If you're going to have a huge oxygen tank to supply an ineffient internal combustion engine, and something to store the leftover CO2, you might as well just use fuel cells. It would be about 100 times more efficient, and give you more power per $ and kilogram
Nevertheless, it would be impossible to significantly exceed the sun's escape velocity, because as the speed increases it would spiral away from the sun and lose thrust. Several probes running on concentional rockets have already achieved escape velocity from the solar system. Solar sails are only good for saving fuel on intrastellar travel within an AU or two of the sun.
If laser propulsion weren't wildly inefficient...
on
Solar Sail Fails Again
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· Score: 2
...your laser pen would push itself across your desk.
The propulsive force of light is only a tiny fraction of the energy carried by it. Therefore, using an orbital laser to push the solar sail once it got out of the sun's range would be wildly inefficient.
It would also be extremely difficult to develop the proper targeting mechanism. Do you haver any idea how hard it is to hit a 1 meter cross section from a light year away?
tan^-1(1/(9.46*10^12))= 1.057*10^-13
The laser would have to be accurate to within a ten trillionth of a degree. The earth's own gravitational field bends light more than that. And, since it would take a year for its image to reach us, and another year+ for the laser to reach it, the course would have to be extrapolated 2+ years ahead. That could create major problems.
Nevertheless, the fact remains that it is physically impossible for it to get going more that slightly faster than escape velocity from the sun, because as it builds up speed, it would migrate to a larger orbit. Using lasers to boost it would be wildly inefficient, because the momentum imparted by the light would only be an infinitesimal fraction of it's energy.
I'm reasonably certain that light cannot exert propulsive force, and even if it does, the force is less than a billionth of the energy put into the laser. Otherwise the flash on your camera would have a noticable kick to it.
Well, the way for it to achieve the maximum possible velocity would be to maneuver into a highly eliptical orbit around the sun, and then after passing the closest point of it's orbit, align the solar sails to create the maximum thrust. Even then, it would only be able to slightly exceed escape velocity from the sun. Conventional rockets can (and have) already done that. Solar sails are wildly impractical except for travel within 1 or 2 AU of the sun.
Light (photons) have no propulsive force, because they have no mass. The propulsive force of the solar sail will come from Protons and Helium nuclei that are ejected from the sun at high sub-light speeds.
The problem is, it would have to stay close to the sun to get much thrust. To stay close to the sun, it would have to maintain a low speed. It could never get going fast enough to travel interstellar distances any faster than the rockets we already have.
That's about $8 million. That's a hell of an expensive boat, considering it's size. You could make a full scale solid 24K gold replica of it for that price!
Laser show programming? Almost nobody hasd the equipment for that, and if they do, they probably already have the tools to program it. This definitely isn't something that most people should care about. Why is this posted on slashdot, instead of some laser show programmers newsgroup? Is is a slow news day?
Or was CmdrTaco assimilated?
"I am CmdrTaco of Borg. Relevance is irrelavent. You will be annoyed by pointless articles." ;)
How could any star system possibly not have water? Hydrogen is the most common element in the universe, and Oxygen is a common element created in mass quantities in every supernova. It's practically impossible to have a star system without plenty of water in it.
Even if magnetic hard drives max out around 300 GB or so, how could you possibly need more space than that? I've managed to survive with a 6 GB hard drive this long. What useful purpose, if any, could an average person have for a terabyte or larger hard drive?
safeweb.com is a free proxy service that will work with any Java-compatible browser. It lets you disable popups, cookies, malicious scripts, and whatever else you want to. It also hides your IP address.
It completely sucked. Remember IJ & The Temple of Doom? It was written and directed by George Lucas, and IMO, it was terrible. Lucas just doesn't have style.
The Lawyers' nastygram said the websites were violating the Federal Trademark Dillution Act. Here's what that law actually says:
(1) Any person who, on or in connection with any goods or services, or any container for goods, uses in commerce any word, term, name, symbol, or device, or any combination thereof, or any false designation of origin, false or misleading description of fact, or false or misleading representation of fact, which...
As you can see, this only applies to unauthorized commercial uses of a registered trademark. These websites do not qualify as commercial uses, therefore they have no legal basis to sue the anti-barney sites.
IMHO, frivolous litigation about "intellectual property" infringement has gone way too far. The DMCA should be abolished, and all copyrights should be limited to 6 years.
This country is pathetic. It's turning into a lawyerocracy...
*sigh*
A better flamethrower design
on
Water Guns
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· Score: 1
Fill it up with strong vodka or Everclear. That will make a nice flamethrower, and it won't melt the plastic, because alchohol burns (and vaporizes) at a low temperature. Pure Ethanol vaporizes around 70 degrees C.
Slashdot Mirror
WARNING!!! goatse.cx link! mod it down! He's using the same trick as that other post on the last article!
This is GUI!
You could just use a specialized screen capture tool while playing the movie. It's virtually impossible for them to avoid that method of ripping it.
