the mid-17th century and revolutionized our understanding of the cosmos. He worked out how the motion of the moon affects the oceans on Earth and creates tides. The same laws that govern the fall of an apple from a tree form the basis of our understanding of orbital mechanics – how the planets orbit the sun through the principles of inertia and mass. The online Physics Classroom presents these laws in a clear, accessible way for teens.
Physics of Relativity
Einstein’s Special Theory of Relativity picked up where Newton left off by showing that space itself is warped by gravity, and that even light is affected by it. This effect is so powerful it enables us to see galaxies hidden behind clusters of other galaxies because the galaxies in front create a lensing effect, warping the light around them. Relativity also gave us light’s speed limit – 186,000 miles per second. By this measure, the sun is 8 minutes distant, Saturn is 15 minutes away, and the Voyager 1 space probe at the edge of the solar system is over 17 hours out. Cornell University, the workplace of renowned astronomer Carl Sagan, has a good overview of Einstein’s theory, and yes, there’s a “Manga Guide to Relativity” too.
Grenville Rocks
Just outside Baltimore, there’s a trail in a state park that winds down toward a small river. The river descends down a short rapids, gliding over rock. The rock is unique; it’s over a billion years old. It’s known as the Baltimore gneiss. This is what it looks like:
The DC metro area has been through four mountain-building periods in the past billion years, give or take a few hundred million. The first one raised the Grenville mountains. Over eons, they drifted around the Earth aboard a tectonic plate, eroding, worn down by wind, water and ice. There were four global glaciation events between 900 and 600 million years ago. The ice certainly extended as far as the DC area during these events, and may have girdled the entire planet. In any event, the Grenville mountains were scoured down and the roots that remained became the “basement rock” of the east coast.
Later there was a rifting that split the Grenville rock, with some blocks being dragged out to sea. Magma welled up and spread, then cooled to form a new layer of rock 2,000 feet thick in some areas. These flows formed the Blue Ridge province, and you can see exposures of that rock at Catocin mountain.
Then another plate began converging on the North American continent, with the ocean floor diving beneath the plate. This generated a chain of underwater volcanoes topped by islands running north and south called the Chopawamsic Arc, similar to the arc of islands in southern Alaska. The plate and these volcanoes eventually converged on the eastern North American coast, sweeping up everything on the sea floor in between, carrying it all back onto the continent where it was raised and mashed and mixed with existing rock. This event created the Taconic mountains.
The Taconics wore down. The Acadian mountains formed when continental fragments collided with the east coast. This episode created much larger mountains than the Taconic. To give you a sense of scale, the erosion of the Acadian mountains created pile of sediment to the west. That pile was 9,000 feet high in central Pennsylvania, sloping down to 1,000 ft in Ohio. That was just the stuff left over after the mountains wore down.
The last period of mountain-building was the biggest one. This time, 250 million years ago, Africa and North America collided as all the other continents came together and formed a single supercontinent known as Pangea. This created the Appalachian mountains, and they were as tall as the Rockies and the Alps when fully formed. They’re much smaller now, of course – that’s what 250 million years of constant erosion does to mountains.
Throughout all of this, the billion-year-old Grenville basement rock has been squeezed, heated, folded and torn apart. It’s metamorphic rock, with complex layers. Most of it still lies deep beneath layers of other rock. But there are some areas around Baltimore where you can see it, and Dylan and I did that today.
This rock is older than multicellular life, at least 400 million years older. It was here 500 million years before land plants existed. Our solar system, along with the entire Milky Way galaxy, completes one rotation around the galactic center every 250 million years. This rock has made the trip four times.
Dylan found some rock fragments at the site and brought them home. The rock has been in the water, it’s hydrated and its age shows. It’s very brittle and flakes easily. As we were leaving, one of the rocks he collected split in half. In that moment, he was gazing on the surface of rock that no one, anywhere, had ever seen before – formed a billion years ago, and only now exposed to light and a 16-year-old’s wondering eyes. It’s been a good day.
Martian Geology
This image from India’s MOM mission highlights a region with stress fractures – cracks – in Mars’ crust that can run as much as 3 miles deep. They’re called fossa, sometimes grabens, and they exist on Earth too. Yes, you are riding on a cracked surface. Have a good day.
Elsewhere on Mars, there’s a volcano notable for being about the same height as Mount Everest. (It’s tiny compared to other Martian volcanoes). The linked image shows a forked valley sloping down from the volcano.
https://en.wikipedia.org/wiki/Ceraunius_Tholus
Studies of the valleys suggest they were originally formed by lava flows and later altered by water flow. Think about that. It would require an atmosphere that was warm, wet and large enough to rain down into the caldera at the altitude of Everest’s peak.
Obviously the water cycle and atmospheric dynamics are different on a young planet with about 1/3 of earth’s gravity.
The best estimate of when the volcano’s caldera and channels began filling with water date back to the Late Heavy Bombardment, right about the same time bacterial colonies begin to appear in Earth’s fossil record.
http://onlinelibrary.wiley.com/doi/10.1029/JB095iB09p14325/abstract
A River Runs Through It
What you see here is over 300 million years of geological history at Goosenecks State Park in Utah. You’ve seen similar vistas before, such as looking into the Grand Canyon, and there’s a reason for that.
