Greg H.

Converting your idea into a model is relatively straightforward, but it does require relatively thorough knowledge of the existing subject matter. What does your idea say? For example, if your idea is "The speed of sound transmission varies by the density of the medium", then you would need to come up with an equation that expresses that idea. That equation could then be used to test the idea. So fir instance, your equation might be that the speed of sound in the atmosphere multiplied by the density of the object will give you the speed of sound through that object. Other scientists can then take your equation, and the known values (speed of sound and density of an object) and test your idea under controlled conditions (to eliminate other variables). if it pans out, hooray. If not, you go back to the drawing board. In the case of our example, we may find that our predictions are close, but consistently not quite right. In that case, we may go looking for some other reason why the calculations seem to be so close. (In the case of our example, the speed of sound also depends on the stiffness of the medium in question). All a "model" is in this case is a mathematical representation of what your idea is trying to express. Of course, the more complex the idea, the more complex the equation.

Actually it wouldn't take much of a change in Oxygen concentration to kill humans. The Occupational Health and Safety Administration has done quite a lot in the area of Oxygen levels in confined spaces, as it relates to worker safety. Turns out that once the oxygen content in the atmosphere drops below about 19.5%, your blood is no longer carrying as much Oxygen as it can (it's no longer at saturation). How that would affect Ozone production, I'm not entirely sure, but I have a feeling we'd have larger issues, as Strange points out. The bigger issue in terms of Ozone production is artificial depletion due to chemicals in the upper atmosphere. These artificially break up ozone molecules - effectively skipping the part where it absorbs that uv ray, which allows more of the high energy rays to reach the ground.

Take a gander at the article on the Chapman cycle. The important thing to remember is that Oxygen that combines to form Ozone isn't lost forever. Ozone can (and does) break apart to form O2 + O when exposed to the proper wavelengths of ultraviolet radiation. (This cycle also produces excess kinetic energy in the form of heat). This is how the Ozone layer does its job of protecting us from high energy uv rays - it absorbs them and breaks apart.

The riots would be interesting. As I have a digital readout in my car, I can confirm that at least some US cars do indeed have a toggle switch to change between Imperial and Metric. Sometimes I set it to metric in the winter just to mess with the kids about how cold it is outside (the car's digital outside air temp readout also changes with the toggle).

Well, true. Though I assume that's what the lead and steel wrapper is for - to keep it from irradiating the neighbors. I suppose you could call Bruce Banner in to hold onto it for you.

Then hold them responsible for it. Really, it sounds like the main issue is that there was either a lack of regulation on what to do with said device, or a lack of enforcement of that regulation. I agree that what happened should have never been alloiwed to happen, but I still fail to see what a GPS device is going to do to prevent this from happening again, unless you set up some kind of expensive system that monitors their locations and automatically summons help if they're moved. Not that this will stop people from stealing them intentionally - there are ways to block a GPS signal. It would just stop the accidental exposures as in this case.

Or we could, you know, make the people who hold those sources actually responsible for them. The fact is, the source was abandoned, on site, by the people running a private clinic, and then later taken by scavengers. Adding a GPS isn't exactly going to help in a situation like this where someone handling the device, not knowing what it is, later breaks it and releases radiation. What should happen is effective monitoring and regulations regarding disposal when a site shuts down.

This is also a good point. I was merely referencing his post in terms of hours of actual instructions - not additional time spent studying on his own. As a general rule of thumb, I tended to set aside between two and three hours per hour of classroom lecture for homework, research, papers, and study. But we also have to take into account that out of the 140 hours spent on an undergrad degree, only about half of those are actually spent on classes in the major concentration of study - the rest are core cirriculum and electives - since he is not purusing a tradiitonal route to a degree, those other requirements do not need to be met.

I doubt there would be much chaos, execept in the manufacturing world, where they would need to retool machines to use the new system. Gas would probably go up since all of the pumps would need to be reworked to charge by the liter rather than the gallon. Oh and all the old cars that would need to have their speedometers/odometers updated to account for kms travelled and km per hour - I could see this causing some angry murmurings. There would be some getting to the idea of new measurements - liter versus gallon, cm versus inch - but on the whole I think there would be more consternation and angry grumbling than outright chaos. After all, we do manage to go to places like Canada and Europe on a fairly regular basis without completely losing our cool and starting riots at this metric thingee.

