Once the Nitrogen and water problems are solved, the biggest issue is how to approach the bootstrapping of a colony. Doing something simple like making glass or steel is nigh impossible without the infrastructure to support it. And can we really afford to be shipping an entire infrastructure for the kind of high-tech materials fabrication that life on an alien planet would require? 1) Build self-replicating factories on the moon. (Plans for this have existed since the Carter administration.) 2) Build a lunar mass driver to launch bricks and I-beams (plus other infrastructure items) to Mars. 3) Build a Mars base, modeled after Biosphere One. Operate it for at least one Martian year without humans. 4) Send 12-25 people, aged 65+, with enough supplies to spend the rest of their lives on Mars. (Not having to return will drasticly reduce the mission cost.) 5) ??? (Evalute feasibility of sending younger colonists.) 6) Profit!!!
Note that this plan will require no human space flight beyond low Earth orbit prior to step 4. It should be possible to reach step 4 within twenty years of implementation.
Lots of reputable physicists have speculated that the fundamental physical constants have varied over the life of the Universe, although those theories do tend to get knocked down pretty quickly. See http://en.wikipedia.org/wiki/Variable_speed_of_light for an overview.
On a related note, http://en.wikipedia.org/wiki/Big_Rip speculates that gravity may not work at distances over 46.5e9 light years, and that that distance is decreasing over time. If true, then eventually "all hell breaks loose".
Go ahead and learn the 2.x version. The 3.0 version isn't much different, and the differences are usually trivial. For example, any time there are two version of a function in 2.x, one of which starts with an 'x', it's almost always the 'x' version that you want to use. So go ahead and do so; all that happens in 3.0 is that the 'x' will go away. The only other major change is that the print statement becomes a function, and the 2to3.py converter will handle that conversion just fine.
It's sorta like debating which movie studio makes the best movies. Does total count? High signal to noise ratio? Do we adjust for overall popularity? Our feelings as they've changed with time?
You don't need to detonated perfectly, just enough to make a pretty big boom. If you have a 10 megaton nuclear device, and you only manager to figure out how to make it have a.1 megaton explosion, you still have a pretty dangerous weapon.
My understanding is that even that is hard. A modern A-bomb consists of a spherical shell of uranium with multiple explosive charges surrounding it. When the charges are set off, they crumple the shell into a solid sphere and it goes BOOM. Due to (probably intentional) variances in the manufacturing process, the charges can't be detonated at the same time, but must be set off in a special order with delays of several milliseconds. Cleverly, the firing code used to detonate is the list of these delays; the only way to determine the validity of a code is to try using it and see if you get a BOOM or a fizzle (i.e., everything melts and you're left with a puddle of molten uranium/iron alloy). Which means that if you ever manage to steal a bomb, your best bet is to disassemble it and recast the uranium into two half-spheres which you then slap together at high speed.
I frequently lay my cellphone next to my keyboard. Then, when I want to use the mouse, I'll accidentally grab the phone instead. After wasting a few cycles wondering why the cursor isn't responding, I look at my hand, place the cell phone a bit father from the keyboard, and grab the real mouse. It's only embarrassing if someone is looking over my shoulder.
The biggest industrial process will involve the casting of paving stones and Lego-like components from molten rock. The only limiting factor for self-replication is chlorine, which is needed to refine aluminum from lunar materials. The other elements that you mention may not be plentiful in any absolute sense, but they are plentiful enough. For example, Helium-3 is present at concentrations on the order of 0.01 ppm, but there are serious proposals from China and Russia to mine that; by comparison, those other gases are easy to extract.
The paper goes into much detail, but little AI will be required. Most of the time, the machinery will require no more AI than an auto assembly line; when more intellegence is required, humans would teleoperate the equipment in much the same way that we currently control the Mars Exploration Rovers.
The initial seed factory was designed with two copies of everything vital, and will spend its first year building itself out before it attempts its first replication. Again, I point to the examples of Spirit and Opportunity, operating for four years now in a much harsher environment.
