30c per kWh is a lot. I usually pay about 10c. Plus, access to space would give very cheap access to 24x7 solar energy, which would further reduce energy costs.
If you have a project with a more or less guaranteed return on investment, people will usually lend you the money. Besides, its easily in the range that the American government can afford- they spend 10x that per year outlay on space every year.
Besides, if you build one, you can build one for other governments, cheaper than they can build one themself. So you can defray your costs by making money that way.
I've read this paper in full, a couple of months back. According to the paper the actual, demonstrated strength of the carbon tethers is only as strong as Kevlar- it's about 1/10 of the needed strength. The overall weight of the fiber is exponentially related to the strength, so the tether works out maybe 20,000 times heavier than his design- which makes it completely uneconomic.
OTOH, single fibers are almost strong enough, but only if you allow absolutely no 'safety factor'. Most normal engineering uses atleast 2 safety factor, and usually many times that. But as nobody knows how to splice them together into a rope, and doing so would lose atleast 25% strength, it's not enough.
He's got the best architecture I've seen for this by a long way, nice paper study. Not practical right now. Hope somebody sorts out the fibers very soon.
Um. The game costs something like $10-15/month. I pay about $2/day for my ISP (yeah, I know). That means if you play it for an hour a day, it more than pays for itself.
And many people play for 80 hours a week. Clearly if they sell their character after a while then they are going to be in profit.
Its cheaper because you don't need some hairy ape running around digging and drilling and laying wires.
It's faster only if its short distance- then you can get many megabits/second. Long distance you can too, but then you take up too much bandwidth over a wide area.
Even the UWB takes up bandwidth, but because it steals such a small amount from the existing fixed bands you can mostly get away with it; and the total power is very low, and any interference is only likely to be over a short distance anyway.
Yes, but unlike guns, for SPAM to work i.e. make money, they need include real contact info in some form. So, the person/group at that contact is in big trouble if they've broken the law, as the cops can follow it home in many cases.
>If you think this didn't cost any real money, think again. I'll bet the launch space was "donated" and written off. Congratulations, the US
>Government just paid (40% corp tax rate * 500,000 secondary payload lauch fee) for this $50,000 satellite.
Actually, you have this backwards; the launch costs are the cheap bit! The cost of any satellite that gets within five times the launch costs is doing very well, this one is probably about one tenth of the launch costs. Boeing just saved a fist full of money, and it's entirely possible that the launch truly was free- rockets are rarely 100% occupied. The cost of the launch presumably was paid for by the other occupants.
There's another secret here that few people realise- the main thing that is keeping the cost of launches high is the lack of demand. The reason there is little demand is that the costs are high. Anything, like this, that can reduce the overall costs is going to have a very positive effect on the launch market, price, volume and profit.
Actually they went to Boeing, and said- hey we need $50,000; Boeing looked at the plan, it looked good, so they patted them on the head, and gave them $250,000, figuring they would need it- and then the students came in on their original budget...
So, the university now has funding for the next 4 years.
There were no salaries- this satellite was built using student labour.
The satellite was launched for free of course, there was space on one of the launchers for it, and they weren't charged AFAIK.
Incidentally, radio hams have put their own satellite up... so its not totally out of the question for privately funded groups.
>GR doesn't have any kind of description of "the motion of space".
To a first approximation it does, or they are trivial to construct. Draw the light cone of a body at rest relative to a gravitating body. You can define that as a motion of space. It's not normally described that way.
The curvature of space is a bit similar to the curvature of the water surface in a waterfall or a whirlpool, but as you note the analogy is not exact. (NO analogy is exact, by definition).
Nortel's Contivity product supports this. The normal idea is that you use it across the internet, but you can use it on a totally insecure wireless like ieee802.11b.
> It doesn't make sense to say that "space moves".
Perhaps, but that's pretty much what happens. Any object in the space around a gravitationally attracting mass finds that its inertial frame heads off towards the mass.
That's one effect. Another is that if the gravitating mass is rotating, it actually makes things spiral in, rather than fall straight in. I think that the idea that space moves, is a pretty reasonable approximation to what the GR equations are telling us.
You're water slide doesn't capture the second effect.
>Can't the Canadian dimplomats say, "hey, since we gave you this huge plot of prime real estate in our downtown core, we'd really appreciate it if you wouldn't cover it with spy equipment."
Yes, but the Americans would laugh. The Embassy is American soil and they can do whatever they want.
>"Also hint that next time they want to build a new embassy in Ottawa, they'll have them build it in, say, Stittsville."
Want to break off diplomatic relations?
Also, you appear to be assuming that the Canadians aren't spying on them as well.
Just because it is insecure at the wireless level, doesn't mean its insecure at the check-in level.
After all, if they have a firewall, and the wireless is on the public side of the firewall, then it should be pretty secure- the check in desks would have to use tunnelling to connect, but that can be arbitrarily well encrypted.
