A fascinating proposal, but it lacks an important factor - steering.
A force radially away from the sun does very little for you. The solar wind force cancels a tiny portion of the solar gravity, with the result you end up in an orbit just slightly larger than before you turned on the sail.
To get anywhere, you need a component of force along your direction of motion. In 'traditional' solar sailing, this is achieved by putting the sail at 45 degrees to the solar radiation. If the tangential force acts in the direction of your motion, your orbit steadily grows. If it acts against your motion, your orbit shrinks.
So far as I can see, this proposal produces an approximately spherical 'sail'. This would not allow tilting the sail to produce a force component along the orbit. However, they don't discuss the shape of the bubble, so I may be going astray here.
As an aside - from memory, there is about 10 times as much pressure available from the sun's light as from the solar wind. This method doesn't use the light, whereas 'traditional' solar sailing does. This advantage is likely overwelmed by the ability to make a large 'sail' cheaply and lightly with the bubble method.
(My solar sailing experience is limited to setting an undergraduate assignment on the topic some years ago.)
Does anyone have any real statistics to show a link? A few people have noted that they have the impression that there is a correlation between geekiness and mysticism. This is purely anecdotal so far.
It is moderately likely on the grounds that geeks tend to be non-conformist (so I can use anecdotal evidence too) which will increase the percentage of both atheists and mystics compared to the general population.
To my mind, a more pernicious questionable link is geeks and libertarianism.
I am an atheist (closely linked to a scientific world view/philosophy), middle-left politically, pro-gun control (and fortunately living in a country with fairly good gun laws.)
About all I could think about while watching "Independence Day" was how it was crying out for MST3King - and I'd only seen MST3K twice at the time. Given that it only took 40 comments before someone else brought this up, I suspect it is a common sentiment. (To add another to the list: 'Deep Impact': so they made caverns for 5 million people to live in for several years and kept it a total secret until the president announced it?)
I must be getting cynical in my old age, but when I see this the first thing that occurs to me is somebody is going to rig a little circuit to take a photo once every 20 seconds, and hide it in changing rooms/toilets/whatever.
I was told CalTech and Wolfram had a disagreement over who owned the machine, and Caltech moved it to the most inaccessable place they owned to try to keep it. (I take no responsibility for the accuracy of this statement.)
Another cute feature was the reel to reel tape drive - an old but still used technology at the time. They had a particularly old drive, because all the new ones would auto-feed the tape for you using suction, and they wouldn't work at ~4200m altitude.
On environmental effects of exploiting solar energy: Yes, everything has an environmental cost, but what I see here is a lot of retoric and no numbers.
The energy flux from the sun at the Earth's orbit is about 1 kW/m^2. Given that not all of the Earth's surface is perpendicular to the sun's rays at all times, this means on average we need 4 m^2 of surface area to get 1 kW. (This includes the fact it is night some of the time.)
How efficiently can we convert sunlight to electricity? I think solar electric panels are about 25% efficient (I'd welcome correction) meaning 16m^2 per kW.
What is our per-capita energy consumption? I'm guessing here, but in industrialized countries, probably a few kW - say 4, bringing us to 64m^2 per person. Multiply by 6e9 people, divide by surface area of the Earth and I get.08%.
Assuming we only do this on land, and land is about 20% of the Earth's surface, this is 0.4% of the land area.
This isn't too bad, but is too much to be dismissed out of hand as having negligible environmental effect. Does anyone else have better numbers?
Some factors that make the situation worse: Whatever it is will need to use easily accessible land, which is much rarer than land in general. This also ignores the energy cost of producing the solar power stations. I understand this is a killer for semiconductor solar electric panels currently - they take about 30 years to pay back the energy used in their production.
The article states "We discovered that the game that inspired our work is still protected under copyright (all these years later)."
You'll be lucky if your grandchildren get to play the original unencumbered by copyright before retirement age. It lasts something like life-of-author plus 70 years.
I remember another name-mangled clone from long ago: 'Taxman' on the Apple II. One of my first hacks was to find the ghost images in this game and replace them by pictures of a disk drive, monitor, floppy and joystick.
A minor point - I've seen plenty of articles bemoaning the lack of men in early childhood care/education. I've seen more bemoaning the lack of women in technical fields, but this is biased by my choice of reading. If I read periodicals with names like 'Early Childhood Education Review' or 'Schools Today' rather than 'New Scientist' and slashdot, I expect the number of articles would go the other way.
