Did you hear the one about the guy on 9/11? Probably because there was no douche bag making jokes about that!
...or the ones making the jokes are still in elementary school? I'd be surprised if ten years from now, some online forum doesn't have a thread just like this one in which the posters reminisce about all the stupid things they said that seemed funny at the time after 9/11. This is just how people remember things when they're young.
This actually is somewhat important for establishing historical data for carbon dioxide density in the atmosphere. Presumably, the new data will allow someone to extend this graph, and see where we are now relative to a million years ago.
Why in the world would you launch it? You have a space _elevator_.
You need the counterweight to build the space elevator in the first place. Once in place, newer, stronger space elevators could indeed use the original elevator to hoist new counterweights into place.
Perhaps the solution would be to require companies to put down a deposit whenever they stick something in orbit. They get it back when the object leaves orbit.
Trust me, it's much cheaper just launching new stuff at $10k/kg than to bodge together something using the junk already there.
It's called "space junk" for a reason. Some of it's probably OK, but most of it is real garbage.
I suppose that depends on the intended purpose. I don't think assembling a space station out of it is practical (at least, not without a lot of manufacturing infrastructure that we don't have in orbit right now), however, it could be used as part of a space elevator counterweight (assuming the significant orbit modification can be made more cheaply than launching a similarly heavy object from the ground), or use the debris as the reaction mass for a mass driver, or use it as a radiation shield.
Maybe if we gathered them in one place we could eventually have a new (very small) moon that could be easily tracked and avoided. I suppose it would be below the roche limit, and would thus perhaps need to be caught in a net, or a strong magnet.
Anyone care to guess which would require more delta v, deorbiting a satelite or moving it to a "designated rubbish pile"? It seems like some space debris would be salvageable, it seems a shame to drop it back into the atmosphere after spending so much fuel to get it up there in the first place.
Anyone have any good ideas for the names of aforementioned moons?
find opponents with similar skill
on
Chess for Kids?
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· Score: 1
I agree with the parent but would like to add that the best way to learn chess is to play against those with a similar level of skill. That way, no one is bored with an easy win or demoralized by inevitable defeat, and everyone gets better at roughly the same rate.
It doesn't matter how many sockets you have open, it's just as useful with one socket as many.
The argument isn't that select and poll don't work with large numbers of sockets, the problem is that they aren't scalable. Both system calls take, as an argument, a list of file descriptors the program is interested in listening to. If there are hundreds (or thousands) of sockets open, those lists can become unweildy. The scalable alternatives remember which file descriptor the process has asked to be notified about previously, rather than require that the process sends the kernel a complete list every time.
It seems a lot of Linux gui programs hang while waiting for network data - they're obviously not taking advantage of this.
I don't doubt that that's probably true in some cases. Few client programs have very many sockets open at once, so select or poll would be a good choice.
Yeah, we have that in America for major appliances (I'm not sure if it's mandatory or not). I think it should be mandatory for small devices as well. I'm often surprised by how much heat a wireless router can generate (though, this time of year I don't mind so much as it keeps my apartment warm).
By law, the label must be shown on all refrigeration and laundry appliances, dishwashers, electric ovens and lightbulb packaging.
Yes, like that, but it should be required for anything that can be plugged into the power grid, even indirectly (such as PCI cards). I like that those labels have an (unfortunately optional) noise rating - it might be nice when shopping for computer components.
I think one of the easier ways to reduce energy consumption is with labelling laws. Similar to food ingredient labelling, any electronic device sold should have a label that says:
This device uses a maximum of X watts when in use, and Y watts when idle.
This way consumers can make informed decisions when buying electronic equipment. Right now, it's hard to consider power consumption in purchasing decisions because the information is not readily available. Remember, information asymmetry is a bad thing, and tends to result in lousy (or in this case, inefficient) products.
I suppose the hard part of what you propose is separating the CO2 from the exhaust. I don't know if this is the best method, but one way is to compress the air until the CO2 liquifies. Unfortunately, this would require a lot of energy, probably more than the power plant produces by burning coal in the first place. By comparison, using algae to absorb the carbon dioxide sounds pretty good.
What happens when you burn the methanol and biodiesel? Doesn't that just release the stored CO2 and Nitrogen Oxides back into the atmosphere, or am I missing something here?
Yes, it ends up in the atmosphere in the end, but you get to use it twice. If you're going to polute, you might as well pollute in a way that maximises the energy generated per quantity of carbon dioxide produced. Also, this could partially solve a political problem of reliance on foreign fuel.
Also, if these algae are so great, why don't we fill up thousands of acres with them, not just 15,000, and suck the CO2 and Nitrogen Oxides out of the atmosphere, reducing greenhouse gasses. Maybe the algae could then be dumped into the deep ocean, creating a carbon sink.
