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Posts Tagged ‘science

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:

.

..and that’s how you see three planets, one inner, two outer, together on cool fall night.

Written by Influential Prose

May 5, 2016 at 4:22 am

Posted in astronomy, science, space

Tagged with , ,

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.

http://blogs.agu.org/geospace/2016/05/03/scientists-find-likely-cause-recent-southeast-u-s-earthquakes/

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

 

Written by Influential Prose

May 5, 2016 at 3:26 am

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.

Written by Influential Prose

June 26, 2015 at 3:24 am

Cultural Differences in Moral Reasoning

[One of 50 articles written and published for Demand Media in 2013. Published version here.]

Cultural differences in moral reasoning are driven by various influences — history, leadership, religious belief, experiences with peace and warfare, available resources and the strategies for extracting and distributing those resources. These cultural differences are not limited to the scale of nations. There can also be differences in the culture and moral reasoning between schools, communities, companies, even families. Moral reasoning has a way of adapting to or being shaped by people’s needs and perceptions.

Absolutes vs. Relativism
There’s an ongoing, cross-cultural debate on whether moral values are absolute or relative. Are there universal morals that apply to all regardless of culture, or are moral values a negotiation between the environment, natural selection and social conditions? It’s a hotly debated topic, but clearly moral reasoning diverges among cultures. In some areas, gay marriage is accepted and not in others. Some countries permit personal firearm ownership, in others you can be jailed. The same is true for possession of certain plants.

National Differences
Overpopulation has led China to impose some restrictions on family size. Today it has over 1.35 billion people and most Chinese live with an average density of 326 people per square mile. People living at that density calls for, and perhaps requires, a moral system that emphasizes cooperation and harmony — exactly what Confucianism teaches. In China, conditions and moral reasoning lead to limits on family size.

In Russia, conditions and moral reasoning lead to an opposite conclusion. Russia’s population density is slightly below 14 people per square mile, with about 143 million total population. Government policy encourages families to have as many children as they can (which also requires cooperation and harmony).

Japan’s situation is complex. They face a rapidly aging population and steep decline in fertility, in part because strong Confucian values demand marriage before children, but marriage rates are dismally low. Japan is caught between cultural values and an inevitable economic decline unless fertility and immigration increase; thus Japanese moral reasoning is now forced to resolve this conflict to maintain national prosperity.

Economic Differences
Consider a simplified example of conflicting interests between a factory owner and a farmer. To remain in business, the factory owner must balance costs and expenses. This may mean discharging pollutants in the atmosphere because it is the lowest-cost way to eliminate wastes. If costs are not well-controlled, the factory could fail and people would lose jobs. From this perspective, cost control is a moral good.

From a farmer’s perspective, if crops are contaminated by mercury particulates from the factory, the moral good of cost control becomes the evil of food poisoning. Similarly, an agricultural society will have a different moral perspective on some issues than an industrial society. Cultural values — morals — tend to dovetail with practical needs.

On the issue of global warming, there’s a clear clash between the view in academic culture, which is driven by several lines of evidence pointing toward anthropogenic climate change, and the views of fossil fuel and other industries, a culture that tends to combat any conclusion that will affect profits. When scientific facts and self-interest diverge, the effect on moral reasoning is illuminating.

Humanitarian Differences
Cultures vary in how they value others in their midst. Slavery is a stark example, and had its advocates. It is now widely condemned, yet persists in the form of human trafficking, or sex slavery. Sexual slavery victims tend to flow from economically insecure areas to regions of relative stability. When times are hard, the young women who comprise the majority of victims can be manipulated and entrapped with promises of phony jobs. Some locales, most famously Bangkok and Amsterdam, tolerate the sex trade by reasoning that it’s a matter between consenting adults. This blurs the line between consent and coercion and complicates enforcement against human trafficking.

Social Stratification
Other forms of devaluation persist, cutting across lines of ethnicity, gender, age and disability, resulting in societies stratified by economic class (U.S.), social castes (India, Pakistan) and ethnicity (U.S, Japan). Social stratification is inherently hierarchical, a pre-rational behavioral pattern, and proactive moral reasoning is working to reduce it through affirmative action programs in the U.S. and India.

Moral reasoning varies by culture in accordance with what the culture values. As noted American author Robert A. Heinlein pointed out, “Man is not a rational animal. He is a rationalizing animal.” It’s clear that moral values are relative in practice. If there are also absolute universal moral values, no clear consensus has yet emerged that identifies them.