An interesting parallel comes to mind here. In about 1974, a Turkish Airways DC-10 crashed near Paris because of an inproperly closed cargo bay door. Some people have tried to blame the accident on the baggage handler who closed the door.
There are a number of problems with this allocation of blame, but the fundamental one is this: Air traffic controllers and pilots are highly trained and highly paid to ensure air safety. Baggage handlers are not. If a baggage handler can make an error that kills 350 people, it is the fault of the system for allowing this, not the baggage handler. (McDonnell Douglas were correctly held to be responsible for the Paris crash.)
Similarly, passengers are not trained or paid to be aviation safety experts. If an untrained passenger using a cell phone at the wrong time causes the plane to crash, it is primarily the fault of the plane, not the passenger.
(Having said this, the bans will have to remain in place until the old planes are retired.)
There is one fairly simple change I would like to see: a distinction between means and ends, and recognition that the patentability of each could be different.
For example, the first time I realized the patent system was out of control was when I read in New Scientist that a company had succeeded in genetically engineering cotton for the first time and had patented *all genetic engineering of cotton*.
Here we have a case where the means was inobvious and patentable, but the end (genetically engineered cotton) was obvious and should not have been patentable. Similarly, patents such as "selling music downloads over the internet" should not be patentable, but implementation details possibly should be.
A reverse example is the Hula Hoop. It was not at all obvious that this object was desirable, but once you know what it is, how to make it is obvious. Nobody should be able to make Hula Hoops by other methods, but the Hula Hoop patent (assuming it exists) should not prevent people from using loops of hose in other ways.
(Of course IANAL. Perhaps the distinction exists already, but the patents I see being granted doesn't give me any confidence that it does.)
I did some mental calculations when I read the article:
10 trillion writes = 10^13 Maximum write rate on a PC approx 100MHz = 10^8/s Therefore, minimum time before write cycle exhausted = 10^5s which is about a day.
Put like this, it isn't very impressive. Of course, nobody is going to write bits quite that fast with current technology. If a computer has 100Mb memory and writes byte to a random location (a major assumption) 10^9 times a second (1 GHz) then each byte changes about 10 times a second, and the memory lasts 10^12 seconds, which is 'ample' (over 1000 years.)
There may have to be some twiddling to ensure some parts of the memory don't get hit much more often than others.
Even if the lifetime is only 5 years, I can live with replacing my memory that often.
The article gives no information on the planned trajectory. From my 'vast' experience in solar sailing and celestial mechanics (I set an assignment once on solar sail propulsion for a second year university astronomy course) I'll do some speculating. Both light intensity (hence thrust) and solar gravity drop as an inverse square law with distance from the sun - so the ratio is constant. Unless the thrust-to-gravity ratio is greater than one (very unlikely), you can't simply put your sail perpendicular to the sun's rays and sail out of the solar system. In the approximation of circular orbit and small thrust-to-gravity, the optimal orientation is to angle the sail at 45 degrees to the sun's rays, pointing along the orbit (to gain energy and increase orbit size) or back (to decrease orbit size.) If we ever have solar sail tugs making slow interplanetary journeys, this is how they will operate - however, this method can never give you solar escape velocity. To get high delta-v (change in velocity), you need to go close to the sun. I would expect this mission to aim for a highly elliptical orbit to get most of it's delta-v on one or more close approaches to the sun. The last such approach gains sufficient energy to make the orbit hyperbolic and escape the sun. The initial elliptical orbit will almost certainly be achieved by a gravity-assist from a planet - probably Earth or Venus.
"A Boeing software engineer has patented a basic method of correcting the century in dates stored in databases and sent a threatening form letter to 700 of the nation's largest corporations (including The New York Times), demanding one-fourth of a percent of their total revenues, on the assumption that they probably have used the same method."
So this idea is so innovative and non-obvious that it deserves a patent, but companies who have never heard of this person and their patent probably chose to use this method.
Either somebody's university didn't require a course in elementary logic, or (more likely based on the attitude shown here) somebody cheated their way through it.
I just thought of a more sinister related problem: I could create a trojan program and fiddle it to match the checksum (and if necessary file length) of the latest SETI@Home client (for example.) I then get this file onto as many computers as possible. If the target computer has SETI@Home already installed, my file gets SIS linked to it and morphs harmlessly into SETI@Home. However, if I get there first, and someone subsequently installs SETI@Home, it morphs into my evil trojan.
