You sure are noisome for somebody who is just here to watch. Makes me glad I don't have to watch movies with you as you probably shout at the screen.
An your noise is so inaccurate! I don't recall defending Al Gore! Please don't bring your obsession with Al Gore into my troll space. If you're going into another troll's turf, please make it topical at least.
And the only science I put forth was some social-pseudoscience / conjecturing about tmosley in an attempt to match his pseudoscience and conjectural griping which, somewhat sadly, does seem intended as scientific discussion. I know all too well that I'm not going to change his mind about anything (see links in my previous post). I'm just here to heckle him.
I'd also like to reiterate the point of my previous post, which is that I'm calling you a hypocrite. You're trying to call me out for failing to address tmosley's obviously non-scientific post masquerading as scientific rigor without using scientific rigor myself and then you fail to use your own scientific rigor when calling out my intentionally non-scientific post. I do feel somewhat flattered by our little circle jerk here -- you are obviously very thorough when stalking your men as evidenced by your extensive knowledge of Al Gore -- but I want you to know that I may not be your type. My support of climate science and alternative energy is not at all motivated by compassion. Rather, it is motivated by a totally selfish desire for clean air, a lower trade deficit, and a desire to bankrupt those despicable oil cartels. I'm also more a stalker than a stalkee. If you want a submissive partner, look for the handkerchief in the right pocket. I have enjoyed our dance, but I was kind of hoping for a more cutting insult than 'angry child' or 'crazy'. That's just too simplistic for me.
See my other comment. I'm not going to pretend that I know all about it, but I believe that the Chinese law's intent is to prevent civil action after a period of 3 months.
Perhaps I fired that comment off half-cocked. I'm not going to pretend I know all about it. The short answer is "I don't know". However, I believe that in Western countries, artists may assert rights to their works in civil court. For example, if I release a song in May and you copied my song and released an exact sound-alike in August, then I could sue you for cramping my style and expect a judge or jury to settle it for us. It is legal in Western countries to record a cover of somebody else's song under compulsory license without their permission and the original songwriter and publisher will receive legally mandated royalty rates on sales of the new recording -- in that sense the two systems are the same. I do not know if there is any time limit attached. It seems to me that the intent in the Chinese law is to prevent civil action by setting a time frame after which all civil remedies are prohibited. The comments of the affected Chinese artists clearly indicate that they are unhappy about it. I personally think it sucks the wind out of the music recording business model if people are permitted to copy and "use" your music however they like after 3 months.
As for "our own RIAA-ruled vision of copyright law" as you put it, I'm not sure how I feel. Full disclosure: I have made a little money from music recording and still get royalty checks from ASCAP every now and then. I believe that if I sell someone a song that the terms of that sale should be clear to both of us and pretty flexible. Obviously, they should be able to play it anywhere they want on any device they want until hell freezes over, pass it on to their kids, etc. I want people to be able to give my song to friends or play it at parties or play it for their family. This is how songs become popular. That somebody would take my song and put it on BitTorrent so the entire world can have it for free bothers me. That some loathsome creature like Kim Dotcom can make a fortune selling advertising on the back of content that he had no hand or share in creating bothers me too. I've never sued anybody, though. I don't like the RIAA. I don't like big record companies. I welcome P2P technology and the decentralization of the music industry. I like that it's easier to make and distribute music now than it has ever been. I love that NIN and Radiohead made tons of money from voluntary contributions. I LOVE that some of these douchebag record companies have been taken down a few notches. Their arrogance and that radio pay-for-play stuff was just nauseating.
On the other hand, I often wonder about the future of music. You need enormous amounts of money to record music with the London Symphony Orchestra. Those fantastic recording studios at Abbey Road with the 90-channel Neve 4078 boards in them cost millions of dollars to build and thousands of dollars a day to rent. While you don't need the LSO or one of those Neve boards to crank out garage rock or electro clash or house music, they are kind of magic things that may soon become extinct. Dark Side of the Moon -- best selling record ever -- took something like six months or a year to record at Abbey Road and was done on the record company's dime. Aside from record companies, who is willing to pay for something like that?
