You haven't read his book. There are issues that are not addressed therein, and a few which are glossed over. However, all of the points you addressed are directly addressed in the book.
Lightweight low-power off-planet refining equipment has been "just on the horizon" for decades
Really? Please site. I would love to read about them.
Fact is there has never been a serious effort to build one, let along plans to actually need it. Americans can engineer anything, once we decide to do it. And automatic mining equipment really ins't that complex.
Also, Zubrin et al created a scale model of some of the oxygen mining gear. Worked great, needs to be tested.
. Mars eats probes (the "galactic ghoul"), and most of the failures couldn't have been prevented by humans being present
Apples to oranges comparison. And 100% WRONG. I honestly can't think of ONE of the missions which it could be claimed with any certainty would NOT have been saved without a human around to check things out. I can assure you that the massive 'units lesson' mission failure would have been caught well in advance with a human on board *even if nothing else were different*.
We're just starting to learn the properties of martian dust (if you'll recall, before Spirit and Opportunity experienced natural dust cleaning, it was expected that their panels would have caked over with dust long ago), which poses numerous potential hazards
Hazards? Like what? Are you claiming that humanity cannot overcome dust with static cling? For one thing, a person with a BROOM can take care of the solar panels, if said person is there. I'm not saying we should ignore the dust as if it isn't a potential source of difficulty; I am saying that it can be overcome.
I have yet to see a satisfying solution from any reputable source for dealing with bremsstrahlung radiation from galactic cosmic radiation (GCR) in transit
Worst case, we need to design a powerful magnetic field to surround the ship. So what?
lets not even get into how off-the-wall Zubrin's prices for "long-term colonization" transit to Mars are...
Zubrin's prices are spot on -- for the way he presents it. The way it will/would actually be handled by the US government would indeed make his price tag pitifully wrong.
Yes, we'll make it to Mars. But we're hardly "almost there", as Zubrin, and especially his devout followers, portray.
Nice ad hominum attack. Now, what is it that you have to gain by making it? Advancing your own ultra-negative, un-informed viewpoint? It is obvious that you haven't read Zubrin's book, and yet you comment on it as if you have. Your statements about spacecraft failure show that you are in possesion of limited knowledge of how those craft actually failed, and the differences in human rated and 'normal' spacecraft. You managed to avoid saying one positive thing in your entire post.
B) Mars's pressure is close enough to being a vaccuum: 0.007 atmospheres on average.
Thats a far cry from a vacuum. One percent of Earths own atmospheric pressure; equivilent to something like 35-40km altitude -- where planes fly.
Bulky pressure suits eh? You will have pressure suits if you need to leave in a hurry; but the pressure is high enough that low-pressure suits would be fine. Slightly more hinderance than cold weather gear -- actually, compared to cold weather gear of 50 years ago, far less bulky.
Got issues with a Mars program? Fine. You are free to voice them. But for gods sake, what the hell is the point of being so negative? You serve no one any benifit. Nevermind that you are also wrong on most counts, and that every single one of the issues you brought up are well known and even addressed in the very book you spite.
I would not have responded but for the significant annoyance brought on my the pointle
I've heard that theory before, but I was always under the impression that the 'accepted version' inolved that pesky asteroid strike which created Olympos Mons and the MASSIVE crater on the opposite side of the planet.
I suppose small chunks of the same rock could have come in moments later and had some nice happy aerobraking..
It is a fun problem: once you touch air, you are done without thrusters. There are no mechanisims which raise periapsis (generic term for perigee) fast enough to counter any significant resistence. But when a rock leaves from the surface of the planet, by definition if it is in 'orbit' then the orbital periapsis is going to be at the altitude from which it left -- e.g. THE GROUND. Hence there must be some complex interactions which occure at high altitude in order to but a rock into a 'real' orbit. However, I am certain that when you blast a trillion trillion tonnes of rock from the face of a planetary body, a few of the pieces will off-gas enough, explode, or just bounce of other pieces enough to obtain a longer-term stable orbit (days weeks, who knows? Maybe even eons). OR you can blast a bunch of rock into a trailing orbit -- it reaches escape velocity from Mars, and continues to orbit in the same heliocentric orbit, trailing or leading Mars by a bit, and slightly more elliptical. Their paths would cross once in a while for sure -- which could lead to a later recapture: see the part about super-nice velocity matching below.
The allowable mechanisms for an asteriod to be captured are much lower --- if it hits the atmosphere, that becomes its lowest point. Period. So it will continue to hit the atmosphere time and time again.
If asteriod is going so fast that the atmosphere heats it up enough to do anything, chances are it is going way to fast to be captured. If said asteriod is going so slow that it can be captured without aero braking --- well, lets just say that ANYTHING is possible in these timeframes, but I would never play a lottery with odds like that... unless we are talking about rocks that left Mars in the past and are in the same orbit as Mars is with respect to the sun.
Phobos is orbiting at about 2km/sec around Mars, Deimos at about 1.36 -- in just about the most perfectly circular orbits you ever could imagine (e = 0.001 and 0.00 respectively). Which means that these suckers were moving at almost exactly whatever speed the are going now when they were captured.
...until proven otherwise, it might actually be true that physically smaller races have slightly lower average intelligence. Has it been proven otherwise
Actually, I think the answer is yes. Intelligence of animals has been found to relate to the brain-size to body mass ratio.
As to dismissing scientific results on the grounds of 'sounds like BS' -- well, you are kinda right, it should not be done... unless you are reading the ACTUAL research paper, and not some science writers interpretation thereof.