Just by running the numbers - an undergraduate degree at an american university is somewhere between 120 - 140 semester hours (depending on the university). 1 semester hour is considered to be (in general) 1 hour per week for 16 weeks - so 16 hours is equivalent to semester hour, which means that your average undergraduate degree is worth about 2080 total hours With 5000 hours, you would have completed the equivalent raw hours of around 2 and 1/2 complete undergraduate degrees (which would also include other classes besides just science and math) so it should be reasonable to assume that you should have obtained a university level education in those two subjects by investing that amount of time. However - this assume that the material you are studying is actually of an appropriate level.

The milky way is about 500 billion times the mass of our sun - two orders of magnitude larger. Do you not believe in the milky way too? What you believe is inconsequential - nature is not constrained by your beliefs.

Disparaging your audience is an amazing way to get them to come 'round to your way of thinking.

Aren't those called lawyers? (I know, I know...but I had to)

I admit it, I laughed.

There are four states of matter: gas, liquid, solid, and plasma. Liquid-solid is not a state of matter, it's a transition phase - a glass of ice water, for example, is in that transition phase while the ice is melthing into the water. But the ice is not liquid, and the water is not solid. That's why the original question is poorly worded. Some parts of the human body - the bones, for example, and solid. Other parts, such as the blood, are liquid. The air in your lungs is obviously a gas. So how do you choose just one of those phases and say the human body is solid/liquid/gas? As I said originally, if I had to pick one, I would choose sollid, because that's how the body interacts with the world the majority of the time. But it's a terrible question.

I wouldn't use it as a primary source for a proper scholarly article, or a graduate level research paper, but it's OK as a spring board to help you find related information, or as a way to provide discussion points on a topic. A lot of its value to me is in finding primary sources that I may not be aware of, generally cited in the references for the wiki article. As long as you're doing your due diligence in validating sources it's not a bad place to get general information on a topic imo.

You also run into issues of economics. It's probably going to cost you more to build and maintain such a system than it would be worth based on the amount of energy generated.

So the basic gist is, if you have an hour long football game, you can heat up one cup of coffee with microphones in an hour, of in a couple of minutes with a microwave oven. I think the phrase energy density applies here.

Which is why Newtonion formulas still let us put satellites in orbit.

In retrospect you may be right - it's constant motion that's undetectable. I'm guessing that's what I meant, and I got caught up in the accelerating bit from the previous post. In any case, I should have known better. Thanks for the correction. Edit I corrected my post above.

While it may seem silly, it is mathemtaically accurate. This is what makes physics deceptively easy at first blush. A lot of it makes good sense and jives with what we experience everyday. And a lot of it seems to make absolutely no sense whatsoever, and is just as correct. This is why I often say that doing physics by common sense is the worst way to go about it. You have to actually get a grasp of what the equations are telling you. For example, in the case given by whiskers, if you had no other reference - only your rocket and a single planet - could you really PROVE which one of them was accelerating moving, if all you had to go one was the view out the window? According to the math, either case is viable - either you and your rocket are moving away from the planet, or the planet is moving away from you and your rocket. The equations make no distinction between the two cases, and will yield valid answers regardless of which case you assume. So while it may seem silly to you that a planet is wandering off away from your rocket, to a Peirson's puppeteer, that's just a Thursday afternoon. And not even a very interesting one.

Do you want to spend a couple of million of your own dollars to build a street from your house to the main road? Probably not. But by charging everyone in the area (including people who probably don't care if you have a street or not) a few cents each, your street gets built, and you get to drive to work instead of walking there. (uphill, both ways) If you did spend a couple of million of your own dollars, might you not rightly feel that it would be your due to charge other people who want to use your street, including the fire department, or the ambulance, who are trying to get to your neighbor's house? It isn't that people don't want the road. They just don't want to (or can't afford to) pay for it. That's why taxes, as irksome as they may be, are vital to sustaining the infrastructure of our society. The government amasses those contributions, centralizes them, and then allocates them in a way that will do the most common good (theoretically).

By fastidious, do you by chance mean normal? Because that's what a normal person does - makes sure they bring home the same children they left the house with. It's not even that hard - it's not like they are invisible or something.

In theory, the idea behind a centralized government is to provide those things that the society needs that individual members of society aren't really going to either want to provide, or have the means to provide on an individual level. Roads for example, or emergency services. In ancient times, the government probably oversaw agricultural activities. And of course, organized defense (or agression). Most governments also tend to get into the business of legislating morality, which is not, to my mind, the job of a government.

It seems to me you'd be better off using the fuel to propel something larger at the comet to deflect it. Not crunching the numbers, but it seems like a more efficient use of a giant pile of radioactive material.