Friction is actually your enemy here. When rockets launch they tend to go up first. That way they get above most of the atmosphere before they really start packing on the speed. That avoids a lot of atmospheric friction (which goes up with the cube of speed doesn't it?) and the huge amount of heat it generates. In the case of a gun your projectile is going at maximum speed out of the barrel, where the air is thickest, and slows down from there. There's actually another problem - from a friction point of view, the ideal is to have your gun pointing straight up. From a getting the most useful energy from the gun point of view it's best to have it aiming right along the surface. The higher you elevate it the less atmosphere you have to go through but the more work your rocket has to do.
You do have to carry a rocket with you, and guidance electronics, including some way to orient yourself. Normally that's trivial, but it's not trivial to harden that stuff against the huge acceleration and the heat. Not that you can't do it, but it's not as easy as building a maneuvering rocket designed to take 8 gees from a normal rocket launch.
The best solution might be to go easy with the gun. Don't try to get orbital velocity out of it, never mind 13,000 mph, but just aim for taking some of the load off your rocket. If you make the barrel really long you can keep the acceleration down and make a lot of problems much easier. The other good idea is to run the thing up the side of a mountain. That gets you above most of the atmosphere to start with.
Also: orbits that intersect the surface tend to do so only once.;)
13,000 mph is plenty fast enough but you can't put something into a stable orbit with a gun. You need a booster on the projectile to circularize it's orbit anyway.
You have to shoot a rocket from a canon anyway. If you don't, you just end up shooting yourself in the back. You can't put something in orbit solely with a gun.
There is the little matter of finding something to make a space elevator out of. Nobody knows how to make a nanotube cable strong enough to do the job.
I guess that's more a materials science challenge than an engineering one, but it certainly hasn't proven to be easy to solve.
That was kinda the point. Students with actual disabilities were quite capable of letting the professor know without a little box on the course outline telling them to do so.
Good to see your sense of humour is in prime form.
There have been quite a few American citizens right here on Slashdot who've posted in response to political stories something along the lines of "well, time to move to Canada."
Would you say they're credible threats to a superpower too?
Yes. In that way China is just like most large corporations. The rest of the world's companies should feel right at home and want to do business there.
That's a long way from a corporation challenging a superpower. It's also awfully speculative. Google doesn't have as much to gain by operating in China as others do, and their particular business makes it quite a bit more difficult to do so.
Do you really think the west's appetite for cheap stuff made by cheap labor in China is going to dry up? A company ordering product from China doesn't have to do any complicated filtering or anything, and there is considerable incentive for them to keep doing business with China.
True - that's why I said "depending on the circumstances." Metastudies that draw together data from experiments that were not designed to answer the current question, or are sensitive to differing or ill-reported methodology are always a little suspect. On the other hand, as you point out, metastudies of clinical trails, where all the source experiments are designed to answer the same question, are generally better than any one primary study.
It sounds like these guys have just reanalyzed Monsanto's data, which is scientifically fine. From a very quick scan of the paper, although they sexed up the abstract, it sounds like their main finding is that the Monsanto testing is inadequate to reasonably show the corn is safe, and the original analysis was done kind of sloppily anyway. As an incidental finding, they show some weak evidence that the corn might actually be having some negative effects.
I don't have time to do the math at the moment, but don't forget you have to scan the thing, which means you need a brighter laser. On the other hand, I can't think of a reason why the energy deposition should be any higher than it would be for the electron beam in a CRT.
Meta studies are scientific, though, depending on the circumstances, they may not be as good evidence as a primary study.
Studies where you reanalyze someone else's data are quite common, and are the reason there have been efforts to create large, generally available datasets including cancer registries, pharmaceutical trials and astronomical surveys.
Having food crops suffused with poorly tested pesticides sounds like overuse to me.
It does sound like the GP might have been referring to the roundup resistance, but his statement is accurate regarding built in pesticide production as well.
"Suppose someone goofs and directs the beam onto a kindergarten and leaves it there for a week. What then?"
I expect someone would figure it out when people started calling in complaining that their electricity was out.
These things are generally not planned for the middle of cities either. In order to transfer a reasonable amount of power in a low density beam you need lots of receiver area. So you build it out in the desert.
I expect they just throw up a DirectX window and call the accelerated video player function. It's not like they're rendering anything other than video, like a game would be.
So "moving to DirectX" probably involves a very small amount of code.
Slashdot Mirror
Friction is actually your enemy here. When rockets launch they tend to go up first. That way they get above most of the atmosphere before they really start packing on the speed. That avoids a lot of atmospheric friction (which goes up with the cube of speed doesn't it?) and the huge amount of heat it generates. In the case of a gun your projectile is going at maximum speed out of the barrel, where the air is thickest, and slows down from there. There's actually another problem - from a friction point of view, the ideal is to have your gun pointing straight up. From a getting the most useful energy from the gun point of view it's best to have it aiming right along the surface. The higher you elevate it the less atmosphere you have to go through but the more work your rocket has to do.
