Notes for Em


Time lapse of lightfoil in motion.I’m going to have to become some sort of physicist. Damn. I hate math.

No, actually, I don’t; I’m just a pathetic mathematician. Or, more accurately, not a mathematician at all. But that’s beside the point. Except, damn. I’m going to have to become some sort of physicist.

I suppose I shouldn’t be surprised. Some of the questions my brother and I asked thirty years ago probably astounded my father the way my daughter can absolutely befuddle me. “What,” she asked, not too long ago, “is a solar sail?”

Seven, by the way. Now eight.

Of course I told her about this far-flung idea of using a laser to push a spacecraft, and how the vessel could reach speeds near light. You know, stuff from fifteen years ago.

But I had no idea.

A BBC article brings me up to speed with lightfoil, which is a cool word despite the fact that no superhero will ever use it as a name:

Just as air causes lift on the wings of an aeroplane, light can do the same trick, researchers have said.

The effect, first shown in simulations, was proven by showing it in action on tiny glass rods.

Like the aerofoil concept of wings, the approach, published in Nature Photonics, works by making use of the radiation pressure of light.

The results are of interest for steering “solar sails”, a spacecraft propulsion based on the same force.

Each photon – or packet of light – carries its own momentum, and this “lightfoil” works by gathering the momentum of light as it passes through a material.

This radiation pressure has been considered as a fuel-free source of propulsion for long-distance space missions; a “solar sail” gathering up the momentum of the Sun’s rays can get a spacecraft up to a significant fraction of the speed of light.

But until now, no one thought to use the pressure in an analogue of an aerofoil, said Grover Swarzlander of the Rochester Institute of Technology (RIT).

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Cool science stuff


So, anyway, I was impressed over the weekend at how many people asked me whether I had heard about the octopus and the coconut. It’s one of those nifty things science brings us from time to time. Dr. Julian Finn, to the one, told BBC’s Rebecca Morelle he “nearly drowned laughing” when he first witnessed the behavior. But I admit I like Brendan Kiley‘s description for Slog:

An octopus goes for a walk.Octopuses continue their long tradition of freaking out human beings—now they’re using tools, excavating buried coconut halves (discarded by humans), tucking them under their … undersides, and “stilt-walking” them away to use as shelter ….

…. They escape from their aquariums, they grab birds from the land and into tidal pools, they solve puzzles, they recognize human faces, they occasionally attack divers, and now they build little houses for themselves.

Maybe the Haida were right all along: Octopuses are the people of the sea.

I just think it’s cool that we can add them to the list of tool-using animals. But, as with the crows, there is something a little unsettling about an animal that both uses tools and remembers who you are.

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Hefty, hefty, hefty ….


This is worth a note. Dennis Overbye reports for The New York Times:

An international team of physicists working in the bottom of an old iron mine in Minnesota said Thursday that they might have registered the first faint hints of a ghostly sea of subatomic particles known as dark matter long thought to permeate the cosmos.

The particles showed as two tiny pulses of heat deposited over the course of two years in chunks of germanium and silicon that had been cooled to a temperature near absolute zero. But, the scientists said, there was more than a 20 percent chance that the pulses were caused by fluctuations in the background radioactivity of their cavern, so the results were tantalizing, but not definitive.

Gordon Kane, a physicist from the University of Michigan, called the results “inconclusive, sadly,” adding, “It seems likely it is dark matter detection, but no proof.”

Dr. Kane said results from bigger and thus more sensitive experiments would be available in a couple of months.

Apparently this is a big deal. Dr. Kane described “a high level of serious hysteria” at the Kalvi Intitute for Theoretical Physics, in California. I mean, you know, a bunch of geeks getting hysterical at something that is … er … well beyond my context.

So, yeah. Sounds cool.

Astronomy domine, or, “Hello”


Cassini - Saturn Eclipse

I adore this picture.

If you want a photographic critique, I suppose I could say the exaggerated colors make it look like a really cool scene from an anime, but that’s not it. Besides, how do I make a proper critique of an image shot from 1.3 million miles away from its object? By a robot? Flying through outer space? A billion miles from home?

But speaking of home, if you look just inside the G ring to the left of Saturn, you might see a tiny dot.

That’s Earth. Home. Us. From nearly a billion miles away.

How can I not adore this picture?
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