It’s been a few years since I’ve actively moderated the comments here, so now I have about 13,000 pending comments to moderate. The vast majority, maybe all of them, are spam. I’ve installed a new plugin to stem that tide, so it should be more manageable going forward.

What this does mean is that if you’ve posted a comment here in the past few years and it hasn’t been approved, I might end up deleting it when I bulk delete all those pending comments.

So if you’ve commented here, and it is not displaying yet, please send me an email (me (at) this website’s domain) or comment here to let me know. In a couple weeks, I will delete all these pending comments to have a clean slate going forward.

# Logarithmic history or geography class

What if there was a class that attempted to cover all of space or all of time?

I was curious about this, so I chose the shortest scale of each, divided up the power of tens, then spread them out over the course of 10 to 12 weeks.

For example, for time, I chose 1 year as the smallest range to look at – the first week’s topic would cover the past 10 years. Then, since the universe is about 12 billion years old, or $1.2 \times 10^{10}$ years, each week would look back another factor of 10 years. The 2nd week would cover the period from 100 years ago to 10 years ago, and so on.

In practice, this would be the topic coverage for a 1-semester history lesson (I’m obviously glossing over some important topics):

## “History” Class

 Week Years ago Topic 1 10 a Last 10 years 2 100 a World Wars, information age 3 1000 a modern religion, science, industry 4 10,000 a development of human agriculture 5 100,000 a development of clothing, fishing, domestic animals, art 6 1 Ma Homo erectus, neanderthals, Homo sapiens, controlled fire 7 10 Ma beginning of horses, insect diversification, chimpanzee and human ancestors divide, mammoths, ice age 8 100 Ma whales return to sea, bees, T. rex, South America leaves Antarctica, Atlantic Ocean forms 9 1 Ga possible Snowball Earth, first protozoa, worms, fungi, arthropods, continents shift, land-dwelling life starts, Pangea, dinosaurs 10 10 Ga Big Bang, galaxies form, solar system and Earth form.

## “Geography” class

On the other side of things, a space-centered class could break down like this:

 Week Distance away Topic 1 100 m South Loop, Chicago 2 10 km Chicago 3 1000 km Midwest USA 4 100,000 km Earth 5 1 au The sun and inner planets 6 10 au All planets in the solar system 7 1000 au Kuiper belt on edge of our solar system 8 1 ly Oort Cloud on edge of our solar system, nearest star Proxima Centauri 9 100 ly local stellar neighborhood 10 10,000 ly Milky Way Galaxy 11 1 Mly Local Group (of galaxies) 12 100 Mly Observable universe

Kinda puts things in perspective for me. I forget, sometimes, how big our solar system is, and how recent humans came into being.

Additionally, it strikes me how interdisciplinary either of these courses would need to be. Crossing scales of time and space requires different lenses and tools.

# Midwest Theory Get-Together 2013

I was excited to attend the Midwest Theory Get-Together at Argonne National Lab again this year. There were many interesting talks, and I was glad to get an update from the many diverse fields of nuclear theory.

I was especially excited about the last talk of the second day. Mridula Damodaran from Purdue gave a talk about parallelizing the BUU transport model. I wish her success, as I’ve been using a BUU simulation for awhile and the longer simulation runs take 1-2 days — a bit longer than is convenient.

During the Get-Together, I recorded the titles of all the talks that were given, in case I wanted to reference them later, and in case others did too. This record is attached to this post.

# What should we be teaching in the STEM classroom?

My friend Seth Hawkins, who teaches in a high school, recently posted a link to an SMBC comic about the typical, frustrating method a student takes to completing a homework problem in math. This humorous link led to a more serious discussion about what we should be teaching our students.

# Cooperative Income & Expense Sharing

I hope to live cooperatively with others in my life. One way is sharing income and expenses. Within are several models that I just thought of, with some sample people, income, and expenses.

# Value of a liberal education

A running current through my mind has been the value of a liberal education. My officemates from China and Vietnam have talked about how they didn’t have hobbies growing up, since their parents strongly encouraged them to study hard, to the exclusion of everything else. This can be very efficient in creating people who are very good at a very narrow skillset. However, when it comes to working as a team or public speaking, they are at a disadvantage to many students from the US. Even worse, if it turns out that they don’t enjoy doing the job that they were trained from a young age to do, then it can be very difficult for them to find their own path.

# Perspective and proper citation

This might sound cheesy, but I find it incredible that we live on a planet that is so very small on the cosmic scale, but so big on a human scale. How insignificant we are, yet how important our actions are on a human scale.

Earth, as seen from the International Space Station
(Image Credit: ISS Expedition 7 Crew, EOL, NASA)

Also, I found this image while searching for a space picture for my business card (custom-made here). I was looking specifically for images of the Earth seen from space. I honed in on this one and wanted to find out where the original was. As it turned out, many many people had reposted it without citing the source. I eventually used tineye to hunt down all instances of this image on the internet, to bring you the source that the photo is linked to above.

I’m still not sure whether I have permission to use this on a business card. I read their image use guidelines, but I couldn’t figure out whether this would count as “advertising” or not, so I emailed the contact on their advertising guidelines page. I’ll update this page when I hear back from them.

# Student epiphany in the physics lab

In Carl Sagan’s book Pale Blue Dot: A Vision of the Human Future in Space (1994), page 159, the renowned astronomer and science popularizer wrote:

It is sometimes said that scientists are unromantic, that their passion to figure out robs the world of beauty and mystery. But is it not stirring to understand how the world actually works—that white light is made of colors, that color is the way we perceive the wavelengths of light, that transparent air reflects light, that in so doing it discriminates among the waves, and that the sky is blue for the same reason that the sunset is red? It does no harm to the romance of the sunset to know a little bit about it.

(as quoted in Today in Science History)

I had that kind of experience in the introductory laboratory I was teaching yesterday. We were using a digital spectrometer to investigate the wavelengths of light that were emitted from various objects like gas discharge tubes and the ceiling lights. The students learned that there was very little red in the ceiling lights, so that’s why red things in the room always look faded, and especially that the red light from the computer monitors looked more vibrant than the light from the paper. One surprised student said to me, “So we can’t even trust our eyes in this experiment?!”

This is the epiphany that I live for in the classroom – that the world we perceive is not always the world as it is, and we can use tools and science to help remove some of our biases.

This, to me, is beautiful.

I was reading about Fortran’s intrinsic function REAL recently and discovered that it behaved inconsistently, so I fixed it by overloading the function in a module that I generally use everywhere.