Written by Influential Prose

June 26, 2015 at 3:20 am

Educational Science Games for Teenagers

[One of 50 articles written for Demand Media in 2013]

Educational games can be competitive – teams can vie to build a better tool, such as a water balloon catapult or battling robots. More often, educational games are cooperative activities. You may build something with others, or construct something virtually based on real-world physics using a computer. Learning by doing is the essence of applied science – we experiment, we guess what approaches will solve problems. When we fail, we apply lessons learned and try again. For the games and activities described here, see the Resources listed at bottom to access instructions, videos and links to more fun.

Cooperative Exploration
Some science tasks are too large for small teams to tackle. Crowdsourcing helps break down enormous tasks into smaller chunks, then presents them in a game format that anyone can grasp and play. These games help analyze cancer cells, explore the surface of the moon and ocean floors, find planets around other stars, sort the meaning of whale and bat calls, and classify animals in Africa. There’s much to explore at the Zooniverse.

Electrical Engineering
If you’re interested in building a robot warrior, you needn’t wait to form a team, join a class or enter a competition. There are numerous sources for parts and do-it-yourself guides for beginners. Servos, cameras, motors, controllers, transmitters, batteries, tools – building a robot today is like Legos on steroids. (Lego is also a player – see their Mindstorms NXT kits).

Not all robots are ground-based – some fly. While radio-controlled cars and aircraft have been around for years, it’s possible to build personal autonomous aircraft. You tell them where to go, they fly off and do it. DIY Drones has plenty of guides to get you started. Build for your own pleasure or compete with other local hobbyists to fly faster, higher and longer.

Mechanical Engineering
Building a bridge demands an understanding of materials, their strengths and limitations, the requirements of the site and loads – dead, alive and dynamic. In Bridge Builder, you can test different construction approaches and learn what works. Unlike the real world, when you fail, nobody gets hurt.

Water balloon battles are a summer favorite. You can take it to the next level by building a large slingshot, catapult or trebuchet. Now you can learn the physics of parabolas with real-world target practice. Aim well, or you may soon be all wet! Make magazine has detailed step by step instructions.

Geography
Google Earth is a lot of fun all by itself – you’ve got a whole planet to play with (more, actually – the Moon and Mars is included). At Planet In Action, there’s a collection of games that work together with Google Earth. If you’re looking for multiplayer action, look at Google Earth War, where the entire planet becomes your battlefield.

Want to do a bit of near-space photography? It’s not especially difficult or expensive. Dedicated teams have lofted small weather balloons equipped with cameras 20 miles up to capture astonishing views of earth’s curvature and black skies. Tutorials abound. Create rival teams to see who can fly higher or gather the most interesting photos and videos!

Astronomy
As long as you’re looking up, try running the Messier Marathon. Every spring, conditions are favorable for surveys of 100 deep sky objects. These galaxies, star clusters and nebulae were first discovered and cataloged by Charles Messier, an 18th century French astronomer. Your challenge is to view them all in one evening. You’ll need a good telescope, clear skies and patience. You’ll learn a lot along the way.

Aerospace
Here is a trio of games all built to reflect real-world physics. Two of them emulate real-world vehicles. X-Plane is a sophisticated flight simulator that offers an amazing range of aircraft that you can fly over real-world terrain in real-world weather conditions, with authentic failure scenarios. In Orbiter, you can pilot an Apollo command module to the moon, dock with the International Space Station from a Space Shuttle or Soyuz, then re-enter and land. In the Kerbal Space Program, you build your own spacecraft subject to real-world limitations of materials, weight and fuel. You can build your own moon base, ferry supplies and discover what happens when you run short.

Written by Influential Prose

June 22, 2015 at 10:04 pm

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, a sort of splitting of 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.

Later 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.

Written by Influential Prose

June 22, 2015 at 7:11 pm

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.

Written by Influential Prose

May 10, 2015 at 10:58 am

What’s the Oldest Form of Life?

When I was in high school, we’d study simple forms of life – single cell life,  like a paramecium. And the thing that consistently impressed me was how incredibly complicated these forms of life were. We’d examine a single, basic cell, and find it was amazingly sophisticated. It was enough to make one think that maybe, just maybe, the intelligent design people were on to something.

For much of my life, I’ve been mildly interested in building up a sense of the sequence of life. Wouldn’t it be cool to look at forms of life around us and know, roughly, how long it’s been around?

The puzzle of complexity and the mystery of age drove much of my interest in biology for years. And the key to understanding both is the timeline of development.

We know the earth was frequently subject to heavy-duty bombardment by meteorites during the first half-billion years. This pounding was fierce enough that it’s entirely possible that simple forms of life arose and were wiped out several times.

We also know that the earliest evidence of life we can find dates back the time when the bombardment was winding down. Those early life forms were single cells. And that’s how matters remained…

…for the next 2.5 billion years.