>Basically, as far as we could tell, (1) the "escape velocity is greater than speed of light, and nothing can go faster than light" explanation has nothing really to do with it, and
It has got something to do with it, because it is true; right? Whether that is the easiest way to explain it to layman- probably not.
To my mind a good analogy of falling into a black hole is falling over a waterfall. If your boat can go at 10 mph, and the water goes at 9 mph, you can escape, but it will take a while. If the water is going at 11 mph, you are doomed. Right?
Space near a black hole is just like the water, IT MOVES and speed of light is like the boat's speed. The water is moving, and at the event horizon it exceeds light speed. I mean sure, you can max out your speed, but that doesn't matter because you're going down.
>(2) there is no simple intuitive explanation of why you can't get out of a black hole (where "simple intuitive" means comparable to the escape velocity explanation).
Your boat can't go fast enough due to the laws of physics.
Actually, I'm not totally sure that this was the right decision. Some of the generational garbage collector schemes could have given much the same behaviour- they don't touch objects that don't change and their basic data set doesn't change.
It's not impossible in the theoretical sense; but the size of the rocket climbs exponentially with delta-v, so the rocket ends up really, really huge; really heavy and really expensive, even with multistaging.
The required delta-v here is roughly 30 km/s including earth escape. This is 3x bigger than that needed to achieve orbit. That makes the rocket exp(3)=20 times bigger than one needed to reach orbit.
Adding a running start helps quite a bit exp((30-5)/)=12 times bigger than a normal launcher, but its still way too big. Also, if you are launching a rocket 12 times bigger than, say, the Space Shuttle; that's one mother of a rail gun.
Actually I believe the issue is the executors that run MSFT (e.g. Bill) have large numbers of shares. Therefore if they start receiving dividends, they would be liable for tax. Presumably they are only liable for tax right now when they sell shares. (Roughly speaking- IANAA); and the money that the company is making gets siphoned off as much as possible to the board; and little of it is 'wasted' ending up as taxes.
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30c per kWh is a lot. I usually pay about 10c. Plus, access to space would give very cheap access to 24x7 solar energy, which would further reduce energy costs.
The tape IS wider in the middle than the ends, the tape is very skinny at either end. And his deployment strategy works fine. Read the paper.
If you have a project with a more or less guaranteed return on investment, people will usually lend you the money. Besides, its easily in the range that the American government can afford- they spend 10x that per year outlay on space every year.
Besides, if you build one, you can build one for other governments, cheaper than they can build one themself. So you can defray your costs by making money that way.
I've read this paper in full, a couple of months back. According to the paper the actual, demonstrated strength of the carbon tethers is only as strong as Kevlar- it's about 1/10 of the needed strength. The overall weight of the fiber is exponentially related to the strength, so the tether works out maybe 20,000 times heavier than his design- which makes it completely uneconomic.
OTOH, single fibers are almost strong enough, but only if you allow absolutely no 'safety factor'. Most normal engineering uses atleast 2 safety factor, and usually many times that. But as nobody knows how to splice them together into a rope, and doing so would lose atleast 25% strength, it's not enough.
He's got the best architecture I've seen for this by a long way, nice paper study. Not practical right now. Hope somebody sorts out the fibers very soon.
Yeah, perhaps in your case that would need to be the case ;-)
Maybe they took it off after someone hacked the site so that it really did collect credit card numbers, and said it hadn't ;-)
Um. The game costs something like $10-15/month. I pay about $2/day for my ISP (yeah, I know). That means if you play it for an hour a day, it more than pays for itself.
And many people play for 80 hours a week. Clearly if they sell their character after a while then they are going to be in profit.
FWIW you're close, but no cigar, actually the invariant relativistic equation is:
Dx^2 + Dy^2 + Dz^2 - Dt^2 = constant
Where Dx, Dy, Dz and Dt are distances in x,y,z,t directions.
But noone knows how to get an imaginary velocity...
It isn't just DSSS, I think the UWB bit may refer to picosecond pulses to maximise the bandwidth.
Its cheaper because you don't need some hairy ape running around digging and drilling and laying wires.
It's faster only if its short distance- then you can get many megabits/second. Long distance you can too, but then you take up too much bandwidth over a wide area.
Even the UWB takes up bandwidth, but because it steals such a small amount from the existing fixed bands you can mostly get away with it; and the total power is very low, and any interference is only likely to be over a short distance anyway.
Yes, but unlike guns, for SPAM to work i.e. make money, they need include real contact info in some form. So, the person/group at that contact is in big trouble if they've broken the law, as the cops can follow it home in many cases.
Illegal guns? You shoot, you run. No id required.
>If you think this didn't cost any real money, think again. I'll bet the launch space was "donated" and written off. Congratulations, the US
>Government just paid (40% corp tax rate * 500,000 secondary payload lauch fee) for this $50,000 satellite.
