My question exactly. Or almost exactly -- from the number of zeroes you're using the European "billion" (million million) rather than the North American (thousand million).
But even assuming the latter, a 1 km square sail gives roughly 6 times the energy Earth uses currently (by their figures). And a 1 km square sail is a heck of a lot easier to build than an 8000 km square one.
That number, though, surprises me. Sunlight flux is less than 1.5 kW/square meter at Earth's distance. Call it 2 GW per square kilometer -- nowhere near Earth's energy use (in the 10-20 TW range)*. This is talking about tapping solar wind rather than sunlight, but I find it hard to believe that solar wind flux is that many orders of magnitude more energy intensive than sunlight. If it is -- and despite Earth's magnetic field -- global temperatures are going to be driven mostly by solar wind effects. The numbers in TFA must be wrong, i.e. typical popular science reportage.
(* TFA says an 8,400 km square sail will produce "a billion billion gigawatts", which works out to over 14 terawatts per square kilometer. The numbers are totally fucked up. Somewhere in there I think somebody confused meters with kilometers and/or watts with kilowatts.)
The first two men on the moon are world famous, but very few people can name who the third or fourth are, or indeed any of the others.
I know plenty of people who can -- but I'll admit it's still probably a small and select fraction of the population. I've had long conversations (on different occasions) with Pete Conrad and Alan Bean, the third and fourth. To me their feat -- landing near Surveyor III, and bringing back pieces of it -- was more impressive than Armstrong and Aldrin's. Apollo 11 would have been a success if they'd landed anywhere on the Moon. Apollo 12 demonstrated an ability to do pinpoint landings at a particular location, an essential capability for building and operating a moon base (a capability never exploited, alas, but that's what got me excited at the time) and for doing targeted scientific exploration (which was done, some).
Interestingly, while Conrad was justifiably pleased with the landing, he was more proud of his rescue of Skylab -- which involved just heaving the stuck solar panel loose manually when the tool NASA improvised didn't work -- since that saved the whole Skylab program. But probably even fewer people know about that than know he walked on the Moon.
If struck right, you'll actually knock bits of steel off - these have a lot of kinetic energy since you were moving the (much bigger) objects pretty quickly. The blob of steel will glow red hot and light stuff on fire.
There's a little bit more to it than that: tiny bits of iron (thus with a high surface area to volume ratio) will spontaneously combust in air, so they're actually burning, not just glowing. The kinetic heat helps that happen with somewhat larger bits. That's why it works with iron or steel but not other metals to which the same energy transfer argument would otherwise apply (like bronze).
Yep. I had a PSU failure take out the onboard electronics for two hard drives (one IDE, one SCSI - this was a while back), two CPUs, a graphics card, and a few other odds and ends. The surprising thing was that anything at all worked after that (SCSI controller and NIC were OK -- although I didn't trust them after that).
The drive circuitry failed spectacularly, blowing ICs off the cards and vaporizing circuit traces. The sound and smoke was my first clue that something was seriously wrong. I made sure I got a high-end, high-power PSU for the replacement box.
It's gotta be 200 miles -- which is about the distance you can go on a tank of gas in most cars -- or you can forget about road trips.
Geez, just tow a small trailer with a generator. Sure, it's using gas, but not much.
In fact if the car chassis will take the weight, it doesn't even need to be a trailer, just mount the thing directly on a towbar fitting like some bike racks. Shouldn't be that heavy.
Yes, depending on what your definition of "hiking distance" is. Consider Peru, where you can go from desert across the Andes to the Amazon basin in a couple hundred miles -- a week or two hike for someone in good shape. Plenty of other places too.
Jews and Muslims each have their own calendar, both quite different and with different starting years from the Christian (okay, now called "Common Era") calendar which this date allegedly is based on.
That TGV record is for a test train on a specially prepared track with customized power feed and tensioning on the catenary. It's not clear from TFA, but I believe the Chinese are claiming the record for a production train on production track (ie equivalent to scheduled runs).