I really don't want to ignite any flame wars or anything, but I do hope that people who make (good) music get compensated for it. I hope that people who enjoy music appreciate that it takes effort to create and will consider sending some compensation to the artists -- however small that compensation may be. I hope that people don't feel entitled to have all their music for free. I hope the RIAA stops acting like a bunch of dickheads. I hope I can watch Game of Thrones soon without having to get cable or subscribe to HBO or whatever -- I'm totally willing to pay for it!
The lifetime of entertainment media is surprisingly short. Most movies make at least 1/3 of their ultimate revenue in the first weekend. Perhaps the way to define "orphan works" is to expire copyright when 95% of the ultimate revenue has been extracted. The movie industry already makes that calculation to decide when to end theatrical release.
Where did you get this "fact"? This may be true of an initial box office run, but fails entirely to account for DVD sales, streaming, download, etc. And what about stuff that rears its ugly head over and over again like Star Wars?
And what if you don't want to license your music to someone -- e.g., I don't want to license my band's music to Rick Santorum's campaign because I think he's a cocksucker? Or suppose Radiohead doesn't want their song used in a MacDonald's commercial? And what about derivative works? E.g., I take your dance song, remix it a little and make *my* dance song which totally cannibalizes your revenue stream a mere 3 months after it launches?
It seems pretty clear to me that this defines a vision of copyright law that is distinctly communist in nature and represents a business model where artists have no rights to their own creations.
If you are looking for scientific rigor, perhaps you should check your own posts. I can't seem to find anything remotely informative there, Mr. Peanut Gallery.
I'd wager you would fall into one of those believe-anything groups, tmosley. Every comment you make bets on a world of endless oil and no climate change. Let me make some verifiable predictions about you based on your commentary:
1) You drive a big, gass-guzzling pickup or SUV 2) You live in a predominantly rural state like Texas or Montana -- definitely not East Coast or West Coast 3) You believe Obama is a socalist and suspect he's secretly a muslim 4) You generally vote Republican or for whoever's right of them (e.g., David Duke) 5) You ardently believe that predictions of climate change are just a fraudulent racket so people like Al Gore can make money
Do you ever given any though to the geopolitical ramifications of oil addiction? Or the fact that the Chinese demand for oil has grown so much that PetroChina now produces more oil than Exxon? Just so you know, if those tree-hugging, pinko liberals do manage to get their electric cars and alternative energy sources working, it means that the price of oil and electricity will be that much lower for you because they won't be buying any. However, you will still be funneling money straight to terrorists and camel jockeys in saudi arabia. As a liberal, I applaud your generosity for helping those poor arabs. Without your petro dollars, their nations would collapse and then they would likely mobilize for war against us infidels. Lord knows we can't have that. Fighting a Billion muslims is way more expensive than fighting 20 million here and 20 million there. It's cheaper just to pay them off.
Oh c'mon silly! Everyone knows he just did that because he didn't have a heart. Now they got him one! Everything is going to be fine now -- or at least for the next five years til they have to murder another young athlete to get him a new heart.
The existance of civilian technologies based on military ones does not factor in.
Go ahead and pick your arbitrary philosophical cutoff point and keep living your blind existence. What you fail to realize is that technology almost always flows the other way. People who are fat and happy and peaceful have little motivation to create ground-breaking technologies. You're like someone who eats meat and, denying that meat comes from animals, calls oneself a vegetarian.
Your analysis is hardly better. What he has really done is to abandon Maker Faire -- a neat thing and definitely not dedicated to destruction of life -- which accepted money from DARPA whose sole purpose is also actually not the destruction of life -- unless you think perhaps they plan to travel space to kill life forms elsewhere. And actually, he is still supporting DARPA because his tax dollars go there.
His outrage, however nobly intended, does nothing to hurt DARPA at all and instead is a blow to Maker Faire, which is sad.
It's true that the Altman deserves props for sticking to his principles. And technically speaking, I did not say that 'DARPA is not so bad'. What I did mean to do is point out that Altman and you and I all benefit from the fruits of defense research and must own and live with this fact -- or boycott the Internet (and all those other goodies) too. Why stop at the maker faire? Why not boycott everything that has come from war spending? As long as we are stick to principles, we might as well go whole-hog!
I'm only taking a piss here. I know that nobody lives their life completely ethically or without compromise. One has to start somewhere I guess. Personally, I don't think DARPA is where to start. To me, this seems a bit like Altman throwing the baby out with the bath water.