Actually, you have this backwards; the launch costs are the cheap bit! The cost of any satellite that gets within five times the launch costs is doing very well, this one is probably about one tenth of the launch costs. Boeing just saved a fist full of money, and it's entirely possible that the launch truly was free- rockets are rarely 100% occupied. The cost of the launch presumably was paid for by the other occupants.
There's another secret here that few people realise- the main thing that is keeping the cost of launches high is the lack of demand. The reason there is little demand is that the costs are high. Anything, like this, that can reduce the overall costs is going to have a very positive effect on the launch market, price, volume and profit.
Actually they went to Boeing, and said- hey we need $50,000; Boeing looked at the plan, it looked good, so they patted them on the head, and gave them $250,000, figuring they would need it- and then the students came in on their original budget...
So, the university now has funding for the next 4 years.
There were no salaries- this satellite was built using student labour.
The satellite was launched for free of course, there was space on one of the launchers for it, and they weren't charged AFAIK.
Incidentally, radio hams have put their own satellite up... so its not totally out of the question for privately funded groups.
"There is no physical observable you can write down in GR that describes "the motion of space"."
Cool, you have a non-existence proof? Excellent. I'll get the pop-corn. This should be good.
>GR doesn't have any kind of description of "the motion of space".
To a first approximation it does, or they are trivial to construct. Draw the light cone of a body at rest relative to a gravitating body. You can define that as a motion of space. It's not normally described that way.
The curvature of space is a bit similar to the curvature of the water surface in a waterfall or a whirlpool, but as you note the analogy is not exact. (NO analogy is exact, by definition).
More info:
Nortel's Contivity product supports this. The normal idea is that you use it across the internet, but you can use it on a totally insecure wireless like ieee802.11b.
See Contivity
> It doesn't make sense to say that "space moves".
Perhaps, but that's pretty much what happens. Any object in the space around a gravitationally attracting mass finds that its inertial frame heads off towards the mass.
That's one effect. Another is that if the gravitating mass is rotating, it actually makes things spiral in, rather than fall straight in. I think that the idea that space moves, is a pretty reasonable approximation to what the GR equations are telling us.
You're water slide doesn't capture the second effect.
>Can't the Canadian dimplomats say, "hey, since we gave you this huge plot of prime real estate in our downtown core, we'd really appreciate it if you wouldn't cover it with spy equipment."
Yes, but the Americans would laugh. The Embassy is American soil and they can do whatever they want.
>"Also hint that next time they want to build a new embassy in Ottawa, they'll have them build it in, say, Stittsville."
Want to break off diplomatic relations?
Also, you appear to be assuming that the Canadians aren't spying on them as well.
Just because it is insecure at the wireless level, doesn't mean its insecure at the check-in level.
After all, if they have a firewall, and the wireless is on the public side of the firewall, then it should be pretty secure- the check in desks would have to use tunnelling to connect, but that can be arbitrarily well encrypted.
>Basically, as far as we could tell, (1) the "escape velocity is greater than speed of light, and nothing can go faster than light" explanation has nothing really to do with it, and
It has got something to do with it, because it is true; right? Whether that is the easiest way to explain it to layman- probably not.
To my mind a good analogy of falling into a black hole is falling over a waterfall. If your boat can go at 10 mph, and the water goes at 9 mph, you can escape, but it will take a while. If the water is going at 11 mph, you are doomed. Right?
Space near a black hole is just like the water, IT MOVES and speed of light is like the boat's speed. The water is moving, and at the event horizon it exceeds light speed. I mean sure, you can max out your speed, but that doesn't matter because you're going down.
>(2) there is no simple intuitive explanation of why you can't get out of a black hole (where "simple intuitive" means comparable to the escape velocity explanation).
Your boat can't go fast enough due to the laws of physics.
Actually, I'm not totally sure that this was the right decision. Some of the generational garbage collector schemes could have given much the same behaviour- they don't touch objects that don't change and their basic data set doesn't change.
> Guess who gets to make the rules
The ones with no spears sticking out of their backs?
;-)
It's not impossible in the theoretical sense; but the size of the rocket climbs exponentially with delta-v, so the rocket ends up really, really huge; really heavy and really expensive, even with multistaging.
The required delta-v here is roughly 30 km/s including earth escape. This is 3x bigger than that needed to achieve orbit. That makes the rocket exp(3)=20 times bigger than one needed to reach orbit.
Adding a running start helps quite a bit exp((30-5)/)=12 times bigger than a normal launcher, but its still way too big. Also, if you are launching a rocket 12 times bigger than, say, the Space Shuttle; that's one mother of a rail gun.
Dunno; I'm guessing, but it sounds plausible. They probably give themselves share bonuses or whatever is most tax efficient at the time.
Actually I believe the issue is the executors that run MSFT (e.g. Bill) have large numbers of shares. Therefore if they start receiving dividends, they would be liable for tax. Presumably they are only liable for tax right now when they sell shares. (Roughly speaking- IANAA); and the money that the company is making gets siphoned off as much as possible to the board; and little of it is 'wasted' ending up as taxes.