This could be avoided by two ways: if the SIS program does a bit-by-bit comparison before linking two files, or if it uses a cryptographic/one way checksum algorithm (i.e. it is very hard for me to fiddle my trojan to match a predetermined checksum.)
I wonder how big their checksums are, and whether once they find a checksum match, they follow up with a bit-by-bit comparison before linking two files?
If you have 32 bit checksums (4 billion numbers) then you only need about 65,000 files before you expect two to have a matching checksum by chance. (A similar point was made in the comments to a story about DNA matching from about a month ago.)
Imagine the damage if your annual report happens to have the same checksum as something from your porn collection, and they get linked.
Firstly, "The Crysalids" has long been one of my favourite books.
Secondly, this 'dumbing down' of titles can go both ways. A strong contender for my favourite book of all time, "This Star Shall Abide" by Sylvia Engdahl was renamed in UK/Commonwealth edition to "The Heritage of the Star."
(Plug: like Crysalids, this is a young adult SF novel with a young man taking a moral stand against an oppresive religious society. It has just been republished (along with its sequels) by Meisha Merlin as Children of the Star. If you like The Crysalids, you will love this one.)
I want the number of cables to be the same as the number of computer thingees (speakers, modems, monitors etc) I have. Power and signal should use the same cable. This would reduce clutter enormously.
I'm not sure which of the competing serial standards achieve this, but it is impressive that the computer-guts pictures in the article show that they not only eliminated the ribbon cables, but the thumb-thick bundle of power wires also.
"I don't know much about hardware, but I know what I like"
We in New Zealand have beaten the British once again. A similar DNA analysis linked a man to two seperate crimes - the slight problem being that as he was in prison in a different city, he had a (literally) cast iron alibi. This differs from the British case in that it was presumably a lab contamination problem rather than chance match.
I think the previous poster is confusing this with the Doherty case. About 6(?) years ago, an 11 year old girl was raped in her room at night. She positively identified Doherty, a neighbour, as the rapist. About 2(?) years ago he was released when advances in DNA testing were able to show that he was not responsible.
In another recent controversial, high profile murder case, evidence included some hairs found on the accused's yacht, with a DNA match to one of the victims. The defense pointed out various possibilities for contamination in the lab. The accused was found guilty, but only the jury know how much weight was put on the DNA evidence.
Thanks for the link. It is interesting applying hindsight to the timing of the HURD release. (These were writen in early 1992) (And yes, first available pre-loaded on computers is not the same as first release of a useful version.)
Linus Torvalds: "If the GNU kernel had been ready last spring, I'd not have bothered to even start my project: the fact is that it wasn't and still isn't. Linux wins heavily on points of being available now."
Linus Torvalds: "If you write programs for linux today, you shouldn't have too many surprises when you just recompile them for Hurd in the 21st century."
Andy Tanenbaum: "5 years from now everyone will be running free GNU on their 200 MIPS, 64M SPARCstation-5."
So Linus was spot on or a year pessimistic on the 21st centuary prediction, depending on whether he is a pedant or not. I *still* don't have 64M on my home computer, although the O2 I use at work is about to be upgraded to 256M. Sun went non-linear on their numbering of SPARCstations, so I don't know how that pans out.
Slashdot Mirror
A force radially away from the sun does very little for you. The solar wind force cancels a tiny portion of the solar gravity, with the result you end up in an orbit just slightly larger than before you turned on the sail.
To get anywhere, you need a component of force along your direction of motion. In 'traditional' solar sailing, this is achieved by putting the sail at 45 degrees to the solar radiation. If the tangential force acts in the direction of your motion, your orbit steadily grows. If it acts against your motion, your orbit shrinks.
So far as I can see, this proposal produces an approximately spherical 'sail'. This would not allow tilting the sail to produce a force component along the orbit. However, they don't discuss the shape of the bubble, so I may be going astray here.
As an aside - from memory, there is about 10 times as much pressure available from the sun's light as from the solar wind. This method doesn't use the light, whereas 'traditional' solar sailing does. This advantage is likely overwelmed by the ability to make a large 'sail' cheaply and lightly with the bubble method.
(My solar sailing experience is limited to setting an undergraduate assignment on the topic some years ago.)
It is moderately likely on the grounds that geeks tend to be non-conformist (so I can use anecdotal evidence too) which will increase the percentage of both atheists and mystics compared to the general population.
To my mind, a more pernicious questionable link is geeks and libertarianism.
