April 2010

False-colour astrophotography explained

The Hubble Space Telescope captured this image of the Carina Nebula on February 1 and 2, 2010. The colours follow the so-called Hubble palette, which I describe later in this entry: red represents sulfur, green hydrogen and nitrogen, and blue oxygen. Image credit: NASA, ESA, and M. Livio and the Hubble 20th Anniversary Team (STScI).

Since this weekend marks the 20th anniversary of the launch of the Hubble telescope, I thought it would be worthwhile to explain the false-colour images taken by the Hubble’s cameras — why they’re in false colour, what the colours represent, and how it’s done. False-colour astrophotography is not unique to Hubble; it’s used at observatories on the ground around the world, and by professional and amateur astronomers alike. I could do it myself, down the road. So here’s my best stab at explaining it.

Electromagnetic spectrum But before we can explore what false colour is, and why astronomers use it, we need to explain what true colour is — and that requires us to talk a little bit about light.

Visible light represents only a small piece of the total electromagnetic spectrum, which ranges from from high-frequency, high-energy and short-wavelength gamma rays to low-frequency, long-wavelength and low-energy radio waves. Tucked between the ultraviolet and the infrared, visible light is, by definition, what part of the spectrum detectable by the human eye: wavelengths between about 380 nanometres (violet) and 760 nm (red) — or, to put it another way, frequencies between 400 terahertz (red) and 790 THz (violet). In a nutshell, each colour we perceive is simply light at a specific wavelength.

(For reasons that will become clear later on, I’m going to talk about wavelengths in nanometres, rather than frequencies in terahertz.)

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First light from the Solar Dynamics Observatory

Check out this full-disk view of the Sun on March 30, taken by the newly launched Solar Dynamics Observatory and released this past week:

SDO image of the Sun in ultraviolet. Credit: NASA/Goddard/SDO AIA Team

Quite a bit different from my filtered visible-light image from March 24, isn’t it? Each colour represents a different wavelength of extreme ultraviolet radiation (the SDO’s AIA instrument measures 10 wavelength bands), each corresponding to a different temperature.

And here’s a solar prominence eruption measured by the same instrument, from the SDO’s YouTube channel:

Launched into a geosynchronous orbit around the Earth on February 11, the SDO measures the sun both at high resolution and at a high data rate: the spacecraft is able to beam 1.5 TB of data back to Earth every day (Sky and Telescope, Universe Today).

(Image credit: NASA/Goddard/SDO AIA Team.)

The latest iteration of snake oil

This Maclean’s story about a new skin cream based on the paralytic characteristics of the venom of Wagler’s Pit Viper, Tropidolaemus wagleri, caught my attention — another beneficial (or at least commercial) application of snake venom — yay! Go snakes! Well, not quite. Euoko markets Y-30 Intense Lift Concentrate, which costs $525 for 30 ml, as an alternative to Botox injections. It sounds more innocuous than Botox, but I wonder about its efficacy. The article soft-pedals the results from Euoko’s study:

Forty-five female volunteers, aged between 40 to 60, were told to use the cream twice daily for 28 days. Some were given the snake venom cream, others another anti-aging cream, and some a placebo. The product seemed to work well — using a highly sensitive camera, the scientists measured a 73 per cent improvement of forehead wrinkles. But then again, the placebo had almost the same success rate (71 per cent) as did the other anti-aging cream (73 per cent). Even in a lab report, it seems, beauty can be in the eye of the beholder.

If you get the same results with a placebo and another anti-aging cream, then there’s no advantage to adding the venom: it looks like you’re paying five hundred bucks for moisturizing cream. I suppose that buying jars of bullshit at exorbitant rates is the status quo for cosmetics; I’m just sad that said bullshit isn’t called out more often (and I know why the media doesn’t do it).

Not only that, the product doesn’t actually contain any real snake venom in it, so there isn’t even that exotic justification for the price: “Rather than use the toxin straight from the viper’s fangs, Euoko contracted a pharmaceutical company in Switzerland to produce the synthetic equivalent.” Right — and artificial vanillin is the equivalent of a real vanilla bean.

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After Ad Astra

So I’ve been mostly quiet for the past week. Though it took a while to screw my head back on afterward, we had a great time at Ad Astra. For our first science fiction convention, it went pretty well. Subscribing to Locus for more than 18 years really helped: I was not at all unprepared for what took place, how a con works, the general vibe and so forth.