I'm not sure what your point is. The graph is from the paper I cited, and the authors go into some detail on how the various sub-processes will fit together. Yes, those "C"s, "F"s, "N"s, "P"s, and "H"s are only present in miniscule quantities on the moon, but a robotic manufacturing operation won't require large quantities of them to self-replicate. After a few years, you'll have dozens of self-repairing facilities operational, and then you'll shift to producing consumables for human tourists.
The Apollo Lunar Module massed about 15000 Kg, including fuel. What actually landed on the moon was pretty close to 7000 Kg.
My bad. I misinterpreted this quote from the paper: "100 tons is a credible system mass in terms of foreseeable NASA launch capabilities to the lunar surface, representing very roughly the lunar payload capacity of four Apollo missions to the Moon."
If it had been designed purely for dropping a payload on the moon, the payload would have been comparable in size to the Ascent Module, which massed about 4700 Kg.
I'm going to go out on a limb here, but according to Wikipedia, the Saturn V delivered about 47,000 kg to lunar orbit. That's 51.7 tons. Using the same ratioo as the LM, that gives you a bit over 24 tons landing on the moon. Also note that each mission delivered more mass to orbit than its immediate predecessor (each trip stayed longer and brought back more rocks, and NASA started shipping lunar buggies as well). So while my interpretation was off, the number still looks reasonable.
NASA has been looking into self-replicating lunar factories since at least 1980. http://www.islandone.org/MMSG/aasm/AASM53.html presents a proposal for a 100-ton "seed" factory that could replicate itself in one year, using 5-10 tons (per replica) of "vitamin" components supplied from Earth. (For comparison, the Apollo lunar lander delivered ~25 tons to the lunar surface.) We now know much more about the lunar surface, so some parts of the proposal need to be tweaked, but MIT has been running workshops on self-replicating equipment for the past several years; it should be possible to get such a factory built and delivered with minimal effort.
This isn't good for a flight to Asia unless you get a seat with a power socket, which I think exists nowadays in many planes, even in Coach. Just to but this into perspective, I recently made my first (and to date only) trans-Atlantic flights, flying coach on Delta and Air France between Atlanta and Paris. I was pleasantly surprised by the quality of the seating, which was comparable to business-class on domestic flights. Because of this, I'd fully expect there to be power outlets available in any trans-oceanic flight. (Also, try to fly in planes operated by European operators; they serve complimentary wine with their meals.)
I need wired because we don't have wireless at work for reasonable issues Does your workplace support VPN access from home? If so, then how about suggesting to your network security guys that they install a WAP *outside* of the corporate firewall? This would allow you to use your existing VPN infrastructure to tunnel into the workplace, and the security issues would be exactly what they've already come to terms with.
We'll see people buying cheap 4 TB drives a couple years from now, but as is most basic users can't fill the 40 gigs. Why do they need more than a few gigs for a few dollars?
Are you saying that most users don't have access to porn newsgroups and/or ripped DVDs? LifeBits can be expected to generate a lot of data, as well.
I'd use unionfs to mount a tmpfs on top of your SSD for log files and such. Have cron run snapmerge periodically to copy the changes back to the SSD. This will let your SSD enjoy a long and useful life. See http://www.linuxjournal.com/article/7714#N0xa50890.0xdfb370 for more info.
The key is the utility of the software, not its price. If something provides an advantage over their competition, your customer won't be inclined to give it away. In fact, most customers aren't interested in getting involved in the even minor requirements imposed by the GPL, i.e. making the source available to whomever they sell it to, so they won't be interested in distributing it at all; in their view, the cost of doing so exceeds the benefits. And don't forget that you've only sold the source to the company, not its employees. If someone uploads your code to Sourceforge, they're not only guilty of GPL violations, they've also stolen property from their employer.
I read the first few links OK, then things started timing out. Since I use the Slashdotter extension for Firefox, I immediately clicked on all the.nyud.net:8090 copies of the links. Some of them are still trying to get cached, but here's the complete list of the mentioned links.