At the bottom of these chasms is the San Juan river, and at a glance you might imagine the river slowly carving its way down through rock over eons. It didn’t happen that way. What actually happened is much more interesting.
You’ve seen photos of rivers that meander back and forth in a form called oxbow tails, such as this one in the Innoko National Wildlife Refuge in Alaska:
These develop in areas that have low gradients, i.e., the upriver areas are very slightly higher than downriver, just enough for the water to slowly flow downward. The San Juan developed in that way, over 300 million years ago.
But rivers like these don’t cut into rock. They actually tend to collect and carry sediments, then drop them at turns, which is why it ends up winding back and forth.
The continental crust underlying the San Juan river broke off from the supercontinent Pangea and wandered around the globe. It’s still moving west, at about the speed fingernails grow; if you’re living in North America, you’re along for the ride right now.
And so through eons, about 280 million years, the river placidly plodded along, providing dinosaurs and other animals with drinking and bathing water.
Then the mountain building began, in fits and starts, over millions of years. Today that process is called the Laramide and Sevier orogenies. A thin dense layer of underwater basalt rock that makes up the Pacific plate began diving under North America. The angle of the collision was very shallow, but still powerful enough to squeeze and deform the rocks that make up the continental crust.
That compression created the column of mountains that stretch from Canada down through the US and into Mexico. The average thickness of continental crust runs between 22-25 miles. Imagine, if you can, the epic scale at work here; much of the western basin, an area that was once the bottom of a shallow inland sea, being slowly pried upwards. You can duplicate the pattern on a smaller scale by pushing a piece of tablecloth.
The new mountains transformed the gradient of the surface water’s flow. Upriver was now significantly higher than downriver, which in turn generates faster water flow.
Normally when water runs fast, it flows relatively straight, creating long classic valleys. But this river was already formed. The new, faster flow was strong enough to carry sediments out and further downhill, but not strong enough to alter the shape of the river. So it carved down through the rock…in 20 million years.
So what you see here, in a sense, is a region that has been power washed by an incessant high-flow river running 24/7 for 20 million years, steadily working its way down through 300 million years of layers. This all happened in the last 15% of the river’s existence.
So it doesn’t take 300 million years to carve this deep channel. Twenty million years and fast water is enough to make it happen.
Dry Past, Wet Future
I live in the Washington, DC area, was walking past the Supreme Court earlier this week. Like several other DC buildings and museums, it borrows from Greek and Roman architectural traditions and sports a facade that resembles the Parthenon atop the Acropolis in Athens.
The Parthenon was constructed in 447 BC and has been there for 2,462 years, with some changes. It has withstood nearly 25 centuries of weather, being attacked, bombed and burned. As it stands today, it’s both majestic and tragic.
This projection of sea level rise from The 100 Metre Line blog suggests water will be lapping at the stairs of the Court by 2320, three centuries from now. In the nearby fountain at the Library of Congress, the sculpture of the Roman god Neptune will rejoin the sea.
Supreme Court (left) and Library of Congress after 30 meters (98 feet) of sea level rise
After 60 meters (197 feet) of sea level rise
If sea levels continue rising, the entire Court building could be underwater by 2600, 585 years from now.
Washington, DC after 60 meters of sea level rise
Our understanding of climate change is incomplete, so these numbers aren’t perfect. But they are a realistic, educated estimate based on what we know now.
This is not yet foreordained. Perhaps we develop mad geoengineering skills, 3D print massive sea walls, or take other measures to mitigate the climate crisis.
But if we maintain our current course, if we fail to develop a global consensus and act, this becomes a likely scenario. And we must act before the changes become too great to roll back.
Incidentally, the Parthenon is 490 feet, or 149 meters above sea level. Even if all the world’s ice melts, it will remain comfortably above sea level.
The Greeks raised their great buildings to last. We are on track to drown ours.
With thanks to the 100 Metre Line and the DrownYourTown simulator.
Watah
Here’s a bit of good news.
If you check the labels of bottled water sold in the metro DC area, you’ll find a lot of it comes from Pennsylvania. This is a state with 6,391 active fracking wells for natural gas, as you can see here:
http://stateimpact.npr.org/pennsylvania/drilling/
How close are these wells to the sources of bottled drinking water?
Judging by the amount of shelf space it gets in area stores, the Deer Park brand seems to be the most popular. They list the Pennsylvania sources of their water here:
http://www.nestle-watersna.com/asset-library/Documents/DP_ENG.pdf
They list New Tripoli, PA; Bangor, PA, Stroudsburg, PA; Hegins, PA, South Coventry, PA; Pine Grove, PA
A quick survey of these locales in Google Maps shows them to be in the eastern or southeastern parts of the state, pretty well away from the fracking activity. It also makes sense they would be toward the east since their largest markets are all on the east coast.
So it looks like Pennsylvania bottled water, at least the Deer Park brand, is safe from fracking contamination…for now.
Influential Prose 