I am an atheist (closely linked to a scientific world view/philosophy), middle-left politically, pro-gun control (and fortunately living in a country with fairly good gun laws.)
About all I could think about while watching "Independence Day" was how it was crying out for MST3King - and I'd only seen MST3K twice at the time. Given that it only took 40 comments before someone else brought this up, I suspect it is a common sentiment. (To add another to the list: 'Deep Impact': so they made caverns for 5 million people to live in for several years and kept it a total secret until the president announced it?)
I was told CalTech and Wolfram had a disagreement over who owned the machine, and Caltech moved it to the most inaccessable place they owned to try to keep it. (I take no responsibility for the accuracy of this statement.)
Another cute feature was the reel to reel tape drive - an old but still used technology at the time. They had a particularly old drive, because all the new ones would auto-feed the tape for you using suction, and they wouldn't work at ~4200m altitude.
I have a solution: product placement! E.g.
Imagine there's no heaven
It's easy if you try.
Air-sole Nikes below us
Above us only sky.
Imagine all the people
holidaying in LA.
Woohooo
You may think I'm a dreamer
But I'm not the only one
I hope one day you'll try out
An Acme matress and have some fun.
The energy flux from the sun at the Earth's orbit is about 1 kW/m^2. Given that not all of the Earth's surface is perpendicular to the sun's rays at all times, this means on average we need 4 m^2 of surface area to get 1 kW. (This includes the fact it is night some of the time.)
How efficiently can we convert sunlight to electricity? I think solar electric panels are about 25% efficient (I'd welcome correction) meaning 16m^2 per kW.
What is our per-capita energy consumption? I'm guessing here, but in industrialized countries, probably a few kW - say 4, bringing us to 64m^2 per person. Multiply by 6e9 people, divide by surface area of the Earth and I get .08%.
Assuming we only do this on land, and land is about 20% of the Earth's surface, this is 0.4% of the land area.
This isn't too bad, but is too much to be dismissed out of hand as having negligible environmental effect. Does anyone else have better numbers?
Some factors that make the situation worse: Whatever it is will need to use easily accessible land, which is much rarer than land in general. This also ignores the energy cost of producing the solar power stations. I understand this is a killer for semiconductor solar electric panels currently - they take about 30 years to pay back the energy used in their production.
You'll be lucky if your grandchildren get to play the original unencumbered by copyright before retirement age. It lasts something like life-of-author plus 70 years.
I remember another name-mangled clone from long ago: 'Taxman' on the Apple II. One of my first hacks was to find the ghost images in this game and replace them by pictures of a disk drive, monitor, floppy and joystick.
A minor point - I've seen plenty of articles bemoaning the lack of men in early childhood care/education. I've seen more bemoaning the lack of women in technical fields, but this is biased by my choice of reading. If I read periodicals with names like 'Early Childhood Education Review' or 'Schools Today' rather than 'New Scientist' and slashdot, I expect the number of articles would go the other way.
There are a number of problems with this allocation of blame, but the fundamental one is this: Air traffic controllers and pilots are highly trained and highly paid to ensure air safety. Baggage handlers are not. If a baggage handler can make an error that kills 350 people, it is the fault of the system for allowing this, not the baggage handler. (McDonnell Douglas were correctly held to be responsible for the Paris crash.)
Similarly, passengers are not trained or paid to be aviation safety experts. If an untrained passenger using a cell phone at the wrong time causes the plane to crash, it is primarily the fault of the plane, not the passenger.
(Having said this, the bans will have to remain in place until the old planes are retired.)
For example, the first time I realized the patent system was out of control was when I read in New Scientist that a company had succeeded in genetically engineering cotton for the first time and had patented *all genetic engineering of cotton*.
Here we have a case where the means was inobvious and patentable, but the end (genetically engineered cotton) was obvious and should not have been patentable. Similarly, patents such as "selling music downloads over the internet" should not be patentable, but implementation details possibly should be.
A reverse example is the Hula Hoop. It was not at all obvious that this object was desirable, but once you know what it is, how to make it is obvious. Nobody should be able to make Hula Hoops by other methods, but the Hula Hoop patent (assuming it exists) should not prevent people from using loops of hose in other ways.
(Of course IANAL. Perhaps the distinction exists already, but the patents I see being granted doesn't give me any confidence that it does.)
10 trillion writes = 10^13
Maximum write rate on a PC approx 100MHz = 10^8/s
Therefore, minimum time before write cycle exhausted = 10^5s which is about a day.