Indentation preferences vary among programmers, are arbitrary, and some people feel strongly about 4-space, 2 space, tabs, etc. Python uses this as a syntax element and forces everyone working on a particular file to share the same indentation scheme or risk breaking the code. Some of use view this as a good thing.;-)
Personally, I hate tabs. Every editor I use seems to have the tab-stops set differently, and looking at 4-space tab code in an 8-space tab editor is not my idea of fun.
The parent post will get a lot of mods as "Funny" but there's a serious point behind it. After many years in the tech business, I've decided that the most valuable skill is salesmanship. I mean this in a generic way, of course. As an employee you have to sell yourself to your boss to get a raise, while as a consultant you have to sell yourself to your clients to get a contract. Heck, as a grad student you have to sell your ideas to your faculty advisors. Now, I don't mean a used-car salesman whom you probably never see again after you close the deal, I mean the long-term relationship type of salesman employed by tech vendors. Yeah, that's right, the types of salesmen who spend their days playing golf with their customers.
So, my advice is to go the the library and read one of these books:
Or if your library doesn't have these, follow the links to Amazon, find some similar books, and look for them at the library. The principles can be applied everywhere; they will make a real difference in your life.
I don't know anyone who uses port knocking to connect to an unencrypted channel. http://www.portknocking.org/ says, "There will be situations in which port knocking is ideally suitable, such as remote administration provided by a latent, on-demand SSH service. In other cases port knocking is not the right answer." So, I don't see a replay attack as being that likely.
As I said in my top post, I like the article's idea, just not the implementation. For instance, use 1,000 ports and change the three-knock code every five seconds. If you allow any of the last twenty patterns to succeed then the odds of a successful attack drop to 20-in-1,000,000,000. If you really like authpf, then go ahead and connect to authpf once you get through. Even then, you should still restrict the user to an SSH channel. Layered security is good.
Slashdot Mirror
2) Build a lunar mass driver to launch bricks and I-beams (plus other infrastructure items) to Mars.
3) Build a Mars base, modeled after Biosphere One. Operate it for at least one Martian year without humans.
4) Send 12-25 people, aged 65+, with enough supplies to spend the rest of their lives on Mars. (Not having to return will drasticly reduce the mission cost.)
5) ??? (Evalute feasibility of sending younger colonists.)
6) Profit!!!
Note that this plan will require no human space flight beyond low Earth orbit prior to step 4. It should be possible to reach step 4 within twenty years of implementation.
Lots of reputable physicists have speculated that the fundamental physical constants have varied over the life of the Universe, although those theories do tend to get knocked down pretty quickly. See http://en.wikipedia.org/wiki/Variable_speed_of_light for an overview.
On a related note, http://en.wikipedia.org/wiki/Big_Rip speculates that gravity may not work at distances over 46.5e9 light years, and that that distance is decreasing over time. If true, then eventually "all hell breaks loose".
Go ahead and learn the 2.x version. The 3.0 version isn't much different, and the differences are usually trivial. For example, any time there are two version of a function in 2.x, one of which starts with an 'x', it's almost always the 'x' version that you want to use. So go ahead and do so; all that happens in 3.0 is that the 'x' will go away. The only other major change is that the print statement becomes a function, and the 2to3.py converter will handle that conversion just fine.
One word: Pixar
I totally agree. http://www.penny-arcade.com/comic/2007/12/03
You obviously never watched it in a theater. If you ate your brownies as the movie started, then you were set for the psychedelia at the end.
Change IE8 to use this user-agent string:
Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.11) Gecko/20071127 Firefox/2.0.0.4
My understanding is that even that is hard. A modern A-bomb consists of a spherical shell of uranium with multiple explosive charges surrounding it. When the charges are set off, they crumple the shell into a solid sphere and it goes BOOM. Due to (probably intentional) variances in the manufacturing process, the charges can't be detonated at the same time, but must be set off in a special order with delays of several milliseconds. Cleverly, the firing code used to detonate is the list of these delays; the only way to determine the validity of a code is to try using it and see if you get a BOOM or a fizzle (i.e., everything melts and you're left with a puddle of molten uranium/iron alloy). Which means that if you ever manage to steal a bomb, your best bet is to disassemble it and recast the uranium into two half-spheres which you then slap together at high speed.
