Tailoring eTextbook content to different regions

2 10 2013

Recently, the Los Angeles Unified School District (LAUSD) got some press for its introduction of iPads into their high school classrooms. They have instituted a program to loan iPads to all of their high school students to aid in their studies. Inevitably, the subject of electronic textbooks came up in this discussion.

Electronic textbooks have enormous potential to aid in education. Of course, as is the case with any technology, there are drawbacks.

An electronic text can be updated constantly in the background. As current events unfold, they can be added to textbooks and classroom discussion and thought can be centered around those events. There is no way to do this with paper textbooks without printing a whole new edition and convincing school districts across the entire country to invest in them.

jesusondinoIt is also possible for a school district to get a copy of a textbook from a publisher and tailor it for their schools and students. This could solve much of the turmoil caused be folks like those on the Texas Board of Education. Texas purchases many textbooks and publishers do not want to be burdened with making two versions of a 500-page book. Because of this, there is a possibility that future American biology textbooks will include Creationism, euphemistically called “Intelligent Design.”

This is where we get into dangerous territory. In theory, it would be possible for states with more religious legislators and officials to approve science books with Bible verses in them and the other states to put actual science into their science books. We would risk further bifurcating America by producing two groups of citizens, those who learn about evolution and actual science and those who do not understand science and mistrust it.

My first instinct was to say, “So what? Let those backward states have their pseudoscience. Once they get passed up by the other states, they will see the error of their ways.” Unfortunately, it would not work this way. For things like science, we must have everyone learning the same basic principles and facts. To do otherwise would be risking a dangerous division in our country.

Obviously, this is not a problem that is going to be solved overnight. Maybe it will not be as bad as I think it will be. Hopefully, it will not. That said, this is probably going to come up in one form or another.





Hubble and Doppler Shift

30 01 2013

Edwin Hubble, after whom the Hubble Space Telescope is named, was an astronomer in the early twentieth century. At that time, modern cosmology was still in its infancy and there were many assumptions and false conclusions about the universe.

Probably the most noteworthy assumption of that time was the presence of “island universes.” For years, astronomers had observed strange, rounded clouds in the distant sky. They had assumed that these were other universes, isolated by nothingness. Today, we now know that these are galaxies, collections of billions or even trillions of individual stars, gravitationally bound to each other.

Another assumption was that the universe was static. This is called the “steady-state” model. In this model, all stars and other large objects were fixed in place and the energy and mass densities of the Universe could not change. In this case the energy density is the amount of energy contained within a certain amount of a space, a cubic meter, for example. The same goes for mass density. The Universe’s size was fixed and all matter and energy had to be conserved. Therefore, the density of the Universe remained constant.

Doppler shift

Another basic subject that should be covered here is that of Doppler shift. Doppler shift is a phenomenon that can be observed in every day life. A common example is that of an ambulance driving by with its siren on. As it approaches the listener, the siren’s pitch sounds slightly higher than normal. As it leaves the listener, the siren’s pitch sounds lower. This is because the sound waves are being accelerated by the motion of the ambulance. This causes the crests of the sound waves to become compressed as the approach the listener and expand as the wave source moves away.

In astronomy, the is typically known as “redshift” for receding wave sources and “blueshift” for approaching wave sources. This phenomenon became critical to Hubble’s research in 1929.

Discovery of galaxies

Hubble’s first discovery in 1919 radically altered our understanding of the universe. By identifying several characteristic of certain nebulae, including Andromeda (M31), he realized that these were not the island universes that everyone had assumed them to be. They were, in fact, other galaxies like our own and were much more distant than previously thought. Naturally, there were those in the scientific community who resisted the notion at first, but they were eventually compelled by the evidence.

Redshift of the galaxies

This discovery paved the way for another, equally important, realization that came ten years later. Hubble observed that nearly all the other galaxies were receding from our own. Working from the assumption that the galaxies most similar to ours should have similar types of stars in similar proportions, Hubble observed that most of these galaxies were redshifted, indicating that they were moving away from us with extreme velocity.

Expansion of the Universe

Furthermore, the farther the galaxies were, the greater the redshift. This means that the farther a galaxy is from us, the greater its speed away from us is. This can be represented by the following equation, called Hubble’s Law.

v = H0D

v is the speed with which a galaxy is moving away from us.
D is our distance from that galaxy.
H00 is the Hubble constant, which describes the relationship between the two variables.