Put like this, it isn't very impressive. Of course, nobody is going to write bits quite that fast with current technology. If a computer has 100Mb memory and writes byte to a random location (a major assumption) 10^9 times a second (1 GHz) then each byte changes about 10 times a second, and the memory lasts 10^12 seconds, which is 'ample' (over 1000 years.)
There may have to be some twiddling to ensure some parts of the memory don't get hit much more often than others.
Even if the lifetime is only 5 years, I can live with replacing my memory that often.
The article gives no information on the planned trajectory. From my 'vast' experience in solar sailing and celestial mechanics (I set an assignment once on solar sail propulsion for a second year university astronomy course) I'll do some speculating. Both light intensity (hence thrust) and solar gravity drop as an inverse square law with distance from the sun - so the ratio is constant. Unless the thrust-to-gravity ratio is greater than one (very unlikely), you can't simply put your sail perpendicular to the sun's rays and sail out of the solar system. In the approximation of circular orbit and small thrust-to-gravity, the optimal orientation is to angle the sail at 45 degrees to the sun's rays, pointing along the orbit (to gain energy and increase orbit size) or back (to decrease orbit size.) If we ever have solar sail tugs making slow interplanetary journeys, this is how they will operate - however, this method can never give you solar escape velocity. To get high delta-v (change in velocity), you need to go close to the sun. I would expect this mission to aim for a highly elliptical orbit to get most of it's delta-v on one or more close approaches to the sun. The last such approach gains sufficient energy to make the orbit hyperbolic and escape the sun. The initial elliptical orbit will almost certainly be achieved by a gravity-assist from a planet - probably Earth or Venus.
So this idea is so innovative and non-obvious that it deserves a patent, but companies who have never heard of this person and their patent probably chose to use this method.
Either somebody's university didn't require a course in elementary logic, or (more likely based on the attitude shown here) somebody cheated their way through it.
This could be avoided by two ways: if the SIS program does a bit-by-bit comparison before linking two files, or if it uses a cryptographic/one way checksum algorithm (i.e. it is very hard for me to fiddle my trojan to match a predetermined checksum.)
If you have 32 bit checksums (4 billion numbers) then you only need about 65,000 files before you expect two to have a matching checksum by chance. (A similar point was made in the comments to a story about DNA matching from about a month ago.)
Imagine the damage if your annual report happens to have the same checksum as something from your porn collection, and they get linked.
Secondly, this 'dumbing down' of titles can go both ways. A strong contender for my favourite book of all time, "This Star Shall Abide" by Sylvia Engdahl was renamed in UK/Commonwealth edition to "The Heritage of the Star."
(Plug: like Crysalids, this is a young adult SF novel with a young man taking a moral stand against an oppresive religious society. It has just been republished (along with its sequels) by Meisha Merlin as Children of the Star. If you like The Crysalids, you will love this one.)
.
I'm not sure which of the competing serial standards achieve this, but it is impressive that the computer-guts pictures in the article show that they not only eliminated the ribbon cables, but the thumb-thick bundle of power wires also.
"I don't know much about hardware, but I know what I like"
I think the previous poster is confusing this with the Doherty case. About 6(?) years ago, an 11 year old girl was raped in her room at night. She positively identified Doherty, a neighbour, as the rapist. About 2(?) years ago he was released when advances in DNA testing were able to show that he was not responsible.
In another recent controversial, high profile murder case, evidence included some hairs found on the accused's yacht, with a DNA match to one of the victims. The defense pointed out various possibilities for contamination in the lab. The accused was found guilty, but only the jury know how much weight was put on the DNA evidence.
What scares me is that I may live to see a time when no living person has set foot on another world. This would be a tremendous tragedy.
Can we use this exploit to randomly overwrite people's doubleclick cookies? :-)
Linus Torvalds: "If the GNU kernel had been ready last spring, I'd not have bothered to even start my project: the fact is that it wasn't and still isn't. Linux wins heavily on points of being available now."
Linus Torvalds: "If you write programs for linux today, you shouldn't have too many surprises when you just recompile them for Hurd in the 21st century."
Andy Tanenbaum: "5 years from now everyone will be running free GNU on their 200 MIPS, 64M SPARCstation-5."
So Linus was spot on or a year pessimistic on the 21st centuary prediction, depending on whether he is a pedant or not. I *still* don't have 64M on my home computer, although the O2 I use at work is about to be upgraded to 256M. Sun went non-linear on their numbering of SPARCstations, so I don't know how that pans out.