Because we didn’t really know anyone, it wasn’t a social weekend for us, though we did talk up some writers and editors I didn’t know before (and bought a bunch of their books). I also didn’t take nearly as many photos as I thought I would (those I did take are here); it’s hard to be in the moment and take pictures of the moment at the same time, you know?

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Ad Astra

I mentioned before that I’d never been to a science fiction convention, despite being a lifelong fan. Despite growing up in a city with an annual con. Despite three Worldcons held in Canada (I missed Winnipeg in 1994 because I was moving, Toronto in 2003 because I was working, and Montreal in 2009 because I was exhausted). Well, I’m finally attending my first convention: Jennifer and I will be at Ad Astra this weekend. We won’t know a soul, but I think we’ll manage.

Returning to my first love

And now, an update on what I’ve been doing lately. (Which, as you will see, also ends up recapping the last 24 years of my life.)

In December, I finished my contract at Health Canada. I was asked if I’d be interested in returning some time in the new year, but I declined in a not-right-now-thanks kind of way. At the moment I’m not actively looking for another contract; having said that, if a good one came along, I’d have a hard time turning it down.

What I’m doing instead: I’m taking time off to write. And when I say write, I mean write science fiction.

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Our female red-sided garter has died

Remember the female Red-sided Garter Snake that gave us such a scare last October? We found her dead in her cage this afternoon, after we came back from a walk. No idea how it happened. This is a little on the premature side: she would have been eight years old in June.

We’re fond of our snakes, but she was a little bit special. She was the last female in our possession from that 2002 litter of 42 produced by Big Momma (died 2002) and Piss-Boy (died 2008). She was a stunner, the spitting image of her mother; unfortunately I don’t have any good pictures of her. (She shared a cage with our female blue-striped garter, and they made a pretty pair.) Like her father, she was extremely alert, gregarious and inquisitive; like her mother, she was extremely tame; she was probably the tamest garter snake in our collection — and that’s saying something. (Her two brothers — the last of that litter in our care — are merely voracious: they don’t mean you any harm, they’re just trying to eat you.)

When it comes to snakes in our collection dying on us, it’s never the ones we expect. There are at least four garter snakes in our care that I would have predicted to die before her: Extrovert, the female wandering garter, is 11 years old this year; Monster, the male flame garter, will be 10; the Butler’s garter, who I believe holds the captive longevity record, will also be 10 — and George, the broken plains garter, is still not dead.

Books read: March 2010

Here’s what I read in March:

Book covers for books read in March 2010 Time for the Stars by Robert A. Heinlein (1956): classic juvenile science fiction novel about twins who maintain contact over great distances as a means of communication while one serves on an interstellar exploration crew; if nothing else, a classic use of special relativity as a plot point, with the usual tropes and touches you’d expect from one of the better Heinlein juveniles.

The Two-Ocean War: A Short History of the United States Navy in the Second World War by Samuel Eliot Morison (1963). I was interested in reading about World War II naval history, and Morison’s short history seemed a natural place to start; Morison was the U.S. navy’s official historian during the war, eventually publishing a 15-volume history, and saw combat while serving on a number of vessels. I have to say I was disappointed: Morison’s history is all battles, strategy and operations, very much a top-down history — useful, I suppose, to Naval Academy students, but leaving me and my social-history training wanting more.

Ghost Train to the Eastern Star by Paul Theroux (2008): Theroux revisits the route he took for the book that made his bones as a travel writer, The Great Railway Bazaar, though the route has changed with the times, avoiding Iran and allowing Hanoi, for example. Typical or vintage Theroux, depending on how you look at it: he’s always much more interested in people than in landscapes, and he’s always chatting up writers along the way. If anything he seems less acerbic this time; maybe he’s mellowed in his fogeyhood.

Time for the Stars by Robert A. Heinlein
The Two-Ocean War by Samuel Eliot Morison
Ghost Train to the Eastern Star by Paul Theroux

Orion’s iPhone app

Orion has announced its StarSeek astronomy app for the iPhone and iPod touch; it’s almost certainly a rebadged version of Carina Software’s SkyVoyager, which I have. It also looks like they’re rebadging the Wi-Fi telescope control module I blogged about in February (Carina’s, Orion’s). I wonder if SkyVoyager and StarSeek will simultaneously coexist — might be confusing — or if StarSeek will supplant SkyVoyager. In amateur astronomy, where the same product is sold under a half-dozen brand names at the same time — sometimes at different price points! — I wouldn’t bet against the former.

