Technology

At every point in space, there is something we call the “electric field.” It’s a tiny vector, a quantity with a magnitude and a direction. If you want to measure it, just put an electron at rest at that point, and watch it start moving. The direction and size of its acceleration (over and above what we get from gravity) is proportional to the electric field. Typically, if you watch closely enough, you’ll see our little electron jiggle back and forth like mad. That’s because the electric field doesn’t just sit there; we are surrounded by an extraordinary superposition of all kinds of electromagnetic waves, pushing by us with different amplitudes and directions and frequencies. If you build the right type of gizmo with an appropriate collection of electrons, you can pick out just a single wavelength from amidst the cacophony. Voila! You are listening in on the electromagnetic spectrum.

In the modern world, there are an awful lot of devices out there communicating by shooting electromagnetic waves at each other. In particular in the radio frequency range (roughly between 10 kHz and 300 GHz), which has the nice property that its waves aren’t blocked by annoying things like walls or air. This means that everyone building such devices wants to produce waves at some part of the spectrum, and that in turn means that the right to do so is an extraordinarily valuable commodity. In the US, the Federal Communications Commission gets to decide who can do what at various different radio frequencies.

This state of affairs has come into the news once again, as wireless carrier AT&T has swallowed competitor T-Mobile; many people would be unsurprised if Verizon counters by swallowing Sprint, leaving us with a duopoly and possibly giving consumers the squeeze. Currently big chunk of spectrum is allocated to broadcast TV, which some are arguing is a waste, since you could stick a lot of mobile data devices in there and everyone has cable anyway.

All very fascinating, but somewhat over my head. I’m more of a theoretical kind of guy. I just wanted an excuse to link to this gorgeous chart (pdf), showing how the spectrum is currently allocated.

Click for much bigger and more legible pdf version. There’s a lot going on here; see the zoom-in of a tiny region near 30 GHz:

Nice to see that there is space carved out for scientific research, including radio astronomy. Those jiggling electrons have a lot of work to do, let’s hope they can keep everything straight.

Only one thought, actually: why don’t I have one? Don’t they know I’m a highly influential blogger?

Via Tom Levenson:

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We occasionally joke about the looming robot menace, but seriously. Discoblog has picked out the Niftiest Robots of 2009, but “Scariest” would have been an equally appropriate appellation.

Yes, there is a robot that crawls around inside your colon, not to mention a Japanese emobot, but the one I would least like to meet in a dark alley is Chembot. It’s a blob-shaped thing that uses jamming in granular materials to make a robot that can alter its shape.

Still pretty primitive, but you can see where we’re headed here. Don’t say we didn’t warn you.

Here at Discover Media LLC, we are dedicated to bringing you news of the cutting-edge technology that will change your life. So we dispatched our Cosmic Variance automotive editor (me) to test-drive the car of the future: the all-electric Tesla Roadster. (No real secret actually; I have a friend who owns the car.) Thus, yesterday’s picture.

Fancy titles notwithstanding, I’m by no means a true car nut, so I can’t offer the insider perspective of a real expert. My take is that of an ordinary person who just had a chance to drive an exotic car through the hills north of San Francisco. After considering the experience carefully, my considered judgment could be expressed as follows: pretty frikkin’ awesome.

Let’s get some basics out of the way: the Tesla, with a body based on the Lotus Elise, is a tiny car — a two-seater with a trunk that can at best be described as decorative. And it’s low to the ground; climbing inside is a bit of a process for the uninitiated. Inside, the electronics are all state-of-the-art (as one might expect), but the Roadster is not a cushy luxury car. It’s not uncomfortable, but you’re not being coddled by piles of plush leather. Removing the convertible soft top is a matter of unsnapping and stowing by hand; takes just a few seconds, but we’re not talking about a top-of-the-line Mercedes where there are separate buttons to stow the top, clean your sunglasses, and freshen your martini. The Tesla experience is about the driving; fripperies are for future incarnations.

So you sit down, turn the key to start the engine, and: nothing. That’s to be expected, and should be familiar to anyone who has driven a Prius or other hybrid. The electric motor doesn’t need to be turning when the car isn’t moving, so turning the vehicle on just means some lights come on. Spooky at first, but you get used to it.

Actually pulling out into the road and driving is a different story. There are basically three things that distinguish the Tesla driving experience from that of your typical Ford Taurus or what have you. First, as you may have heard, the Tesla doesn’t believe in a little thing called a “transmission.” Technically, there is a transmission, but really it’s just a reduction mechanism that translates a certain number of motor revolutions to a certain fixed number of tire revolutions — there are no gears, so there is no shifting, manual or otherwise. The original plans called for a two-speed transmission, but it proved unreliable, so they said screw it, let’s just have one gear. As a result, the rate at which the motor is turning is directly proportional to the rate at which your car is moving. That includes reverse; when you’re backing up, the motor is spinning in the opposite sense from when you’re moving forward. In a conventional car with an automatic transmission, there can be a bit of a delay between when you push down on the accelerator and when you actually accelerate, as the car tries to decide what gear it should be in. No such hesitation in the Tesla.

The second thing, which you may not have heard, is that there is no power steering. I don’t know whether that was a matter of cutting down on weight, or whether it was just thought that power steering wouldn’t be keeping it real. But despite its diminutive profile, the Tesla is not a light car, coming in at about 2,700 pounds — a third of that in the form of batteries. (The Elise, in comparison, is only about 2,000 pounds; but a Mazda Miata comes in at 2,500 pounds and a BMW Z4 at 3,200 pounds, so the Tesla isn’t unreasonable.) To those of us who have gotten used to having the car practically steer for us, the Tesla is a bit of an adjustment. But the adjustment happens quickly, and it’s very much in keeping with the sporty nature of the car — you’re here for performance, not coddling.

The single gear and the lack of power steering combine to create an effect I hadn’t really anticipated before the drive: a visceral connection between the driver and the ground. It’s hard to imagine a driving experience that is on the one hand that fast, and on the other hand features so little mediation between what you do at the controls and how the car responds. The engine turns, and the car zips along, at precisely the speed you tell it to, no more, no less; and the wheels turn at an angle precisely proportional to the attitude of the steering wheel in your hands. You are in control.

And — to come to the third crucial distinguishing feature — you’re in control of a lot. …

Test Drive: Tesla RoadsterRead More »