It is true that you need a minimum critical mass to initiate the chain reaction, but no law guarantees that all of that material has to fission before the device blows itself apart, into a several sub-critical pieces.

I don't reveal it anymore. I have learned the hard way that, in Tucson, when you get stopped around midnight for a wide left turn sobriety check, and you let the cop know that you are armed, you get ticketed for the wide turn. Declaring it is thankfully voluntary in AZ.

If having stored equations on a calculator made that much difference on a physics exam, your instructor was doing it wrong.

Being able to go to court isn't even a guarantee anymore.

Not quite. Where was the sensor located? The front fender would have decelerated much, much, faster than anything in the cabin, behind the crumple zone. The acceleration of a component/occupant is roughly inversely proportional to the distance it travels after impact. The cabin might get three feet closer to the object of the collision, but something mounted far forward of the firewall might move inches.

Glowing is indicative only of temperature; no combustion is necessary. Look up Planck's Law. Red-hot steel is not undergoing combustion as it is being worked.

The red light cameras are why this is such a horrible idea. As it stands, they mail you a ticket which you can just throw away, because that does not count as a formal service, and they have so many to deal with that they are unlikely to send someone to your house. If a light goes off in a bored cops car because someone 100 yards ahead has an unserved photo radar citation, you are now going to court. There may also be alerts for sex offenders, previous DUI convicts, etc.

I have always thought that to be primarily the fault of the students. Of course, practices such as allowing "equation sheets" greatly encourage this sort of thinking among the students. Why waste effort stitching everything together in your head when you can start every problem just two or three algebraic steps away from the answer, clear the burdening requirement with a C, and move on to become a terrible engineering student?

I did not mean precisely at the critical point, just that the entire body of the pilot should not be dramatically displaced. I still think that the critically stable point is a reasonable goal, considering that the computer can continually adjust the individual motors to keep the thing upright, and there is no gravitational torque to continually fight for any ground speed. A free gimbal would demand that the motors be powerful enough to correct for chaotic forces from a swinging 100KG mass in addition to maintaining normal flight, and an active gimbal would add a lot of unnecessary weight, and I doubt that would be more efficient.

It is hard to guess from that picture where the actual center of mass is anyway, since the power source is likely contained in that bulb under the pilot, but it looks to me like the goal was to keep the center of mass near the plane of the rotors, and this seems like the simplest and most efficient design considering that all rotors are under computer control anyway.

That would make it more stable, but harder to maneuver. With the center of mass in the plane of the rotors, it only takes very slight modifications to the torque to rotate it, and is probably the more power efficient way to do it. There is much more micromanaging of the controls to keep it level this way, but this is all done by computer and the pilot is fucked in any case if the computer fails.

It has been a while since I was obsessing over this stuff as a kid, but I believe that was one of the innovations behind the F-16 when it was introduced. It was so unstable that a human could not fly it; the manual controls were essentially a DC offset on the rapid control from the computer. This made it incredibly maneuverable.

Clearly you don't drive on weekends between midnight and 3 am, during which time I have been stopped for failing to signal, wide turns, and even because "at first I thought your tail lights were out but I guess they are just a little dim." Of course all of these were accompanied by sobriety checks. I was once late for the first day of a new job after a cop pulled me out of morning rush hour traffic to cite me for having a 12-inch crack in my windshield. I am curious where you live.

I think I somehow parsed "was no warming happening before humans arrived" as something like "would be no warming in the absence of humans." That's what I get for reading slashdot while thinking about the physics I was working on in the other window.

In that case, my point would have been that accelerating and causing are two very different roles. Perhaps a better term would be human-augmented global warming.

You should look up the word "anthropogenic".

I was not saying that these jobs are or will be a sizable fraction of the total number of jobs in the economy, just that the fraction does not monotonically decrease with population so devastatingly. I see no argument here as to why the number of jobs will not roughly scale according to demand. Microsoft has 100K employees because a growing demand provided increased revenue that allowed them to hire more specialists, to increase functionality (maybe MS is a bad example here) on a variety of fronts.

The absolute number of jobs does not generally increase so that you can throw more people on the same problem; it increases so that a larger number of issues can be addressed simultaneously, ideally to strive to offer greater functionality than competing products. As the demand increases, the increasing revenues facilitate this, even if no additional labor is required to distribute the service to a larger base.

You mentioned solar. You would be amazed how many varieties of photo-voltaics are out there, as well as the variety of niches for such things. Different manufacturers, technologies, and variations on fabrication processes have created products that widely span both spectra of power per unit area and power per installation cost. A customer's specific configuration of available area and budget will point them to specific manufacturers of a specific technologies; there a therefore many fronts for healthy competition. There is also a lot of variety in the mounting methods. Solyndra had a clever rack of cylinders that offered minimal stress to the mount under high wind loads. Many companies are working on "building integrated photo-voltaics" with lots of variety regarding partial shading performance, fire risks, installation costs, etc. These peripheral innovations, after the core invention, demand constant research and development work to stay competitive, and the competition in this industry is very real. There are always new fronts for additional design personnel, (much of this doesn't even require "crazy PhD types"), and more can be sustained with higher revenue streams, which follow from increased demand/population.

These arguments are all quite qualitative, as are yours, so I am not going say whether the number of design specialist opportunities is actually approximately proportional to the population, but I doubt it is too bleak. I think you would have a hard time producing any statistics that showed the fraction of the population engaged in professional research doing anything but increasing.

Of course, little of this is specifically applicable to industries dominated by abusive monopolies.

I have never studied this, but perhaps you could clarify. They are not producing a consumable product, but with everything being equal, if the population doubles, the amount of money available for design jobs doubles, and in a free market this would be more likely to fund two competing designers, rather than reward one disproportionately while nobody else tries to get in on the lucrative profession.