I assume that the algae grows better in an environment with a high concentration of carbon dioxide, such as power plant exhaust. The gains from pumping regular air through an algae filter would be less dramatic (and you could probably acheive a similar result by, say, planting a tree).
Of course, the second this moves from simply audio to pictures and/or video, you could wind up with other illegal content (i.e. child porn) on your player, just by walking by someone with a similiar device who so-happens to be a pervert.
I think this could be fixed with a proper implementation. Suppose your media player knows what files you like. Perhaps the media player could periodically connect to the Internet and upload your preferences to a recommender system. The recommender system would then compare your preferences to the preferences of the other users and generate a list of files (or, better yet, a list of cryptographic hashes of files) that you have a high probability of liking. Then, when your device talks to another device, it only downloads files that were on your "good" list.
The violations of privacy that people should be concerned about are not a few tracking cookies, but are in fact a widespread and ongoing monitoring and profiling of the activities of all internet users.
I agree that this isn't a significant privacy issue. However, I think the real concern is that government websites are violating their own established privacy rules. In all these cases, it was probably an honest mistake, but people really should complain loudly any time any government agency seems to consider itself above the law.
Of course, as the article says, there aren't any rules restricting congress from using cookies, only the executive branch is restricted in this way, so the earlier story about the NSA using cookies was much more relevant in that respect.
All I'm saying is who's to really, really know if a publicly-traded company like RSA can't get "leaned on" by the government to provide the NSA with a back door?
The RSA patents have expired, and the algorithms are well understood. There's really no reason to stick with RSA's implementation.
In fact, according to Steven Levy in "Crypto" there was the possibility that the original RSA encryption would never see the light of day if users didn't surrender their keys to the government to be held "in escrow", to be made available to law enforcement with the appropriate warrant...
Fortunately for us, key escrow didn't have enough political support, and we now have crypto anarchy. (That's a very good book, by the way.) Despite what naysayers may say, we still live in a democracy, and NSA doesn't make all the decisions.
No one except the NSA really knows if the NSA has some magic box that can factor large primes, but a lot of people have worked on the problem without breaking RSA with some progress made, but no real success (assuming approprately large keys). I'd personally be more worried about the NSA (or others) tracking the source and destination of email messages, which is much more difficult to hide than the message contents -- and encryption is probably the best way of getting picked out of a crowd for additional scrutiny (which isn't to say that encryption is a bad idea, just that someone with something to hide ought to make sure their secrets aren't discoverable through some other unencrypted channel that would have been ignored if he/she haden't drawn attention to him/herself).
SSME has ~12 *million* horsepower. If you scaled up the ESA's labscale engine - its about maybe a tenth of the size - you are talking about 1,400 horsepower. There is no comparison.
I think you're comparing the 815 pound weight of Smart-1 (which is the weight of the whole probe including thrusters, fuel, batteries, scientific equipment, etc...) to the 7,774 pound weight of SSME, without fuel.
Also, the SSME is built to lift a very heavy space shuttle (and worse, its 4 million pounds of fuel) to orbit. Of course it needs a lot of power. Presumably, this new thruster does not need to carry as much propellant because it expells it at a higher velocity. If this thruster is light enough that it can lift its own weight, plus that of its propellant and energy source, then it can carry objects to orbit. It doesn't need 12 million horsepower if it doesn't weigh 4.5 million pounds.
You're probably right that it isn't strong enough, but I don't think your comparison is sound. I also agree that this would be a wonderful way to cruise around the solar system. (It might even be a good way to push heavy things like meteoroids around).
Calculations suggest that a helicon double layer thruster would take up a little more space than the main electric thruster on ESA's SMART-1 mission, yet it could potentially deliver many times more thrust at higher powers of up to 100 kW whilst giving a similar fuel efficiency.
I would hesitate to call this a "very low thrust" engine, since 100kw is somewhere around 140 horsepower. It may not be enough to escape earth's gravity (if not, maybe the mars or the moon?), but I wouldn't discount the possibility immediately without more information (like what do these thrusters weigh, and how much propellant do they need to carry).
The hardest part would be providing a 100kw power source, but this is the same problem as supplying power to the space elevator climbers, and it might be solvable with wireless power transmission (big lasers and solar panels).
it would be extremely easy for them to see this news (here or else where) and start shooting them the second they see them comming..
For law enforcement, that is a far better scenario than the alternative, which is to send an actual person in to see what's going on, and have him/her get shot at.
The researchers studied about 300 children with an average age of 10. The children, all Caucasian, came from six counties in the Cleveland area. As a group, males -- but not females -- who had the variant gene had IQ scores about 20 points lower than males who didn't.
It would be interesting to know if the same findings hold true in older populations; it may be that the gene only affects the rate at which the brain develops, not its eventual capabilities.
