Clocks, Microwaves, and the Limits of Fermi Problems

I don’t have anything all that new to say about last night’s Cosmos reboot, and I’m leaving for scenic Madison, WI today to attend DAMOP, so I don’t have a great deal of time. Kate did mention something over dinner last night, though, that’s a good topic for a quick blog post. Kate’s a big… Continue reading Clocks, Microwaves, and the Limits of Fermi Problems

Dark Energy, Faster-Than-Light Travel, and Fine Structure Bombs

Figure from my relativity book showing how FTL violates causality.

Last week’s talks were using sci-fi space travel as a hook to talk about relativity, and my original idea for the talk was to explain how faster-than-light travel ultimately ends up violating causality. Some observers will see effects happening before the events that cause them, and that’s just weird. In How to Teach Relativity to… Continue reading Dark Energy, Faster-Than-Light Travel, and Fine Structure Bombs

Long Overdue Snow Physics Post

Snow hanging off the edge of SteelyKid's playset.

Ages and ages ago, I posted the picture that’s the “featured image” above, and asked people to submit physics comments about it. Then I got distracted by a series of shiny things, and never did anything with the handful of responses I got. Because I’m a Terrible Person. Anyway, it’s long overdue, but here are… Continue reading Long Overdue Snow Physics Post

On the Steering of Sleds

Matt Wolbach sliding through a turn on the luge course in Park City, Utah in 2010. Photo from http://commons.wikimedia.org/wiki/File:Matt_Curve-6.JPG

In the previous post about luge, I mentioned that there was one thing that came up when Rhett and I were talking about this, namely why there are differences in times between racers. The toy physics model I set up last time suggests that the difference between riders is only a matter of aerodynamics– two… Continue reading On the Steering of Sleds

Snow Plow Projectile Physics

A snow plow probably filling in the driveway somebody just cleared. From http://snowplowingdenver.com/

We got over a foot of snow yesterday and today, so schools are closed. Except Union is a residential college, so we never close, which means I have to dig my car out all the same. Which I did, clearing a path to the unplowed street, then took Emmy for her morning walk. During which,… Continue reading Snow Plow Projectile Physics