Terraforming Mars

Image Credit: NASA/JPL-Caltech

Jason Shankel has an article on how we could go about changing the surface of Mars into something humans can live on. He does an excellent job of condensing the not insignificant literature on terraforming the red planet.

Starting with an explanation of Mars’ geologic history, Shankel addresses Martyn Foggs’ list of critical challenges:

  1. The surface temperature must be raised
  2. The atmospheric pressure must be increased
  3. The chemical composition of the atmosphere must be changed
  4. The surface must be made wet
  5. The surface flux of UV radiation must be reduced

— Shankel (2011): How We Will Terraform Mars on io9.com.

The Martian Surface as seen by the rover Opportunity. Image Credit: NASA/JPL-Caltech/Cornell/ASU

The article is expansive in its detail, provides a wonderful primer on the red planet, and demonstrates an excellent application of planetary system science (as opposed to Earth system science) to what would be an enormous geoengineering project. For example, to warm up the planet, Shankel starts with several approaches:

so how do we warm up the Martian poles? Several approaches have been suggested, from spreading dark material on the poles to lower their albedo, to industrial ice farming to good old fashioned thermonuclear detonations.

— Shankel (2011): How We Will Terraform Mars on io9.com.

He then goes into detail. Lots of detail, in a quite readable form.

A desert in Algeria. Image by islapics via Wikimedia Commons.

Human Evolution: A Family Tree

The Smithsonian has an excellent, interactive, family tree for humanity that goes back 6 million years.

io9 has a neat image of key primate and homonid skulls that show the story of human evolution, and how we know about it.

Image via io9. (The skulls come from the collection of the University of Leiden and were labeled by Roosje de Vries.

Boys vs. Girls in Math: The Difference is Only Cultural

Boys tend to be better at math. That’s been the stereotype, but a new study (Kane and Mertz, 2011) published in the Notices of the American Mathematical Society provides evidence that, at all levels, it’s only because society and culture tend to support, and advance the stereotype.

… we conclude that gender equity and other sociocultural factors, not national income, school type, or religion per se, are the primary determinants of mathematics performance at all levels for both boys and girls. … It is fully consistent with socioeconomic status of the home environment being a primary determinant for success of children in school.

— Kane and Mertz, 2011: Debunking Myths about Gender and Mathematics Performance in Notices of the American Mathematical Society.

Kane and Mertz compared math achievement in a number of countries. If there were some genetic reason for different math abilities then boys should be better than girls everywhere. This is not the case. In more wealthy countries where there is more equality between the genders, the mathematics performance gap disappears.

In poorer countries like Tunisia boys tend to do better at math, while in rich ones like Barhrain girls do better. However, in places with greater equity between the genders, like the Czeck Republic, boys and girls do equally well. Figure from Kane and Mertz (2011).

Sensory Integration

… people learn a visual task better when it’s accompanied by sound, for instance — even when they are later tested using only vision.
— Humphries, 2011: The new science of our cross-wired senses in The Boston Globe.

What I think this means, is that there is now scientific evidence to support the widespread use of sound effects in lectures/presentations. Woohoo!

For the educator, the interaction between sound and vision is one of the fascinating findings of recent research on how our senses interact (see also the work of the Visual & Multisensory Perception Lab). It seems to add some support to the arguments for multimodal learning; rather than just targeting specific learning styles — auditory vs visual vs kinetic etc.– to specific people, including multiple styles of information should help everyone learn better.

But beyond just education a better understanding of how the senses interact has a lot of implications.

… what people saw affected what they heard; that certain types of music or background noise affected how food tasted; and that smells could influence how a texture felt to the touch.

— Humphries, 2011: The new science of our cross-wired senses in The Boston Globe.

This research is already affecting how things are marketed and presented to us.

A study published this year showed that people thought a strawberry mousse tasted sweeter, more intense, and better when they ate it off a white plate rather than a black plate.

— Humphries, 2011: The new science of our cross-wired senses in The Boston Globe.

This research is also pertinent to the issue of Sensory Integration Disorder, which, by some estimates, affects somewhere between 1 in 6 and 1 in 20 children.

Visit to the Quarry/Landfill

We discussed quite a variety of topics just based on the visit to the landfill/quarry.

