Astronomy

Category archives for Astronomy

Throwback Thursday

OK, the photo above is a recent picture of me– yesterday, in fact. But the spiral-carved rock I’m standing next to was carved that way a bit more than five thousand years ago, so that ought to count as a throwback… We’ve been in Dublin the last few days, and on Thursday we took a…

Right around the time I shut things down for the long holiday weekend, the Washington Post ran this Joel Achenbach piece on mistakes in science. Achenbach’s article was prompted in part by the ongoing discussion of the significance (or lack thereof) of the BICEP2 results, which included probably the most re-shared pieces of last week…

I didn’t plan to do a follow-up to yesterday’s post about the optics of sending messages with lasers, but then I starting idly thinking about detection, prompted in part by a bunch of conversations with my summer students about single-photon detectors. which led to scribbling on the back of an envelope, which led to Googling,…

Interstellar Laser Communications

In the comments to yesterday’s grumpy post about the Fermi paradox, makeinu raises the idea that advanced aliens would be using more targeted communications than we do: On the point about electromagnetic communications: even we are now using lasers to target communications with space, because it’s simply more efficient and reliable. It’s also basically impossible…

Fermi Fallacies

I’ve seen a bunch of people linking approvingly to this piece about the “Fermi paradox,” (the question of why we haven’t seen any evidence of other advanced civilizations) and I can’t quite understand why. The author expends a good deal of snark taking astronomers and physicists to task for constructing elaborate solutions to Fermi paradox…

A Rock the Size of Jupiter?

For some reason, the topic of really big rocks came up at dinner the other night, and SteelyKid declared that she wanted to find “A rock as big as the solar system.” We pointed out that that was pretty much impossible, more or less by definition, rocks being sub-parts of the solar system. “OK, how…

Cosmos Reboot Wrap-Up

The Cosmos reboot season finale (or possibly series finale; not sure if they’re trying for a second set of episodes) was last night, but I wasn’t able to take part in the live-tweeting of it thanks to a super-restless Pip who didn’t drop off until 9:30 EDT. I suppose I could’ve waited to start the…

Cosmos and Priorities

While solo-parenting Sunday night, I still managed to get free of The Pip just barely in time to catch the start of Cosmos. This was a strange episode in a couple of ways, chiefly having to do with the selection of topics. For one thing, there’s no small irony in the fact that following a…

This coming fall term, I’ll be teaching Astronomy 052, “Relativity, Black Holes, and Quasars,” because the guy who has traditionally taught it (a radio astronomer who studies active galactic nuclei) has to do other courses instead. But I said “Well, hell, I’ve written a popular audience book explaining relativity. I can teach that.” And since…

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…