People just don't realize that the path of technology is almost ALWAYS military -> business -> consumer. Wars have resulted in tremendous advances in techology. The bigger the war, the greater the advances. Some examples of military technology now used for consumer applications: * computers * computer networking * cellular phone technology * jet airplanes (even prop planes too - the Wright brothers worked for the military in WWI) * rockets, space travel (perhaps not consumer-level yet but SOON) * nuclear technology
Nothing -- and I mean NOTHING -- quite gets the mind racing to invent like contemplation of one's one mortality or enslavement.
I support the guy's right to boycott anything he likes over principles and sort of admire it too, but I kind of hold it against him at the same time.
12% C is 3.598 x 10^7 meters per second. To accelerate to that speed would require a very long time. Assuming you could accelerate at 10m/s^2 (1 G) it would take you 3.6 x 10^6 seconds which is about a month and a half. Obviously a chemical rocket can't burn for a month and a half. My understanding of the physics is pretty limited but I believe that a fission-fragment rocket is highly efficient (in terms of how much thrust you get per unit mass) with theoretical specific impulses possible between 100,000 and 1,000,000 but I don't think they provide enough thrust to accelerate an object weighing rougly a metric ton (or more if humans are involved) at 1G for a month and a half. The wikipedia article on specific impulse hints that such highly efficient engines tend to be limited in the amount of thrust they provide:
A variety of other non-rocket propulsion methods, such as ion thrusters, give much higher specific impulse but with much lower thrust; for example the Hall effect thruster on the SMART-1 satellite has a specific impulse of 1,640 s (16,100 m/s) but a maximum thrust of only 68 millinewtons. The hypothetical Variable specific impulse magnetoplasma rocket (VASIMR) propulsion would theoretically yield a minimum of 10,000300,000 m/s but would probably require a great deal of heavy machinery to confine even relatively diffuse plasmas, and so would be unusable for high-thrust applications such as launch from planetary surfaces.
The basic idea -- as I understand it -- is that these types of engines make very efficient use of their propellant's mass (lots of thrust per kg of propellant) but that they cannot create a lot of thrust at one time. They push weakly, but for extended periods of time at high efficiency.
I used to know how to do this kind of physics but now I can't. The exhaust velocity of fission-fragment engines is estimated at 3-5% C. If the plan is to reach 12% C, I think you need minimally 4 kg of propellant per kg of payload -- and in reality much more because the fuel you burn at first has to push not just the payload but the fuel to be used later as well.
How much fissionable material are you imagining we'll have for this fission fragment motor? Will not that enormous mass of fissionable material (enough to push for half the distance to A.C. and then decelerate the craft for the second half) not be itself an enormous encumbrance on your acceleration graphs, thus BADLY affecting your calculations? It's been a long time since I've done any related math, but I believe it takes an ENORMOUS amount of propellant to push something for 23 years. If I recall correctly, pushing the fuel itself is the essence of the problem. And forget about solar sails. Once you reach the (relatively close) heliopause, you can no longer rely on the sun for a push. There's basically no wind to sail on in deep space.
And, again, please don't get me wrong. I want interstellar travel to happen very badly. I have a serious love for romantic notions and sci fi. It's going to take a profound revolution in propulsion technology to change anything.
Our best bet is probably a TINY probe that somehow has enormous transmission capabilities. I'd start with something solar powered that can harness the energy of Alpha Centauri for transmission and work back from that.
PS: If you end up doing any math, please share. Would love to see it. My calculus muscles are badly atrophied.
The heliopause, which has not yet been reached by Voyager 1 is apparently 23 x 10^9 km from earth. Alpha Centauri, the nearest star to our sun is 4.366 light years away which is 4.1306 x 10^13 km away.
If it has taken 38 years for Voyager 1 to reach the Heliopause, it would take 1,795.9 times as long to reach Alpha Centauri at that speed which comes out to something like 68,000 years. I'm assuming a couple of things of course: * the speed so far is roughly the speed it will continue to travel * it can escape the sun's gravitational well.