The Hubble constant has been changed and updated as new cosmological observations and measurements have been made over the past 90 years. As of research performed with the Chandra X-Ray Observatory in 2006, one current estimate places the current Hubble constant at 77 kilometers per second per megaparsec (77 [km•s-1]•Mpsc-1). That is, that, in one dimension, 77 kilometers of space is being added to each linear megaparsec of space every second. This gives us a rate of expansion of the universe.

Space is expanding at every point in the universe but the expansion is only observable at distances where it can overcome the four basic forces, including gravity.

Hubble sphere

Since Hubble’s law states that recessional velocity will increase with relative distance, this would mean that, eventually, the recessional velocity would equal the speed of light. We could then rearrange the law to find what distance is required for this to happen.

If v = c = H0D,
then D = c/H0.

In this case D could be represented by RHS, the radius of the Hubble sphere, or Hubble volume. The Hubble sphere is a spherical region around an observer that defines the boundary of the observable universe. At this point, the light from distant galaxies becomes so redshifted that we can no longer observe it because they are receding at a rate of speed faster than the light they emit.

We have no way of observing anything beyond the Hubble sphere because the distances are so vast that light is not fast enough to overcome the expansion of the Universe to reach us. There is likely more universe beyond this sphere, but we simply cannot see it.

When we run the numbers, we find RHS to be approximately 13.9 billion lightyears. Since the universe is roughly 13.7 billion years old, any light we see at the edge of the Hubble sphere has been traveling toward us almost as long as the Universe has allowed light to travel.

The difference between the age of the Universe and the size of the Hubble radius can be explained by taking into account the acceleration of the Universe’s expansion. The Hubble constant is actually variable and is increasing slowly.


All of this forms the backbone of modern cosmology. Without Hubble or the work he and his collaborators did, it is likely that cosmology would not be where it is today.





Teach doubt in school

18 02 2011

I enjoyed my time in high school. I still value that experience a great deal. It helped me start to figure out who I am and where I want to go. In particular, the science programs had a big impact on me. From the Saturday Science program there that I participated in as a 3rd, 4th, and 5th-grader, to the four years of science that I took there, to the scholarship I won from the North Central Science Department at graduation, it was a great place to learn. Looking back, however, there was something missing, a lesson in reason and skepticism.

I did not really get into skepticism – real skepticism – until my junior year in college. Basically all that happens in high school science classes is learning the specific subject in question, be it physics, chemistry, biology, zoology, or some other subject. The scientific method is only briefly glossed over in the first class each year.

I think that in order for science classes to really teach science, they must teach the philosophy behind it, as well as the actual means. This can take a couple of forms. It could be a dedicated course, within the schools’ science curriculum. This course would  give students a firm grounding in rationality, skepticism, and inquiry. It would teach them how to question and test claims. The alternative to this solution would be to include a more in-depth lesson in the scientific method and scientific inquiry that might last a week (5 class sessions) or so.

I would make the argument that while we improve our education system across the country, we should look at where our science curricula might be lacking. We certainly could do with more rational analysis and thought in this country.





The Messier catalog is weird

5 02 2011

Charles Messier was a French astronomer who lived from 1730 to 1817. He was a comet hunter. In the process of cataloging comets, he frequently stumbled across objects that, to him, initially appeared to be comets. He compiled a list of 110 of these objects, which is now called the Messier catalog.

Andromeda_Galaxy_(with_h-alpha)

M31 - Andromeda Galaxy

These Messier objects are now well known to nearly all astronomers. Most of these are spiral galaxies or globular clusters. M57, also known as the Ring Nebula, is a planetary nebula.

When I first learned about the Messier catalog and the reasons behind its creation, I was a little confused. Why would someone make a list of things they are not looking for? I suppose it makes sense that if you are committed to a somewhat repetitive mental task, you would want to make it easier for yourself to avoid common mistakes. That is the likely initial purpose of the catalog.

I suppose that through an 18th century telescope, it might be a little difficult to distinguish between a comet, a galaxy, a globular cluster, and a planetary nebula. While telescopes did enable astronomers to see deeper into space than they had in the centuries before, 18th century telescopes are put to shame by their 20th and 21st century counterparts.

Messier cataloged galaxies centuries before we knew what galaxies really were. It was not until the 1930’s that Edwin Hubble proved conclusively that they were, in fact, extragalactic objects and were millions of lightyears distant. In Messier’s time, people simply assumed that they were just nebulae.