First looks at iPad apps

Even though the iPad only goes on sale today, and then only in the U.S., and then just the Wi-Fi-only model, a number of apps for the gadget are already available, and several sites have been pointing to a bunch that look interesting: Appolicious, Gizmodo, Wired. I have to say that some of these look good enough to sell iPads by themselves, just so that people can use these things. It’s calling, the Precious is calling …

On the other hand, I note that a number of iPad apps are more expensive than their iPhone/iPod touch counterparts (e.g., $10 instead of $5), as though developers are trying to reset expectations this time around so that people don’t consider apps the same way they do ringtones or songs, and only expect to pay a buck or two for them. The worst trend would be something I saw a couple of months ago: a $2 iPhone app to access a website that is normally free, but which blocks iPhone users to ensure that they pay for the $2 app. Things will not go well if users think that developers are just trying to fleece them.

Sir George Head, OBE

It was only yesterday, when we tried out Google Street View’s new 3D mode yesterday, using the 3D glasses that came with the Coraline DVD, that I discovered that 3D has no effect on me — I can’t see it. My eyes are odd: my right eye is strongly dominant; to see through my left eye, I have to switch over to it. I see through one or the other, but I can’t really do both at the same time, which makes binocular vision a theoretical concept and depth perception a matter of blind guesswork. (This is why I could never catch a baseball.) With the 3D glasses, my left eye saw monochrome; my right eye saw both 3D layers. Jennifer, on the other hand, saw depth immediately and easily.

I suppose this sucks, but I’ve never known any other kind of vision — I don’t know what I’m missing. On the bright side, this means that there is absolutely no point to my paying extra to see 3D versions of movies. Nor is there any point in my buying, say, a binocular viewer for telescopes like this one, which would have required having two of each eyepiece. This is saving me money!

Epimetheus and Janus

Cruising Past Janus

Check out this series of images, taken a bit more than a minute apart, of Saturn’s moon Epimetheus passing in front of its sister moon, Janus, from the perspective of the Cassini spaceprobe, which took these images on February 14, 2010. Cassini has photographed Saturnian moons passing in front of one another before; what’s neat about this is that Epimetheus and Janus are rather close in size — Janus is 179 km across, Epimetheus 113 km — and distance: they were only 15,000 km away from another at this point. They essentially share the same orbit, swapping the higher and lower positions every four years or so as they exchange momentum. The Planetary Society has a page explaining the complicated orbital mechanics of Epimetheus and Janus’ shared orbit.

Oh shit, here comes the iPad

iPad. Image credit: Apple A media embargo must have been lifted last night: all at once, major reviews of the iPad appeared, from reviewers who were given review units a week ago. Whatever you think about whether such arrangements tend to encourage favourable reviews to ensure continued favoured access, those reviews were all very favourable — so much so that you’d think they’d be embarrassed and ashamed if they weren’t completely sincere. Here they are: the Chicago Sun-Times’s Andy Ihnatko, the Wall Street Journal’s Walt Mossberg, the New York Times’s David Pogue, and USA Today’s Ed Baig. Here, too, are Xeni Jardin at Boing Boing and Stephen Fry writing for Time. They’re all blown away by this thing.

Personally, I’m afraid of it. It will be very hard for me to resist getting one, despite the fact that I already have an iPod touch (first generation — gee, it’s looking old), a MacBook Pro and an iMac (both bought last year).

For me, the use case for mobile computing would be stronger if I were more, well, mobile. It’s why I don’t have an iPhone: my cellphone requirements are usually minimal, at least as far as voice calls are concerned, unless I’m working in the city or travelling. But ubiquitous Internet access, without worrying about open Wi-Fi access points, has always been compelling to me, so I’m gravitating to the 3G models; my iTunes library is already bigger than my 32 GB iPod touch, so I’m running the risk of the most expensive iPad model there is, the 64 GB model with 3G wireless. Not cheap!

The wireless data offered by the 3G models without the need for an expensive cellphone contract, at least in the U.S., is extremely appealing; if the Canadian iPad data plans are anything like those offered by AT&T in the U.S., I’m in trouble. In particular, the idea of what this combination of a large screen, GPS, and ubiquitous Internet access will do for maps is making me quiver. That’s a use case I have a hard time resisting. Damn.

I’m actually hoping that the Canadian mobile operators will be their usual selves and screw this up, so that I will be able to resist this thing a little longer.

You’ll know I’m doomed if you see me in an Apple Store after the iPad’s release, fondling one while repeating to myself, over and over again, “oh shit, oh shit, oh shit” — that’s what I sound like just before handing over my credit card for something I tried to resist, but failed.

(Image courtesy of Apple. First review link roundups at Cult of Mac, Daring Fireball and Kottke.)