Suppose we are somehow miraculously able to accomplish the following: * we send a system powerful enough to transmit an intelligible signal to us across 4.5 light years of space * we somehow manage to travel 100 times faster than Voyager 1
You're still talking about roughly 680 years for it to get there. There might be some tiny relativistic effects that come into play, but I doubt they would alter the situation much. Are you sending humans? If so, you have to dramatically increase the weight of the vehicle to accommodate life-sustaining water/air/energy in which case you also need shit loads of propellant if you want to slow down on the other end. Forget entirely about the difficulty of insuring the survival of roughly 20 generations of humans against the problems of cosmic radiation and health and reproductive problems related to roughly a millenium spent weightless and getting fried by space rays.
You keep using that word. I do not think it means what you think it means. ~ Inigo Montoya
Are you out of your mind? Voyager 1, launched in 1977 hasn't even reached the heliopause and it doesn't need to contain any food, water, oxygen, or energy to support a single person. Don't get me wrong, I'm hoping for a breakthrough of some kind. The problem is *not* tractable.
mod parent up. When you speak sense to certain folks, they hear crazy talk. And, conversely, crazy talk (e.g., anything said by pRick Santorum) makes sense to them.
My girlfriend keeps receiving spam mail from the Yahoo account of one of her deceased friends. Apparently the account has been compromised. Such a bummer.
There were so many things backward about this I thought it was opposite day, not valentine's day: a Republican from Texas arguing for more spending by the federal government instead of privatization -- for science! WTF?
How does building another refinery result in a step toward energy independence? And how, exactly is this post 'insightful' ?
More importantly, are you sure this is the right thing to do? At $12 per watt ($14 billion, 2.2GW). That's several times more than the installed cost of solar, according to Lawrence Berkeley National Laboratory. And that doesn't include the cost of running the plant, disposing of radioactive waste that is a hazard for billions of years. Even if storage for this waste is dirt cheap, it would certainly add up over 4.5 x 10^9 years.
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Wow, what a waste of human existence you are.
Happy Easter to you too, tmosley! Let's try and stick to verifiable assertions, shall we?
Speaking of which, I made five. Any chance we could get you to verify or refute them? I like to keep my facism and ad hominem well-tuned.
You sure are noisome for somebody who is just here to watch. Makes me glad I don't have to watch movies with you as you probably shout at the screen.
An your noise is so inaccurate! I don't recall defending Al Gore! Please don't bring your obsession with Al Gore into my troll space. If you're going into another troll's turf, please make it topical at least.
And the only science I put forth was some social-pseudoscience / conjecturing about tmosley in an attempt to match his pseudoscience and conjectural griping which, somewhat sadly, does seem intended as scientific discussion. I know all too well that I'm not going to change his mind about anything (see links in my previous post). I'm just here to heckle him.
I'd also like to reiterate the point of my previous post, which is that I'm calling you a hypocrite. You're trying to call me out for failing to address tmosley's obviously non-scientific post masquerading as scientific rigor without using scientific rigor myself and then you fail to use your own scientific rigor when calling out my intentionally non-scientific post. I do feel somewhat flattered by our little circle jerk here -- you are obviously very thorough when stalking your men as evidenced by your extensive knowledge of Al Gore -- but I want you to know that I may not be your type. My support of climate science and alternative energy is not at all motivated by compassion. Rather, it is motivated by a totally selfish desire for clean air, a lower trade deficit, and a desire to bankrupt those despicable oil cartels. I'm also more a stalker than a stalkee. If you want a submissive partner, look for the handkerchief in the right pocket. I have enjoyed our dance, but I was kind of hoping for a more cutting insult than 'angry child' or 'crazy'. That's just too simplistic for me.
See my other comment. I'm not going to pretend that I know all about it, but I believe that the Chinese law's intent is to prevent civil action after a period of 3 months.
Perhaps I fired that comment off half-cocked. I'm not going to pretend I know all about it. The short answer is "I don't know". However, I believe that in Western countries, artists may assert rights to their works in civil court. For example, if I release a song in May and you copied my song and released an exact sound-alike in August, then I could sue you for cramping my style and expect a judge or jury to settle it for us. It is legal in Western countries to record a cover of somebody else's song under compulsory license without their permission and the original songwriter and publisher will receive legally mandated royalty rates on sales of the new recording -- in that sense the two systems are the same. I do not know if there is any time limit attached. It seems to me that the intent in the Chinese law is to prevent civil action by setting a time frame after which all civil remedies are prohibited. The comments of the affected Chinese artists clearly indicate that they are unhappy about it. I personally think it sucks the wind out of the music recording business model if people are permitted to copy and "use" your music however they like after 3 months.