See e.g. this from the Wikipedia TGV article: "A TGV service previously held the record for the fastest scheduled rail journey with a start to stop average speed of 279.4 km/h (173.6 mph),[2][3] which was surpassed by the Chinese CRH service Harmony express on the Wuhan-Guangzhou High-Speed Railway in 2009."
Habzone boundary computations are fuzzy when one takes things like clouds and stellar variability into account. Selsis et al calculate an inner boundary (for present-day Sol) at between 0.7 and 0.9 AU (Venus is at ~0.72 AU), and an outer boundary between 1.7 and 2.4 AU (Mars is at 1.4-1.7 AU). W. von Bloh et al define the habzone in terms of the range in which Earth-like photosynthesis can take place, which is narrower.
Article here, better image here. (The Gl581 diagrams do not show the recently announced f and g planets.)
We know of technologies which would let us launch a probe to a meaningful fraction of lightspeed (say 0.1c). These include pulsed nuclear detonations, and launching lasers and masers (eg Starwisp). Right now we don't have the will to spend the kind of money it would take to actually build and launch something like that, but the problem has been studied by some of the best minds in the (high energy) physics business, to the point of proof-of-concept experiments. (I.e. I'm not talking about still-hypotheticals like the Bussard ramjet.)
Sure, at 0.1c that's still a 200 year trip to Gliese 581. On the other hand, if we'd launched something like that to Alpha Centauri back in the Apollo era (we couldn't have, but if) it would be reaching there just about now.
The habzone is defined as the range at which planetary temperatures could be in the right range for liquid water. Whether temperatures are in that range on a given planet depends on other factors, such as atmospheric density, greenhouse effect, etc. At stellar distances all we can tell (and even that, not easily) is the former -- although we're getting closer to being able to read atmospheric composition under some circumstances.
Swap the orbits of Mars and Venus and they might be darn near habitable. (Mars perhaps not due to atmosphere loss. Venus perhaps not due to a too-thick even if not too-hot atmosphere, unless a lot of it froze out as polar caps.)
Venus and Mars are also rocky "Earthlike" planets orbiting roughly in the habzone ("goldilocks" zone).
I'd like to see truly terrestrial planets as much as (more than, probably) the next guy, but I think the reportage here is a bit hyped. Especially given a ~3x mass, that gives it roughly 1.44x the surface gravity (and higher likelihood of a Venus-like atmosphere).
No readily available source. It was related to me by a psychologist who specializes in gifted kids, and a quick google turns up a lot of sites that say a heightened sense of fairness is one indicator of same.
That personality type sounds more like the dime-a-dozen IQ 120 types (enough to be smarter than most other people but not smart enough to really be secure about it, so they bury their insecurity under assholery), but yeah, if fits some of the Mensa crowd too. (And lets face it, the very nature of an organization like Mensa tends to select people like that. A lot of my friends are ex-Mensa: joined, realized what jerks many of the other members were, and quit.)
But an asshole can still have a sense of fairness; they're just obnoxious about it.
I don't recall exactly. It came up in a discussion with a psychologist/psychiatrist about testing of high IQ kids (in the territory where most modern tests don't measure very accurately). Google turns up a lot of links citing "sense of fairness" as one sign of an intellectually gifted child, but I don't have the time right now to track down the original research.
so the worm could be easily retooled to strike back at the creator. The idea that a nation would be incompetent enough to allow such a weapon as this to be redirected back at their critical infrastructure doesn't sit well with me.
Actually that sort of incompetence strikes me as more the sort of thing a state-sponsored effort might miss as compared to a the efforts of a small group used to thinking in terms of vulnerabilities. I.e. it suggests that the group who found the exploits is different from the group who implemented the hack, which suggests a more distributed effort.
Or it could just be a small group who don't give a rat's ass about anybody's infrastructure, including their own.
You just need to get the hollywood fabricated ideas about teams of small teams of omnipotent superhacker "gods" out of your mind, because they don't exist.
Not quite in the Hollywood image they don't, no. But assuming that such hacking is beyond the efforts of one or two highly intelligent, knowledgeable and motivated individuals is a big mistake. You just need someone with an IQ in the 150 range who reads manuals and code for fun and thinks so far outside the box he can barely see it from there.