If you're going to have a huge oxygen tank to supply an ineffient internal combustion engine, and something to store the leftover CO2, you might as well just use fuel cells. It would be about 100 times more efficient, and give you more power per $ and kilogram
There's a major new M$ based virus every week. This hardly qualifies as news.
Nevertheless, it would be impossible to significantly exceed the sun's escape velocity, because as the speed increases it would spiral away from the sun and lose thrust. Several probes running on concentional rockets have already achieved escape velocity from the solar system. Solar sails are only good for saving fuel on intrastellar travel within an AU or two of the sun.
...your laser pen would push itself across your desk.
The propulsive force of light is only a tiny fraction of the energy carried by it. Therefore, using an orbital laser to push the solar sail once it got out of the sun's range would be wildly inefficient.
It would also be extremely difficult to develop the proper targeting mechanism. Do you haver any idea how hard it is to hit a 1 meter cross section from a light year away?
tan^-1(1/(9.46*10^12))= 1.057*10^-13
The laser would have to be accurate to within a ten trillionth of a degree. The earth's own gravitational field bends light more than that. And, since it would take a year for its image to reach us, and another year+ for the laser to reach it, the course would have to be extrapolated 2+ years ahead. That could create major problems.
no, that is a thermal effect on the low pressure gas in the bulb, which is a hell of a lot stronger that what the solar sail will use.
Nevertheless, the fact remains that it is physically impossible for it to get going more that slightly faster than escape velocity from the sun, because as it builds up speed, it would migrate to a larger orbit. Using lasers to boost it would be wildly inefficient, because the momentum imparted by the light would only be an infinitesimal fraction of it's energy.
I'm reasonably certain that light cannot exert propulsive force, and even if it does, the force is less than a billionth of the energy put into the laser. Otherwise the flash on your camera would have a noticable kick to it.
Well, the way for it to achieve the maximum possible velocity would be to maneuver into a highly eliptical orbit around the sun, and then after passing the closest point of it's orbit, align the solar sails to create the maximum thrust. Even then, it would only be able to slightly exceed escape velocity from the sun. Conventional rockets can (and have) already done that. Solar sails are wildly impractical except for travel within 1 or 2 AU of the sun.
Light (photons) have no propulsive force, because they have no mass. The propulsive force of the solar sail will come from Protons and Helium nuclei that are ejected from the sun at high sub-light speeds.
DUH!!!
The problem is, it would have to stay close to the sun to get much thrust. To stay close to the sun, it would have to maintain a low speed. It could never get going fast enough to travel interstellar distances any faster than the rockets we already have.
That's about $8 million. That's a hell of an expensive boat, considering it's size. You could make a full scale solid 24K gold replica of it for that price!
Sure, cable is really slow at peak times. If you're like me, and download everything at 4am, it's not a problem. :)
Laser show programming? Almost nobody hasd the equipment for that, and if they do, they probably already have the tools to program it. This definitely isn't something that most people should care about. Why is this posted on slashdot, instead of some laser show programmers newsgroup? Is is a slow news day?
;)
Or was CmdrTaco assimilated?
"I am CmdrTaco of Borg. Relevance is irrelavent. You will be annoyed by pointless articles."
What did you expect? The whole world's full of corrupt SOBs. Just use a different search engine if you don't like it.
Google: every geek's favorite search engine
Scientists still need to figure out what each gene does and how they interact before they can do something useful with the human genome.
How could any star system possibly not have water? Hydrogen is the most common element in the universe, and Oxygen is a common element created in mass quantities in every supernova. It's practically impossible to have a star system without plenty of water in it.
Even if magnetic hard drives max out around 300 GB or so, how could you possibly need more space than that? I've managed to survive with a 6 GB hard drive this long. What useful purpose, if any, could an average person have for a terabyte or larger hard drive?
That's a load of bullshit. No one can go 330 miles a day on a bike, especially not for 8 consecutive days.
safeweb.com is a free proxy service that will work with any Java-compatible browser. It lets you disable popups, cookies, malicious scripts, and whatever else you want to. It also hides your IP address.
It completely sucked. Remember IJ & The Temple of Doom? It was written and directed by George Lucas, and IMO, it was terrible. Lucas just doesn't have style.
The Lawyers' nastygram said the websites were violating the Federal Trademark Dillution Act. Here's what that law actually says:
...
(1) Any person who, on or in connection with any goods or services, or any container for goods, uses in commerce any word, term, name, symbol, or device, or any combination thereof, or any false designation of origin, false or misleading description of fact, or false or misleading representation of fact, which
As you can see, this only applies to unauthorized commercial uses of a registered trademark. These websites do not qualify as commercial uses, therefore they have no legal basis to sue the anti-barney sites. IMHO, frivolous litigation about "intellectual property" infringement has gone way too far. The DMCA should be abolished, and all copyrights should be limited to 6 years. This country is pathetic. It's turning into a lawyerocracy... *sigh*
Fill it up with strong vodka or Everclear. That will make a nice flamethrower, and it won't melt the plastic, because alchohol burns (and vaporizes) at a low temperature. Pure Ethanol vaporizes around 70 degrees C.