Two and a Half . Billion. Years.

Evolution is driven by changes in the environment. Life that can adapt to change survives. Life that can’t…dies. Sometimes it’s the weird mutant cell that survives, say, a period where it’s colder than normal. That mutant proliferates while others fade away. The mutant moves into colder environments while it’s cousins remain in the tropics. Single cells adapted to a variety of environments, including competition with their own expanding numbers. The development of single-cell life, including the arms race of single-cell biological warfare, went on for time out of mind.

No damn wonder they’re so sophisticated. This chart of cellular biochemical and metabolic pathways resembles a large city map:

biochemicalpathways

All the oldest forms of life began in the ocean. It was only about 500 million years ago – half a billion years – that life moved onto land. There are living fossils among us. Sponges date back 635 million years. Horseshoe crabs, 435 million years. Sharks, over 350 million years. Alligators, more than 200 million years. Ginko trees – there are many of them in Washington, DC – haven’t changed in 170 million years.

But to find the oldest form of life, you need look no farther than the cells of your own body. We are, all of us, walking cell colonies. The cells that form us are, of course, far more advanced than the earliest cells, and they got that way because they had 2.5 billion years to find their groove.

The most ancient forms of life are the building blocks of your life.

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Written by Influential Prose

November 18, 2009 at 8:59 pm

The Biology of Deafness

Employment Matters column, i711.com


According to the biology departments at Gallaudet University and the Medical College of Virgina, at least 85% of deaf people will marry another deaf person.

Many of those marriages will eventually include children, and if their parents became deaf by genetic causes, there’s certainly a chance of the children being deaf too. Among the general population, about 1 in 1,000 children in the US is born profoundly deaf.

About half of all deaf people are genetically deaf, and the other half became deaf through environmental causes. Environmental causes include premature birth, viruses that reach the fetus, and certain drugs that can affect the fetus.

Genes come with on/off switches, so not all genes are working all the time. Some genes are only read during fetal development, others during puberty, and others can be on or off depending on the activity of other genes or the environment.

The genes that cause deafness can be either dominant or recessive. If a gene is dominant, it will be active when only one copy of the gene is present. Recessive genes are only active when two copies are present.

Everyone gets genes from both parents. Dominant genes for deafness can come from either parent, but a recessive gene for deafness means both parents must pass it on for that gene to be active.

Most genetically deaf people inherit recessive genes, which is why deafness can sometimes skip generations – childen may get only one recessive gene from their parents, and so become carriers of the deafness gene, but they won’t be deaf themselves.

Working out how genes interact with each other and the environment is an extremely complex subject, and there are at least several hundred genetic changes that can lead to deafness. But just a few common causes dominate the list. You probably know of some of them, either from personal experience or through people you know.

Genetic causes for deafness are grouped in two ways. One group is linked with other traits, or syndromes. In the second group, deafness appears unrelated to anything else.

The first, syndromic group, include Usher’s, Waardenburg and Pendred syndrome. One feature of Waardenburg is a forelock of white hair, so if you’ve seen that, you’ve seen an example of syndromic deafness. These forms of deafness arise when mutations in a gene or a group of genes affect more than just hearing.

Genes provide instructions – you can think of it as a recipe – for making proteins. Our bodies use some proteins for more than one purpose. If a mutation affects one of these multi-purpose proteins, the effect shows up as a syndrome. Different areas of the body feel the impact of the missing or incomplete protein.

There are also at least 30 genetic causes of deafness that are not apparent through appearance or other issues. Most deaf people – 70 to 80% – are in this group. Of the major causes in this group is a mutation of the GJB2 gene.

This gene makes a protein called connexin 26, which makes a critical part need by cells to communicate with neighboring cells. This communication trouble at the cellular level scales all the way up to the whole individual!

Many genes in both groups have been mapped – their locations are precisely known, and tests for some are available. Some genes are so large that testing them for deafness-related mutations is too expensive, but among the smaller and well-known deafness genes, it’s possible to arrange tests. There are still some genetic causes of deafness where the location of the gene remains a mystery.

Both genes and our environment have a powerful influence on the people we become. But in the end, how we play the environmental and genetic cards we’re dealt has the greatest impact on our lives. The actions we take and the choices we make define us more than anything else.

Related Links:

Hereditary Hearing Loss Homepage

Deafness and Hereditary Hearing Loss Overview

Chart of Inheritance Percentages

Basic deaf-related Genetics

Nonsyndromic Deafness

Finding Genes for Non-Syndromic Deafness

Deafness-related Gene Testing

Written by Influential Prose

September 30, 2009 at 11:54 pm