(Some 35 years ago I routinely pwned the campus mainframe, a Burroughs B6700, through a combination of inspired guesswork (giving me access to allocated but unused accounts), dumpster diving (hey, a listing of the OS, that looks interesting. Gee, what's this string "&:*" being passed to a call that expects the [root-equivalent] password?), social engineering (me at a Burroughs sales office: "I'm a student at X, can I get some B6700 manuals?" They: "We don't have any for sale here, but [checks in back] here are some old ones I'll just give you." Systems programmer back at X: "How'd you get those? We can't even get those!") and plain outside the box thinking (Sys programmer: "but you can't edit a Burroughs backup tape!" Me: "not on the Burroughs, no. But on the IBM 360/50..." He: "Oh, shit." Being able to edit a Burroughs backup tape let you (or me) get around the fact that only a program tagged as a compiler could tag a binary file as executable, and only an operator console command could tag a program as a compiler. But if you could create your own arbitrary executable binaries, you had access to all kinds of system calls normally reserved to the OS.) Of course those were more naive, innocent times, pre Morris worm, and terms like "dumpster diving" and "social engineering" hadn't been coined yet. It's a little harder these days (back then I was barely even trying), but there are better tools available, so don't fool yourself. Script kiddies are one thing -- it's the folks inventing those scripts, or rather, the ones who invent scripts the kiddies never see, that you need to worry about.)
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My question exactly. Or almost exactly -- from the number of zeroes you're using the European "billion" (million million) rather than the North American (thousand million).
But even assuming the latter, a 1 km square sail gives roughly 6 times the energy Earth uses currently (by their figures). And a 1 km square sail is a heck of a lot easier to build than an 8000 km square one.
That number, though, surprises me. Sunlight flux is less than 1.5 kW/square meter at Earth's distance. Call it 2 GW per square kilometer -- nowhere near Earth's energy use (in the 10-20 TW range)*. This is talking about tapping solar wind rather than sunlight, but I find it hard to believe that solar wind flux is that many orders of magnitude more energy intensive than sunlight. If it is -- and despite Earth's magnetic field -- global temperatures are going to be driven mostly by solar wind effects. The numbers in TFA must be wrong, i.e. typical popular science reportage.
(* TFA says an 8,400 km square sail will produce "a billion billion gigawatts", which works out to over 14 terawatts per square kilometer. The numbers are totally fucked up. Somewhere in there I think somebody confused meters with kilometers and/or watts with kilowatts.)
how do you successfully attack someone who controls a 30 million billion jiggiewatt deathray?
Get some farm kid to fire a torpedo down a vent shaft from his X-wing?
The first two men on the moon are world famous, but very few people can name who the third or fourth are, or indeed any of the others.
I know plenty of people who can -- but I'll admit it's still probably a small and select fraction of the population. I've had long conversations (on different occasions) with Pete Conrad and Alan Bean, the third and fourth. To me their feat -- landing near Surveyor III, and bringing back pieces of it -- was more impressive than Armstrong and Aldrin's. Apollo 11 would have been a success if they'd landed anywhere on the Moon. Apollo 12 demonstrated an ability to do pinpoint landings at a particular location, an essential capability for building and operating a moon base (a capability never exploited, alas, but that's what got me excited at the time) and for doing targeted scientific exploration (which was done, some).
Interestingly, while Conrad was justifiably pleased with the landing, he was more proud of his rescue of Skylab -- which involved just heaving the stuck solar panel loose manually when the tool NASA improvised didn't work -- since that saved the whole Skylab program. But probably even fewer people know about that than know he walked on the Moon.
It's Alan Bean, not Gordon. Apollo 15 was Scott and Irwin, Worden was the Command Module pilot.
But well done. I had to look up Apollo 15 to be sure.
Ssh! That's supposed to be a secret!
If struck right, you'll actually knock bits of steel off - these have a lot of kinetic energy since you were moving the (much bigger) objects pretty quickly. The blob of steel will glow red hot and light stuff on fire.
