Category: Time

Back-of-the-Envelope Gravitational Which-Way

There’s a new Science Express paper on interfering clocks today, which is written up in Physics World, with comments from yours truly. The quote is from a much longer message I sent– with no expectation that it would end up as anything other than a pull quote, I might add, but I thought the background… Continue reading Back-of-the-Envelope Gravitational Which-Way

Super Bowl Athletes Are Scientists At Work

I wrote up another piece about football for the Conversation, this time drawing on material from Eureka, explaining how great football players are using scientific thinking: Seattle Seahawks cornerback Richard Sherman gets called a lot of things. He calls himself the greatest cornerback in the NFL (and Seattle fans tend to agree). Sportswriters and some… Continue reading Super Bowl Athletes Are Scientists At Work

What Does a Faster-Than-Light Object Look Like?

A dog and cat interacting with an FTL alien, as seen by the dog, with extra events added.

I exchanged a bunch of emails a week or two ago with a journalist who was working on a story involving the possibility of faster-than-light travel. He wanted me to check some statements about the relationship between FTL and causality. FTL creates problems for causality, because if you have an object moving faster than light,… Continue reading What Does a Faster-Than-Light Object Look Like?

Time Is What You Measure With a Clock

Figure from How to teach Relativity to Your Dog, showing the inability of moving observers to synchronize their clocks.

Last year, Alan Alda posed a challenge to science communicators, to explain a flame in terms that an 11-year old could understand. this drew a lot of responses, and some very good winners. This year’s contest, though still called the “Flame Challenge,” asked for an answer to the question “What Is Time?” This is a… Continue reading Time Is What You Measure With a Clock

How to Teach Relativity to Your Four-Year Old

Don't shoot the piano player

SCENE: The library at Chateau Steelypips. DADDY is typing on the computer, while THE PIP plays on the floor. Enter STEELYKID. STEELYKID: I’m already four years old. DADDY: Yes, yes you are. THE PIP: Thbbbbbbbpppt! STEELYKID: How old is The Pip? DADDY: Eleven months. Not quite one year. STEELYKID: When The Pip is four, how… Continue reading How to Teach Relativity to Your Four-Year Old

Final Notes on a Toy Model of the Arrow of Time

We’re in the home stretch of this term, and it has become clear that I won’t actually be using the toy model of the arrow of time I’ve talked about in the past in my timekeeping class this term. These things happen. Having spent a not-insignificant amount of time playing with the thing, though, I… Continue reading Final Notes on a Toy Model of the Arrow of Time

Course Report: A Brief History of Timekeeping 03

It’s been a little while since I wrote up what I’ve been doing in my “Brief History of Timekeeping” class, because I was out of town, and then catching up from being out of town. Some of this material has already appeared here, though, so I can hopefully catch up a lot of stuff in… Continue reading Course Report: A Brief History of Timekeeping 03