I frequently lay my cellphone next to my keyboard. Then, when I want to use the mouse, I'll accidentally grab the phone instead. After wasting a few cycles wondering why the cursor isn't responding, I look at my hand, place the cell phone a bit father from the keyboard, and grab the real mouse. It's only embarrassing if someone is looking over my shoulder.
The biggest industrial process will involve the casting of paving stones and Lego-like components from molten rock. The only limiting factor for self-replication is chlorine, which is needed to refine aluminum from lunar materials. The other elements that you mention may not be plentiful in any absolute sense, but they are plentiful enough. For example, Helium-3 is present at concentrations on the order of 0.01 ppm, but there are serious proposals from China and Russia to mine that; by comparison, those other gases are easy to extract.
I'd hope to see the base OS support VM Player, which could boot (or restore) Windows in the background.
The paper goes into much detail, but little AI will be required. Most of the time, the machinery will require no more AI than an auto assembly line; when more intellegence is required, humans would teleoperate the equipment in much the same way that we currently control the Mars Exploration Rovers.
The initial seed factory was designed with two copies of everything vital, and will spend its first year building itself out before it attempts its first replication. Again, I point to the examples of Spirit and Opportunity, operating for four years now in a much harsher environment.
I'm not sure what your point is. The graph is from the paper I cited, and the authors go into some detail on how the various sub-processes will fit together. Yes, those "C"s, "F"s, "N"s, "P"s, and "H"s are only present in miniscule quantities on the moon, but a robotic manufacturing operation won't require large quantities of them to self-replicate. After a few years, you'll have dozens of self-repairing facilities operational, and then you'll shift to producing consumables for human tourists.
NASA has been looking into self-replicating lunar factories since at least 1980. http://www.islandone.org/MMSG/aasm/AASM53.html presents a proposal for a 100-ton "seed" factory that could replicate itself in one year, using 5-10 tons (per replica) of "vitamin" components supplied from Earth. (For comparison, the Apollo lunar lander delivered ~25 tons to the lunar surface.) We now know much more about the lunar surface, so some parts of the proposal need to be tweaked, but MIT has been running workshops on self-replicating equipment for the past several years; it should be possible to get such a factory built and delivered with minimal effort.
I'd use unionfs to mount a tmpfs on top of your SSD for log files and such. Have cron run snapmerge periodically to copy the changes back to the SSD. This will let your SSD enjoy a long and useful life. See http://www.linuxjournal.com/article/7714#N0xa50890.0xdfb370 for more info.
The key is the utility of the software, not its price. If something provides an advantage over their competition, your customer won't be inclined to give it away. In fact, most customers aren't interested in getting involved in the even minor requirements imposed by the GPL, i.e. making the source available to whomever they sell it to, so they won't be interested in distributing it at all; in their view, the cost of doing so exceeds the benefits. And don't forget that you've only sold the source to the company, not its employees. If someone uploads your code to Sourceforge, they're not only guilty of GPL violations, they've also stolen property from their employer.
Personally, I hate tabs. Every editor I use seems to have the tab-stops set differently, and looking at 4-space tab code in an 8-space tab editor is not my idea of fun.
So, my advice is to go the the library and read one of these books:
Or if your library doesn't have these, follow the links to Amazon, find some similar books, and look for them at the library. The principles can be applied everywhere; they will make a real difference in your life.
Are you sure it was some large corporation? It might have been the Office of Scientific Intelligence.
I don't know anyone who uses port knocking to connect to an unencrypted channel. http://www.portknocking.org/ says, "There will be situations in which port knocking is ideally suitable, such as remote administration provided by a latent, on-demand SSH service. In other cases port knocking is not the right answer." So, I don't see a replay attack as being that likely.
As I said in my top post, I like the article's idea, just not the implementation. For instance, use 1,000 ports and change the three-knock code every five seconds. If you allow any of the last twenty patterns to succeed then the odds of a successful attack drop to 20-in-1,000,000,000. If you really like authpf, then go ahead and connect to authpf once you get through. Even then, you should still restrict the user to an SSH channel. Layered security is good.