You do have to carry a rocket with you, and guidance electronics, including some way to orient yourself. Normally that's trivial, but it's not trivial to harden that stuff against the huge acceleration and the heat. Not that you can't do it, but it's not as easy as building a maneuvering rocket designed to take 8 gees from a normal rocket launch.
The best solution might be to go easy with the gun. Don't try to get orbital velocity out of it, never mind 13,000 mph, but just aim for taking some of the load off your rocket. If you make the barrel really long you can keep the acceleration down and make a lot of problems much easier. The other good idea is to run the thing up the side of a mountain. That gets you above most of the atmosphere to start with.
Also: orbits that intersect the surface tend to do so only once. ;)
13,000 mph is plenty fast enough but you can't put something into a stable orbit with a gun. You need a booster on the projectile to circularize it's orbit anyway.
You have to shoot a rocket from a canon anyway. If you don't, you just end up shooting yourself in the back. You can't put something in orbit solely with a gun.
There is the little matter of finding something to make a space elevator out of. Nobody knows how to make a nanotube cable strong enough to do the job.
I guess that's more a materials science challenge than an engineering one, but it certainly hasn't proven to be easy to solve.
It gets a little chillier. People will survive. We have made it through an ice age.
I love those arguments. Both god and the devil are trying to screw with you, and it's equally plausible that they're doing so in the same way.
Do you think they go out for a beer afterward and congratulate each other?
That was kinda the point. Students with actual disabilities were quite capable of letting the professor know without a little box on the course outline telling them to do so.
Good to see your sense of humour is in prime form.
It doesn't usually get modded funny though. Apparently the newbies all got mod points too.
Did the Onion use paragraphs?
There have been quite a few American citizens right here on Slashdot who've posted in response to political stories something along the lines of "well, time to move to Canada."
Would you say they're credible threats to a superpower too?
Yes. In that way China is just like most large corporations. The rest of the world's companies should feel right at home and want to do business there.
Interesting. We used to do that without being told to.
For example: uh, professor, I have an, um, medical thing I have to do the day of the exam. Do you think I could write it next week instead?
If you're in charge you do whatever you want.
That's a long way from a corporation challenging a superpower. It's also awfully speculative. Google doesn't have as much to gain by operating in China as others do, and their particular business makes it quite a bit more difficult to do so.
Do you really think the west's appetite for cheap stuff made by cheap labor in China is going to dry up? A company ordering product from China doesn't have to do any complicated filtering or anything, and there is considerable incentive for them to keep doing business with China.
How is Google credibly threatening China?
Google: If you don't quit trying to hack us we're leaving.
China: Finally, we can block that frakking western search engine properly.
True - that's why I said "depending on the circumstances." Metastudies that draw together data from experiments that were not designed to answer the current question, or are sensitive to differing or ill-reported methodology are always a little suspect. On the other hand, as you point out, metastudies of clinical trails, where all the source experiments are designed to answer the same question, are generally better than any one primary study.
It sounds like these guys have just reanalyzed Monsanto's data, which is scientifically fine. From a very quick scan of the paper, although they sexed up the abstract, it sounds like their main finding is that the Monsanto testing is inadequate to reasonably show the corn is safe, and the original analysis was done kind of sloppily anyway. As an incidental finding, they show some weak evidence that the corn might actually be having some negative effects.
I don't have time to do the math at the moment, but don't forget you have to scan the thing, which means you need a brighter laser. On the other hand, I can't think of a reason why the energy deposition should be any higher than it would be for the electron beam in a CRT.
Ah, see the summary says "can be detected." It can be. We've done it. You're thinking "will be detected," which nobody said anything about.
I have lots of neighbours. They should last for months.
Meta studies are scientific, though, depending on the circumstances, they may not be as good evidence as a primary study.
Studies where you reanalyze someone else's data are quite common, and are the reason there have been efforts to create large, generally available datasets including cancer registries, pharmaceutical trials and astronomical surveys.
Having food crops suffused with poorly tested pesticides sounds like overuse to me.
It does sound like the GP might have been referring to the roundup resistance, but his statement is accurate regarding built in pesticide production as well.
The local radio station is about a hundred kilowatts. That's a decent amount of power.
What you mean is that any device that radiates enough energy in one of the unlicensed bands would be illegal.
"Suppose someone goofs and directs the beam onto a kindergarten and leaves it there for a week. What then?"
I expect someone would figure it out when people started calling in complaining that their electricity was out.
These things are generally not planned for the middle of cities either. In order to transfer a reasonable amount of power in a low density beam you need lots of receiver area. So you build it out in the desert.
I expect they just throw up a DirectX window and call the accelerated video player function. It's not like they're rendering anything other than video, like a game would be.
So "moving to DirectX" probably involves a very small amount of code.
Huh, so if Google is recouping the entire phone-with-contract discount, what exactly is T-Mobile's ETF for?