Slashdot Mirror
This actually is somewhat important for establishing historical data for carbon dioxide density in the atmosphere. Presumably, the new data will allow someone to extend this graph, and see where we are now relative to a million years ago.
Perhaps the solution would be to require companies to put down a deposit whenever they stick something in orbit. They get it back when the object leaves orbit.
I suppose that depends on the intended purpose. I don't think assembling a space station out of it is practical (at least, not without a lot of manufacturing infrastructure that we don't have in orbit right now), however, it could be used as part of a space elevator counterweight (assuming the significant orbit modification can be made more cheaply than launching a similarly heavy object from the ground), or use the debris as the reaction mass for a mass driver, or use it as a radiation shield.
Maybe if we gathered them in one place we could eventually have a new (very small) moon that could be easily tracked and avoided. I suppose it would be below the roche limit, and would thus perhaps need to be caught in a net, or a strong magnet.
Anyone care to guess which would require more delta v, deorbiting a satelite or moving it to a "designated rubbish pile"? It seems like some space debris would be salvageable, it seems a shame to drop it back into the atmosphere after spending so much fuel to get it up there in the first place.
Anyone have any good ideas for the names of aforementioned moons?
I agree with the parent but would like to add that the best way to learn chess is to play against those with a similar level of skill. That way, no one is bored with an easy win or demoralized by inevitable defeat, and everyone gets better at roughly the same rate.
The argument isn't that select and poll don't work with large numbers of sockets, the problem is that they aren't scalable. Both system calls take, as an argument, a list of file descriptors the program is interested in listening to. If there are hundreds (or thousands) of sockets open, those lists can become unweildy. The scalable alternatives remember which file descriptor the process has asked to be notified about previously, rather than require that the process sends the kernel a complete list every time.
I don't doubt that that's probably true in some cases. Few client programs have very many sockets open at once, so select or poll would be a good choice.Yeah, we have that in America for major appliances (I'm not sure if it's mandatory or not). I think it should be mandatory for small devices as well. I'm often surprised by how much heat a wireless router can generate (though, this time of year I don't mind so much as it keeps my apartment warm).
...the one described in this earlier slashdot story? If so, it looks like they've progressed from concept to prototype.
I suppose the hard part of what you propose is separating the CO2 from the exhaust. I don't know if this is the best method, but one way is to compress the air until the CO2 liquifies. Unfortunately, this would require a lot of energy, probably more than the power plant produces by burning coal in the first place. By comparison, using algae to absorb the carbon dioxide sounds pretty good.
Of course, as the article says, there aren't any rules restricting congress from using cookies, only the executive branch is restricted in this way, so the earlier story about the NSA using cookies was much more relevant in that respect.
The RSA patents have expired, and the algorithms are well understood. There's really no reason to stick with RSA's implementation.
Fortunately for us, key escrow didn't have enough political support, and we now have crypto anarchy. (That's a very good book, by the way.) Despite what naysayers may say, we still live in a democracy, and NSA doesn't make all the decisions.
No one except the NSA really knows if the NSA has some magic box that can factor large primes, but a lot of people have worked on the problem without breaking RSA with some progress made, but no real success (assuming approprately large keys). I'd personally be more worried about the NSA (or others) tracking the source and destination of email messages, which is much more difficult to hide than the message contents -- and encryption is probably the best way of getting picked out of a crowd for additional scrutiny (which isn't to say that encryption is a bad idea, just that someone with something to hide ought to make sure their secrets aren't discoverable through some other unencrypted channel that would have been ignored if he/she haden't drawn attention to him/herself).
This is already being done by many HAMs. It's called IRLP.
I think you're comparing the 815 pound weight of Smart-1 (which is the weight of the whole probe including thrusters, fuel, batteries, scientific equipment, etc...) to the 7,774 pound weight of SSME, without fuel.
Also, the SSME is built to lift a very heavy space shuttle (and worse, its 4 million pounds of fuel) to orbit. Of course it needs a lot of power. Presumably, this new thruster does not need to carry as much propellant because it expells it at a higher velocity. If this thruster is light enough that it can lift its own weight, plus that of its propellant and energy source, then it can carry objects to orbit. It doesn't need 12 million horsepower if it doesn't weigh 4.5 million pounds.
You're probably right that it isn't strong enough, but I don't think your comparison is sound. I also agree that this would be a wonderful way to cruise around the solar system. (It might even be a good way to push heavy things like meteoroids around).
I would hesitate to call this a "very low thrust" engine, since 100kw is somewhere around 140 horsepower. It may not be enough to escape earth's gravity (if not, maybe the mars or the moon?), but I wouldn't discount the possibility immediately without more information (like what do these thrusters weigh, and how much propellant do they need to carry).
The hardest part would be providing a 100kw power source, but this is the same problem as supplying power to the space elevator climbers, and it might be solvable with wireless power transmission (big lasers and solar panels).