As for "our own RIAA-ruled vision of copyright law" as you put it, I'm not sure how I feel. Full disclosure: I have made a little money from music recording and still get royalty checks from ASCAP every now and then. I believe that if I sell someone a song that the terms of that sale should be clear to both of us and pretty flexible. Obviously, they should be able to play it anywhere they want on any device they want until hell freezes over, pass it on to their kids, etc. I want people to be able to give my song to friends or play it at parties or play it for their family. This is how songs become popular. That somebody would take my song and put it on BitTorrent so the entire world can have it for free bothers me. That some loathsome creature like Kim Dotcom can make a fortune selling advertising on the back of content that he had no hand or share in creating bothers me too. I've never sued anybody, though. I don't like the RIAA. I don't like big record companies. I welcome P2P technology and the decentralization of the music industry. I like that it's easier to make and distribute music now than it has ever been. I love that NIN and Radiohead made tons of money from voluntary contributions. I LOVE that some of these douchebag record companies have been taken down a few notches. Their arrogance and that radio pay-for-play stuff was just nauseating.
On the other hand, I often wonder about the future of music. You need enormous amounts of money to record music with the London Symphony Orchestra. Those fantastic recording studios at Abbey Road with the 90-channel Neve 4078 boards in them cost millions of dollars to build and thousands of dollars a day to rent. While you don't need the LSO or one of those Neve boards to crank out garage rock or electro clash or house music, they are kind of magic things that may soon become extinct. Dark Side of the Moon -- best selling record ever -- took something like six months or a year to record at Abbey Road and was done on the record company's dime. Aside from record companies, who is willing to pay for something like that?
I really don't want to ignite any flame wars or anything, but I do hope that people who make (good) music get compensated for it. I hope that people who enjoy music appreciate that it takes effort to create and will consider sending some compensation to the artists -- however small that compensation may be. I hope that people don't feel entitled to have all their music for free. I hope the RIAA stops acting like a bunch of dickheads. I hope I can watch Game of Thrones soon without having to get cable or subscribe to HBO or whatever -- I'm totally willing to pay for it!
The lifetime of entertainment media is surprisingly short. Most movies make at least 1/3 of their ultimate revenue in the first weekend. Perhaps the way to define "orphan works" is to expire copyright when 95% of the ultimate revenue has been extracted. The movie industry already makes that calculation to decide when to end theatrical release.
Where did you get this "fact"? This may be true of an initial box office run, but fails entirely to account for DVD sales, streaming, download, etc. And what about stuff that rears its ugly head over and over again like Star Wars?
And what if you don't want to license your music to someone -- e.g., I don't want to license my band's music to Rick Santorum's campaign because I think he's a cocksucker? Or suppose Radiohead doesn't want their song used in a MacDonald's commercial? And what about derivative works? E.g., I take your dance song, remix it a little and make *my* dance song which totally cannibalizes your revenue stream a mere 3 months after it launches?
It seems pretty clear to me that this defines a vision of copyright law that is distinctly communist in nature and represents a business model where artists have no rights to their own creations.
I appreciate your awe, however disingenuous it may be. My methodologies may be controversial here, but they are based on some interesting notions:
* conservatives don't trust science any more.
* belief trumps facts
If you are looking for scientific rigor, perhaps you should check your own posts. I can't seem to find anything remotely informative there, Mr. Peanut Gallery.
I'd wager you would fall into one of those believe-anything groups, tmosley. Every comment you make bets on a world of endless oil and no climate change. Let me make some verifiable predictions about you based on your commentary:
1) You drive a big, gass-guzzling pickup or SUV
2) You live in a predominantly rural state like Texas or Montana -- definitely not East Coast or West Coast
3) You believe Obama is a socalist and suspect he's secretly a muslim
4) You generally vote Republican or for whoever's right of them (e.g., David Duke)
5) You ardently believe that predictions of climate change are just a fraudulent racket so people like Al Gore can make money
Do you ever given any though to the geopolitical ramifications of oil addiction? Or the fact that the Chinese demand for oil has grown so much that PetroChina now produces more oil than Exxon? Just so you know, if those tree-hugging, pinko liberals do manage to get their electric cars and alternative energy sources working, it means that the price of oil and electricity will be that much lower for you because they won't be buying any. However, you will still be funneling money straight to terrorists and camel jockeys in saudi arabia. As a liberal, I applaud your generosity for helping those poor arabs. Without your petro dollars, their nations would collapse and then they would likely mobilize for war against us infidels. Lord knows we can't have that. Fighting a Billion muslims is way more expensive than fighting 20 million here and 20 million there. It's cheaper just to pay them off.