A single, half-day, visit to the landfill and quarry brought up quite the variety of topics, ranging from the quarry itself, to the reason for the red colors of the cliff walls, to the uses of the gases that come out of the landfill. I still have not gotten to the details about the landfill itself, but I’ve put together a page that links all my posts about the quarry and landfill so far.

There was so much information that we spent the better part of the following week debriefing it in the middle-school science class.

Click the image for more details.

The map below gives a good aerial view of the site.


View Landfill and Quarry (as of 11/26/2011) in a larger map

The Water Cycle … at the Quarry

The water cycle, at the quarry.

The water cycle is intricately tied to all the other topics that came up on our visit to the quarry/landfill. For some things, the tie to water is direct and inextricable.

  • It’s groundwater that dissolves the pyrite in the coal seam and then precipitates an orange iron stain on the quarry cliffs.
  • Rainwater seeping into the landfill leaches out chemicals that have to be prevented from getting into the groundwater, rivers or lakes.
  • Gases like hydrogen sulfide can react with water (and oxygen) in the air to produce acid rain. Not to mention that water is needed for the decaying processes that produce the hydrogen sulfide, and other landfill gases like methane, to begin with.

For other things the link to water is not necessarily so obvious:

  • The sediment that was compressed into the limestone that is being quarried, was formed beneath the shallow seas that once covered this region in the geologic past. Limestone is also dissolved by rainwater to create caverns, underground rivers and spaces for geodes.
  • Methane gas not only requires water for it to be released via decomposition of garbage, but also produces carbon dioxide when burned. Carbon dioxide is a greenhouse gas, so it affects the global temperature and contributes to the melting glaciers, rising sea levels and changes in climatic patterns such as the amount of rain we’re going to receive in the midwest.

The water cycle picture starts simply, but gets complicated very quickly.

A bigger, fuller picture of the water cycle as it interacts with the quarry.

A Guide to Better Blogging

Dan Frommer has posted a guide called, “10 steps to better blogging“. His rules are aimed at commercial bloggers/journalists, but even for the hobbyist/student there are some noteworthy points (certainly ones I try to follow):

  • 1. Accuracy is essential: Be forthright about errors and fix them.
  • 4. Cite your sources: It’s honest, and honorable to give credit where it’s due.
  • 7. Grammar and spelling are important: You don’t necessarily have to use the Queen’s English but use language intentionally.
  • 10. Try new things: It’s a new medium so there are lots of areas for discovery.

Most of these are just the basic elements of good writing.

I’d also suggest that it’s important to include your perspective wherever you can. There are a number of great places that aggregate a lot of good information, but for the aspiring writer, adding your unique point of view should help find your voice.

(found via The Dish).

Limestone Quarry

The quarry's primary purpose is to extract limestone for construction.

The landfill/quarry we visited was originally a limestone quarry; once they had the hole in the ground they needed to fill it with something so why not trash (and why not get paid to fill it).

Shoveling boulders. The rock pieces look small but only because the shovel is so big.

The limestone bedrock is blasted daily to create some massive boulders. The boulders are then loaded on some equally massive dumptrucks. There are scarce few minutes between trucks, so a lot of rocks are being moved.

Dumptruck moving rocks. Massive boulders in the foreground.
Unloading dumptruck.

The trucks then dump their load into a large building where the rocks are crushed. Our guide made us stop the bus to watch the process. While watching a dumptruck unloading might seem mundane, the enormous size of the truck and its boulder load did seem to captivate the students.

Once the rocks are crushed, the resulting sediment is sorted by size (sand, pebbles and gravel, I think) and piled up. The piles are massive. I’ve been wanting a good picture that shows the angle of repose; I got several.

The angle of repose of a pile of sediment. Also notice the greenish color of the water in the pond to the bottom left. Water with lots of fine limestone particles (silt) and dissolved limestone, tends to have that color.

The pebbles and gravel are used for road construction and provide a matrix for concrete.

Since limestone dissolves fairly easily in rainwater, the sand-sized and smaller particles (< 2mm diameter) aren't used for construction -- hard, insoluble quartz sand is preferred.

Limestone: calcium carbonate (CaCO3)

However, the limestone sediment piles sit out in the open and some the finer grains (silt sized particularly), and any dissolve calcium carbonate, get washed into the nearby ponds, which turn a beautiful, bright, milky green.

Finally, in addition to the limestone sediment piles, there is also one enormous pile of broken up concrete. One of the things that stuck with the students was that fact that you can recycle concrete.