Built on Facts

Archives for September, 2009

Space Solar?

In theory I like solar power a lot. There’s a lot to be said for energy that falls from the sky for free for as long as we care to use it. But actually getting that energy to do useful work in an economical way. Solar panels are expensive and not terribly environmentally friendly to…

Sunday Function

Sometimes in math we’ll understand one aspect of a problem very well, while at the same time we understand another aspect of a problem very poorly. For instance, take the prime numbers. According to the prime number theorem, the number of prime numbers below x is approximately given by: Where pi(x) is the prime counting…

The Moon is a Not-So-Harsh Mistress

Astronomers and space exploration enthusiasts around the web are expressing lots of enthusiasm for the discovery of water on the moon by the Indian Chandrayaan-1 orbiter. Long story short (Ethan has a good version of the long story), the probe discovered relatively large quantities of water frozen throughout the lunar soil just below the surface.…

Out, Damn’d Spot!

Ideas about the nature of light have been around for thousands of years, but until Newton came along in the 17th century most of these attempts were little more than speculation. Newton himself held to the view of light as composed of huge numbers of tiny “corpuscles”, or particles, which bounce of mirrors and are…

Easy + Easy + Easy = Impossible

Every once in a while it’s a good idea to remember that even the simplest-looking physical systems can have completely bonkers behavior. The pendulum is certainly one of those systems. It’s so simple that it’s a mainstay of freshman classes, for technical and non-technical majors alike, though even then we do have make an approximation…

A quick contour integral.

Note to the reader: this post is relatively stiff mathematically. For those not mathematically inclined, I think you might enjoy reading it anyway and enjoying it as you would a tour of a widget factory; even if you’re not worried about the details of the nuts and bolts, it’s fun to see it done. While…

Sunday Function

The vast majority of the functions we’ve talked about over all these Sundays have been ones that are expressible as a relationship between two numbers x and y. Sometimes the relationship is simple, sometimes it’s fairly complicated. Mostly though, we just work according to the function as though it were a little machine. Take a…

WiFi and Radiation

I note an interesting short piece by James Hrynyshyn about a bit of a local controversy in Nova Scotia about the installation of a tower to provide wireless internet to the area. Leading the opposition is a guy worried about the health effects: “I think over a period of time it will change the DNA…

CARS and other horrible puns

Let’s say you’ve got a water molecule. It doesn’t have to be water, but it helps if it’s one we can easily picture: You can imagine water vapor as an ensemble of many of these molecules flying and bouncing around in their container. This translational motion is not the only kind of motion they’re executing.…

Graduate School vs. Work

One of my fellow ScienceBloggers, ScienceWoman, has made a few waves by saying the following: I am against accommodating our full-time worker, part-time graduate student students by moving a significant number of our classes to evening hours. There I said it. I don’t want to make life easier for someone who is working very hard…