Oh c'mon silly! Everyone knows he just did that because he didn't have a heart. Now they got him one! Everything is going to be fine now -- or at least for the next five years til they have to murder another young athlete to get him a new heart.
The existance of civilian technologies based on military ones does not factor in.
Go ahead and pick your arbitrary philosophical cutoff point and keep living your blind existence. What you fail to realize is that technology almost always flows the other way. People who are fat and happy and peaceful have little motivation to create ground-breaking technologies. You're like someone who eats meat and, denying that meat comes from animals, calls oneself a vegetarian.
Your analysis is hardly better. What he has really done is to abandon Maker Faire -- a neat thing and definitely not dedicated to destruction of life -- which accepted money from DARPA whose sole purpose is also actually not the destruction of life -- unless you think perhaps they plan to travel space to kill life forms elsewhere. And actually, he is still supporting DARPA because his tax dollars go there.
His outrage, however nobly intended, does nothing to hurt DARPA at all and instead is a blow to Maker Faire, which is sad.
It's true that the Altman deserves props for sticking to his principles. And technically speaking, I did not say that 'DARPA is not so bad'. What I did mean to do is point out that Altman and you and I all benefit from the fruits of defense research and must own and live with this fact -- or boycott the Internet (and all those other goodies) too. Why stop at the maker faire? Why not boycott everything that has come from war spending? As long as we are stick to principles, we might as well go whole-hog!
I'm only taking a piss here. I know that nobody lives their life completely ethically or without compromise. One has to start somewhere I guess. Personally, I don't think DARPA is where to start. To me, this seems a bit like Altman throwing the baby out with the bath water.
Recommended reading: The Ones Who Walk Away from Omelas.
Totally. I hadn't forgotten, we just unsure how to phrase it amid all the peevish typing I was doing. Couldn't think of any specific examples.
People just don't realize that the path of technology is almost ALWAYS military -> business -> consumer. Wars have resulted in tremendous advances in techology. The bigger the war, the greater the advances. Some examples of military technology now used for consumer applications:
* computers
* computer networking
* cellular phone technology
* jet airplanes (even prop planes too - the Wright brothers worked for the military in WWI)
* rockets, space travel (perhaps not consumer-level yet but SOON)
* nuclear technology
Nothing -- and I mean NOTHING -- quite gets the mind racing to invent like contemplation of one's one mortality or enslavement.
I support the guy's right to boycott anything he likes over principles and sort of admire it too, but I kind of hold it against him at the same time.
Yeah! He should also boycott the Internet which is based on research by DARPA! Nothing good comes from defense research!
12% C is 3.598 x 10^7 meters per second. To accelerate to that speed would require a very long time. Assuming you could accelerate at 10m/s^2 (1 G) it would take you 3.6 x 10^6 seconds which is about a month and a half. Obviously a chemical rocket can't burn for a month and a half. My understanding of the physics is pretty limited but I believe that a fission-fragment rocket is highly efficient (in terms of how much thrust you get per unit mass) with theoretical specific impulses possible between 100,000 and 1,000,000 but I don't think they provide enough thrust to accelerate an object weighing rougly a metric ton (or more if humans are involved) at 1G for a month and a half. The wikipedia article on specific impulse hints that such highly efficient engines tend to be limited in the amount of thrust they provide:
A variety of other non-rocket propulsion methods, such as ion thrusters, give much higher specific impulse but with much lower thrust; for example the Hall effect thruster on the SMART-1 satellite has a specific impulse of 1,640 s (16,100 m/s) but a maximum thrust of only 68 millinewtons. The hypothetical Variable specific impulse magnetoplasma rocket (VASIMR) propulsion would theoretically yield a minimum of 10,000300,000 m/s but would probably require a great deal of heavy machinery to confine even relatively diffuse plasmas, and so would be unusable for high-thrust applications such as launch from planetary surfaces.