There's a little bit more to it than that: tiny bits of iron (thus with a high surface area to volume ratio) will spontaneously combust in air, so they're actually burning, not just glowing. The kinetic heat helps that happen with somewhat larger bits. That's why it works with iron or steel but not other metals to which the same energy transfer argument would otherwise apply (like bronze).
Yep. I had a PSU failure take out the onboard electronics for two hard drives (one IDE, one SCSI - this was a while back), two CPUs, a graphics card, and a few other odds and ends. The surprising thing was that anything at all worked after that (SCSI controller and NIC were OK -- although I didn't trust them after that).
The drive circuitry failed spectacularly, blowing ICs off the cards and vaporizing circuit traces. The sound and smoke was my first clue that something was seriously wrong. I made sure I got a high-end, high-power PSU for the replacement box.
It's gotta be 200 miles -- which is about the distance you can go on a tank of gas in most cars -- or you can forget about road trips.
Geez, just tow a small trailer with a generator. Sure, it's using gas, but not much.
In fact if the car chassis will take the weight, it doesn't even need to be a trailer, just mount the thing directly on a towbar fitting like some bike racks. Shouldn't be that heavy.
Yes, depending on what your definition of "hiking distance" is. Consider Peru, where you can go from desert across the Andes to the Amazon basin in a couple hundred miles -- a week or two hike for someone in good shape. Plenty of other places too.
Jews and Muslims each have their own calendar, both quite different and with different starting years from the Christian (okay, now called "Common Era") calendar which this date allegedly is based on.
So WTF?
That TGV record is for a test train on a specially prepared track with customized power feed and tensioning on the catenary. It's not clear from TFA, but I believe the Chinese are claiming the record for a production train on production track (ie equivalent to scheduled runs).
See e.g. this from the Wikipedia TGV article: "A TGV service previously held the record for the fastest scheduled rail journey with a start to stop average speed of 279.4 km/h (173.6 mph),[2][3] which was surpassed by the Chinese CRH service Harmony express on the Wuhan-Guangzhou High-Speed Railway in 2009."
Habzone boundary computations are fuzzy when one takes things like clouds and stellar variability into account. Selsis et al calculate an inner boundary (for present-day Sol) at between 0.7 and 0.9 AU (Venus is at ~0.72 AU), and an outer boundary between 1.7 and 2.4 AU (Mars is at 1.4-1.7 AU). W. von Bloh et al define the habzone in terms of the range in which Earth-like photosynthesis can take place, which is narrower.
Article here, better image here. (The Gl581 diagrams do not show the recently announced f and g planets.)
We know of technologies which would let us launch a probe to a meaningful fraction of lightspeed (say 0.1c). These include pulsed nuclear detonations, and launching lasers and masers (eg Starwisp). Right now we don't have the will to spend the kind of money it would take to actually build and launch something like that, but the problem has been studied by some of the best minds in the (high energy) physics business, to the point of proof-of-concept experiments. (I.e. I'm not talking about still-hypotheticals like the Bussard ramjet.)
Sure, at 0.1c that's still a 200 year trip to Gliese 581. On the other hand, if we'd launched something like that to Alpha Centauri back in the Apollo era (we couldn't have, but if) it would be reaching there just about now.
The habzone is defined as the range at which planetary temperatures could be in the right range for liquid water. Whether temperatures are in that range on a given planet depends on other factors, such as atmospheric density, greenhouse effect, etc. At stellar distances all we can tell (and even that, not easily) is the former -- although we're getting closer to being able to read atmospheric composition under some circumstances.
Swap the orbits of Mars and Venus and they might be darn near habitable. (Mars perhaps not due to atmosphere loss. Venus perhaps not due to a too-thick even if not too-hot atmosphere, unless a lot of it froze out as polar caps.)
Venus and Mars are also rocky "Earthlike" planets orbiting roughly in the habzone ("goldilocks" zone).
I'd like to see truly terrestrial planets as much as (more than, probably) the next guy, but I think the reportage here is a bit hyped. Especially given a ~3x mass, that gives it roughly 1.44x the surface gravity (and higher likelihood of a Venus-like atmosphere).