Whatever the Messier catalog’s initial reasons for existing, it gives amateur and professional astronomers a great jumping off point for observing relatively nearby objects.





Astronomy Course Schedule, Mark I

31 01 2011

If you have been reading my blog, you know that I have been toying around with the idea of going back to school for my Astronomy Bachelor’s degree. I may even continue on to a Master’s degree. I am not certain if I have it in me to the full PhD/postdoc route. But grad school is a decision to be made a year before graduation.

I talked with an Astronomy/Astrophysics academic advisor at Indiana University back in December. Here is the rough course schedule we came up with.

  • Summer 2011
    • MATH-M211 Calculus I (4 credit hours)
  • Fall 2011
    • MATH-M212 Calculus II (4 credit hours)
    • PHYS-P221 Physics I (5 credit hours)
    • AST-A221 General Astronomy I (4 credit hours)
  • Spring 2012
    • MATH-M311 Calculus III (4 credit hours)
    • PHYS-P222 Physics II (5 credit hours)
    • AST-A221 General Astronomy II (4 credit hours)
  • Summer 2012
    • MATH-M343 Intro to Differential Equations with Applications I (3 credit hours)
    • MATH-M303 Linear Algebra for Undergraduates (3 credit hours)
  • Fall 2012
    • MATH-M312 Calculus IV (4 credit hours)
    • PHYS-P331 Theory of Electricity and Magnetism I (3 credit hours)
    • PHYS-P441 General Astronomy II (4 credit hours)
  • Spring 2013
    • PHYS-P332 Theory of Electricity and Magnetism II (3 credit hours)
    • PHYS-P453 Intro to Quantum Mechanics (3 credit hours)
    • AST-A451 Stellar Astrophysics (3 credit hours)
  • Fall 2013
    • AST-A305 Modern Observational Techniques (4 credit hours)
  • Spring 2014
    • AST-A452 Extragalactic Astrophysics (3 credit hours)

Nearly all of my liberal arts and non-degree credits are done and were taken recently enough that I can count them toward this degree. I will also need to take an intensive writing course at some point in this degree program. Given all that math and physics, it would be a welcome break.

I am making a pretty big assumption with this course schedule. That assumption is that I quit my steady, well-paid, job with health benefits and go back to school full time for another three years. That is a decision I am still wrestling with and I am far from making a decision. This is really just a thought exercise for me to see how long it would take me to complete this degree that I have been eying since  2007.





More than a body of knowledge

28 12 2010

“Science is more than a body of knowledge; it is a way of thinking. I have a foreboding of an America in my children’s or grand children’s time … when awesome technologi­cal powers are in the hands of a very few, and no one representi­ng the public interest can even grasp the issues; when the people have lost the ability to set their own agendas or knowledgea­bly question those in authority; when clutching our crystals and nervously consulting our horoscopes­, our critical faculties in decline, unable to distinguis­h between what feels good and what’s true, we slide, almost without noticing, back into superstiti­ons and darkness.”

-Carl Sagan





Clinging to relevance

14 12 2010

I have been thinking about the relationship between religion and science lately. It has always been a strained, complicated relationship. To be honest, I really have never understood the conflict. They seem to deal with two very separate areas of human thought. Then it struck me, this was not always the case. During the Dark Ages, the church dictated what science could and could not say. Today, we have a battle for relevance between science and religion and religion is losing.

There is a long history of religious institutions acting as a road block to scientific or social progress. The Catholic Church censured Galileo for his scientific conclusions. Baghdad was the center of scientific discovery on Earth for centuries until conservative Islamic forces took hold. Then there is the Catholic Church’s stance on contraception, claiming that it is sinful because it prevents new life. (This seemed like an odd argument, seeing as that is the explicit purpose of contraceptives.) In 2009, the Pope went as far to say that condoms help spread the AIDS virus. He said this on a trip through Sub-Saharan Africa, where about 22 million people are infected with HIV. There are a host of other examples.

Really, what we can see here is a religious establishment, centuries old, that is finding its ship in shallower and shallower waters. With the increasingly educated global population and the persistent advance of scientific knowledge, it is harder for them to maintain previous public opinions. There is little religious leaders can do about this trend except try to modernize their respective faiths much as possible.

In a world where fewer and fewer of our problems can be solved with faith and spirituality, religion can no longer offer us the advice or insight we need. If anything, it is doing the exact opposite at a time when we cannot afford many mistakes. Humanity needs clear thinking and a sharp turn toward rationality if it is to survive.