The basic idea -- as I understand it -- is that these types of engines make very efficient use of their propellant's mass (lots of thrust per kg of propellant) but that they cannot create a lot of thrust at one time. They push weakly, but for extended periods of time at high efficiency.
I used to know how to do this kind of physics but now I can't. The exhaust velocity of fission-fragment engines is estimated at 3-5% C. If the plan is to reach 12% C, I think you need minimally 4 kg of propellant per kg of payload -- and in reality much more because the fuel you burn at first has to push not just the payload but the fuel to be used later as well.
Any physicists in the house?
How much fissionable material are you imagining we'll have for this fission fragment motor? Will not that enormous mass of fissionable material (enough to push for half the distance to A.C. and then decelerate the craft for the second half) not be itself an enormous encumbrance on your acceleration graphs, thus BADLY affecting your calculations? It's been a long time since I've done any related math, but I believe it takes an ENORMOUS amount of propellant to push something for 23 years. If I recall correctly, pushing the fuel itself is the essence of the problem. And forget about solar sails. Once you reach the (relatively close) heliopause, you can no longer rely on the sun for a push. There's basically no wind to sail on in deep space.
And, again, please don't get me wrong. I want interstellar travel to happen very badly. I have a serious love for romantic notions and sci fi. It's going to take a profound revolution in propulsion technology to change anything.
Our best bet is probably a TINY probe that somehow has enormous transmission capabilities. I'd start with something solar powered that can harness the energy of Alpha Centauri for transmission and work back from that.
PS: If you end up doing any math, please share. Would love to see it. My calculus muscles are badly atrophied.
Ahem. *bullshit*.
The heliopause, which has not yet been reached by Voyager 1 is apparently 23 x 10^9 km from earth. Alpha Centauri, the nearest star to our sun is 4.366 light years away which is 4.1306 x 10^13 km away.
If it has taken 38 years for Voyager 1 to reach the Heliopause, it would take 1,795.9 times as long to reach Alpha Centauri at that speed which comes out to something like 68,000 years. I'm assuming a couple of things of course:
* the speed so far is roughly the speed it will continue to travel
* it can escape the sun's gravitational well.
Suppose we are somehow miraculously able to accomplish the following:
* we send a system powerful enough to transmit an intelligible signal to us across 4.5 light years of space
* we somehow manage to travel 100 times faster than Voyager 1
You're still talking about roughly 680 years for it to get there. There might be some tiny relativistic effects that come into play, but I doubt they would alter the situation much. Are you sending humans? If so, you have to dramatically increase the weight of the vehicle to accommodate life-sustaining water/air/energy in which case you also need shit loads of propellant if you want to slow down on the other end. Forget entirely about the difficulty of insuring the survival of roughly 20 generations of humans against the problems of cosmic radiation and health and reproductive problems related to roughly a millenium spent weightless and getting fried by space rays.
"Quite tractable?"
You keep using that word. I do not think it means what you think it means.
~ Inigo Montoya
Are you out of your mind? Voyager 1, launched in 1977 hasn't even reached the heliopause and it doesn't need to contain any food, water, oxygen, or energy to support a single person. Don't get me wrong, I'm hoping for a breakthrough of some kind. The problem is *not* tractable.
Fine with me. Let them shoot their mostly rural population in the foot -- as long as the telcos give up the Universal Service Fund.
mod parent up. When you speak sense to certain folks, they hear crazy talk. And, conversely, crazy talk (e.g., anything said by pRick Santorum) makes sense to them.
My girlfriend keeps receiving spam mail from the Yahoo account of one of her deceased friends. Apparently the account has been compromised. Such a bummer.
*sigh*.
There were so many things backward about this I thought it was opposite day, not valentine's day: a Republican from Texas arguing for more spending by the federal government instead of privatization -- for science! WTF?
Thanks for bringing the facts.
oops...bad calculation. it's more like $7/watt. my bad. Still more than solar.
How does building another refinery result in a step toward energy independence? And how, exactly is this post 'insightful' ?
More importantly, are you sure this is the right thing to do? At $12 per watt ($14 billion, 2.2GW). That's several times more than the installed cost of solar, according to Lawrence Berkeley National Laboratory. And that doesn't include the cost of running the plant, disposing of radioactive waste that is a hazard for billions of years. Even if storage for this waste is dirt cheap, it would certainly add up over 4.5 x 10^9 years.