I’d Like To Go South Please… Now.

’m watching my email for an invitation to fly suddenly to the Southern Hemisphere. Perhaps the Latin American Summer School (being held in Argentina this year) needs an emergency strings lecturer? I’ll be happy to reprise my lectures from the one I taught at in Mexico city in 2000…

Why do I want to go South with such urgency? This is largely because Comet McNaught continues to put on a wonderful show in the Southern Hemisphere. Amara Graps has kindly put several links for us to look at in the comment stream of my Look Up Down South post. Have a look here, here, here, here, and here. I did, and I found this lovely shot (by Mary Fanner – click for larger) of the comet over the beautiful city of Cape Town, which I miss a lot from the days when I helped run the ASTI science education program in 2004:

comet over  cape town by Mary Fanner

There are several more to be found on […] Click to continue reading this post

Unexpectedly On YouTube

third law jet demoI don’t know why this possibility did not occur to me before. So let me give you a heads up if you do demos in your lectures. In Physics 100 (which I taught last semester) and in Astro 100 especially, we do a lot of demos to demonstrate various physics concepts. I did a post on the Newton’s third law jet propulsion demo some time ago (linked photo right). My colleague Ed Rhodes did this same demo in his Astro 100 class.

He received an email from one of the students in the class recently saying “Congratulations, you’ve been YouTubed…”.

Apparently, one of the students in the class used his or her mobile phone camera to […] Click to continue reading this post

Vaporstream or no Vaporstream?

Want to have a confidential email conversation about a sensitive issue? There’s not really been such a thing so far, really. Better to pick up the phone and talk in person. Or meet at random near that noisy fountain in the park. But wouldn’t it be nice to be able to send an email and not worry about it being forwarded on, saved – or “reply-all”-ed to the entire organization? I just heard a piece on NPR about a company that claims to offer this service. It acts as the place where you can send and pickup these mails. Once they are read, they are gone. Self-destructed. All very Mission Impossible

The service is called Vaporstream, and you can hear more about it in the NPR story, by going to the NPR site. I can’t give you a link to the clip directly as it does not seem to be on their site anywhere, so perhaps you will just have to listen to the whole program. (All Things Considered- The Monday 22nd Jan show, toward the last half hour or so.)

Interestingly, it seems that there’s only 8 posts tagged with it on Technorati. It’s been a long time since I saw something with so few entries there! I wonder how long that will last?

I wonder if Vaporstream will catch on and we’ll all be using it regularly in a short time. Will it be one of those things, like YouTube and Google, where we’ll all be wondering what life was like before them?

I find myself confused by why this elementary possibility is not a problem: While […] Click to continue reading this post

What Inspired You?

It’s always interesting to hear from others about what set them on the path they’re on, no matter what career path that is. I just read Chanda’s guest post on the matter over at Backreaction. Chanda is a theoretical physicist in training, and so from my point of view it … Click to continue reading this post

Light Cone

bulb on a stringSo imagine that you’re standing at some spot, holding a big round bulb that can shine in all directions. At a particular time, you switch on the bulb and it shines out brightly. Who has a chance to see the light from your bulb? Let’s not worry about things like buildings, cars, etc., getting in the way of the light, but just imagine it can shine free in all directions. You’ll realize that there is a whole ball of light expanding away from the bulb – light going away from you in all directions. (The edge of that ball describes what is called a sphere, a two-sphere to be precise, denoted [tex]S^2[/tex] in the trade.) The sphere expands at the speed of light. You might imagine that eventually every point in space around you would be reached by your expanding sphere (let’s stay local and not worry about the expanding universe and so forth), and you’d be right. But when? When does it get to some particular point that you might care about? As soon as it takes the light the time it takes to get there, of course. It can’t get there any sooner than that.

Let me put it another way. Your sending out the light is a particular “event”. It took […] Click to continue reading this post

Missed Chance

The show on television called “24” has an interesting format. It is sort of meant to be in real time, and so each episode – roughly an hour long, including advertisements – charts what took place in an hour of a particular day. A whole season is one day. A very harrowing day for the characters in the show, particularly agent Jack Bauer. They are part of an counter-terrorist unit (CTU) trying to save the America from various highly complicated terrorist plots. The terrorists are obsessed with Los Angeles, it seems, which is convenient given that the unit is based in Los Angeles. Having watched two or three seasons of the show now, I’ve also come to appreciate the fact that the terrorist plots hand over to more and more complex and dastardly ones as the show goes along through the day. And the “controlling mind” bad guy earlier in the day is hardly ever the worst and most dastardly person our heroes will meet. There’ll be a really really bad guy along later on with an even worse plan than the one before lunchtime, and so forth. Another reason that it’s lucky that they’re obsessed with Los Angeles, since there’s an excellent supply of theatre and television actors here to be cast in various partsa.

What I’ve really been hoping to see is an episode of the show when Jack Bauer is not saving America/LA. Instead, he’s just… chillin’. Imagine it now: […] Click to continue reading this post

On the EDGE

Golden-rumped Elephant ShrewEDGE here stands for “Evolutionarily Distinct and Globally Endangered” and is a term that was coined to refer specifically to certain threatened species of animal around the world. They’re not always your big marquee animals (Lions and Tigers and Bears! Oh My!), and a great deal of them will be unfamiliar to you. (I’d never encountered the Golden-Rumped Elephant Shrew before, and I’ll admit that my life has been all the poorer for not having known about it before. It’s so cute! Furthermore, it has a golden rump. What’s not to like? Apparently, it is related to an elephant, somewhat distantly. Yes, it has a trunk, but it takes more than that to detemine its relationship to elephants! Update: – Here’s a Wikipedia article on elephant shrews, which could be a starting point for finding out more. The EDGE site has a lot of information too: here.

That unfamiliarity – blissful ignorance on our part – is part of the motivation. There’s a campaign to highlight them more, and raise both funds and awareness to enable […] Click to continue reading this post