Indeed. One of the civilian uses of depleted uranium is in radiation shielding.
Exactly so.
"...we've proved it again and again,
That if once you have paid him the Dane-geld
You never get rid of the Dane."
one of the funniest things I've seen on /. this month. If the Earth needs defending against aliens, I'm calling you. ;)
Heh, thanks!
(Speaking of funny and defending against aliens, you might like my story "The Gremlin Gambit", see my stories page.)
Shoot a bullet through their material...
God Bless America!. Even in science, we can solve any problem by just shooting at it.
Hey, back when I took Physics 105, a rifle was standard lab equipment. And that was in Canada.
(See 'ballistic pendulum'.)
If I ever write an autobiography about my time as Programmer On Duty way back when at Concordia University, I'm going to have to title it "I, POD".
Or not.
No readily available source. It was related to me by a psychologist who specializes in gifted kids, and a quick google turns up a lot of sites that say a heightened sense of fairness is one indicator of same.
That personality type sounds more like the dime-a-dozen IQ 120 types (enough to be smarter than most other people but not smart enough to really be secure about it, so they bury their insecurity under assholery), but yeah, if fits some of the Mensa crowd too. (And lets face it, the very nature of an organization like Mensa tends to select people like that. A lot of my friends are ex-Mensa: joined, realized what jerks many of the other members were, and quit.)
But an asshole can still have a sense of fairness; they're just obnoxious about it.
I don't recall exactly. It came up in a discussion with a psychologist/psychiatrist about testing of high IQ kids (in the territory where most modern tests don't measure very accurately). Google turns up a lot of links citing "sense of fairness" as one sign of an intellectually gifted child, but I don't have the time right now to track down the original research.
so the worm could be easily retooled to strike back at the creator. The idea that a nation would be incompetent enough to allow such a weapon as this to be redirected back at their critical infrastructure doesn't sit well with me.
Actually that sort of incompetence strikes me as more the sort of thing a state-sponsored effort might miss as compared to a the efforts of a small group used to thinking in terms of vulnerabilities. I.e. it suggests that the group who found the exploits is different from the group who implemented the hack, which suggests a more distributed effort.
Or it could just be a small group who don't give a rat's ass about anybody's infrastructure, including their own.
You just need to get the hollywood fabricated ideas about teams of small teams of omnipotent superhacker "gods" out of your mind, because they don't exist.
Not quite in the Hollywood image they don't, no. But assuming that such hacking is beyond the efforts of one or two highly intelligent, knowledgeable and motivated individuals is a big mistake. You just need someone with an IQ in the 150 range who reads manuals and code for fun and thinks so far outside the box he can barely see it from there.
(Some 35 years ago I routinely pwned the campus mainframe, a Burroughs B6700, through a combination of inspired guesswork (giving me access to allocated but unused accounts), dumpster diving (hey, a listing of the OS, that looks interesting. Gee, what's this string "&:*" being passed to a call that expects the [root-equivalent] password?), social engineering (me at a Burroughs sales office: "I'm a student at X, can I get some B6700 manuals?" They: "We don't have any for sale here, but [checks in back] here are some old ones I'll just give you." Systems programmer back at X: "How'd you get those? We can't even get those!") and plain outside the box thinking (Sys programmer: "but you can't edit a Burroughs backup tape!" Me: "not on the Burroughs, no. But on the IBM 360/50..." He: "Oh, shit." Being able to edit a Burroughs backup tape let you (or me) get around the fact that only a program tagged as a compiler could tag a binary file as executable, and only an operator console command could tag a program as a compiler. But if you could create your own arbitrary executable binaries, you had access to all kinds of system calls normally reserved to the OS.) Of course those were more naive, innocent times, pre Morris worm, and terms like "dumpster diving" and "social engineering" hadn't been coined yet. It's a little harder these days (back then I was barely even trying), but there are better tools available, so don't fool yourself. Script kiddies are one thing -- it's the folks inventing those scripts, or rather, the ones who invent scripts the kiddies never see, that you need to worry about.)