Thats great. Not the point of the argument though -- honestly, I could give a crap who uses what keyboard. There is no layout that is really great, certainly not one that makes it worth dealing with using a non-standard layout. One day a completely novel form of 'puter input will arrive and the point will be moot. Fairly soon, I believe. Fact of the matter is, lying a bunch of buttons flat on a desk in a generally fixed position is going to cause stress on whomever needs to use it 8 hours a day -- or more. You a heavy computer user? Go get a professional massage -- promise you won't need to tell the masseuse what you do all day.
But I digress. The one and only point I was trying to make is that there are a bunch of asshats out there spreading BS about the QWERTY layout and how it was designed to be slow. Some of those doing it are just honestly spreading 'what they heard'. Others are too f*ing stupid to be bothered with thinking and refuse to pay attention to the many links on google and, hell, for that matter just considering for a moment how the damned keyboard is layed out and how a mechanical keyboard works.
As to having all those nifty words in the home row? So what? Can you PROVE to me, with well done research, that having words in the home row actually makes typing them faster? Maybe -- this is just a curve ball I'll throw out -- maybe having letters in off rows makes typing faster? Certainly I believe that having the most commen two letter combos alternate hands would be faster -- one hand can be preparing to 'fire' while the other is busy pushing a button.
Furthermore, the number of WORDS that can be typed by letters in the home row is a non-sequitor -- it has no meaning in this context or any other. *None* What you are looking for is frequency of use of each letter. What's more, you want to see the hands returning to the home row at the end of most words, and most words beginning with letters that start on the home row. Which aoeuhtns fails COMPLETELY at. Why? Simple logic -- where are your hands supposed to go when you don't know what to type next? The home row. Once the mechanical action of typing has begun, muscle memory takes over and where the key is on the keyboard -- provided it is not physically difficult to reach -- matters not much at all -- provided that key isn't one that uses the same finger as the previous key -- e.g. putting 'q' and 'u' in the same column would be stupid, Etc.
Fact of the matter is that neither DVORAK nor QWERTY were created out of well done, long term time-and-motion studies. One was slapped together by a fairly brilliant man, the other slapped together by a man who tried to make the world think that he was smarter so he could earn money ripping off the government. Personally, I'll take the former, which means QWERTY.
Get back to me when we have a REAL alternative - one that doesn't involve having my arms sticking out in front of me in one position all day long.
Re:So.... who wants to tell him?
on
Advocating Dvorak
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· Score: 3, Informative
Dear god. Okay, step by step.
1.) The keys didn't jam because of speed. They jammed because they were CLOSE to one another physically; the impact head on the typewriter was related in position to the location of the key on the keyboard. Simple mechanics.
2.)By putting two letters that are often side by side (e.g. si, ti, to,an, qu, th, etc) on opposing sides of the keyboard you also made it such that the impact heads would be 'coming in' from the left and right sides, and not both from the left side or both from the right.
By doing this you prevented, in most case, two letters trying to be in the same place at the same time -- which almost invariably caused a jam on the lever-arm type-writers. And yes, I've used one.
This does not mean the keyboard was meant to slow you down. It wasn't. I was used to speed up typing.
So, please, kill the keyboard FUD and just use whatever you bloody want to.
In 100% seriousness, I think you should talk with someone about your own self image. Be it your own family, your mom, a sister or close aunt, or a counselor.
If you truly are as scared/upset/bitter/pissed as your letter makes it sound, then it needs to end. Not the relationship -- perhaps -- but the conditions that make it so scary. The way in which you phrased your letter made it sound like 'he sucks, but I certainly couldn't do better'; which is *never* true: if you are afraid of being tossed aside one day because Father Time has finally caught up with you then you can certainly do better.
It could be as simple as a communication problem -- I'm not there, I don't know.
Sounds like it belongs in an addon then. Not in a generic environment. Video, sound and 3D vector ops have very little in commen with, say, SQL queries.
0x86 chips have added silicon AFTER, not BEFORE Microsoft created all of their sound and video extensions. Unlike the implication of GP. And MMX was a response to the fact that 'omg! People use video and sound!'. Linux and anyone else is free to take advantage of the extra instructions, and is the case with Linux at least.
If Cell doesn't have special instructions for doing quaternion rotations then I don't give a crap how fast it is: an Intel/AMD/0x86 chip will walk all over it in video operations.
And even if Cell does... can that make it a great generic OS processor? Nope! Takes a lot more than that!
As in everything, time will tell. I certainly do hope that it is a revolution; I foresee living through very few GOOD revolutions during my lifetime. The more the merrier.
What I want to know is "Does this 'uber-multiprocessor ready' architecture have some kind of 'priority' flag that one uses on a thread?
More succinctly: how does it handle its passing of processing requests to other 'cells'?
Using some (tiny, tiny bits of) ASM, I started to wonder about this. I mean, dear GOD! How do you deal with it? Some form of modified call I would suppose, like:
And when the result comes in it fires some interupt. Maybe that would be specified in the ASM instruction?
Obviously the compiler would have to know when to use the 'external call allowed' ASM command, hence my mention of a priority flag (e.g. 'need this NOW!!!' vs 'hey.. whenever')
Being fully underwater is at least a factor of 5 more efficient than being on the surface.
Its all about breaking the surface tension.
b.) negates a.), and isn't an issue; the few pounds that would be required could easily be streamlined, and would be but a tiny tiny issue compared to the drysuit/6mm wetsuit you'd have to wear to avoid dying of hypothermia.
Your peripheral vision can detect changes at speeds significantly higher than your main vision. Hence why if you stare straight at a CRT monitor with 60Hz refresh, you can't really notice a flicker... but if you focus 20 degrees to either side of the monitor and 'peek' out of the corner of your eye, you will easily notice the missing information.
Also, 60Hz refresh -- even on LCDs, which maintain an image far longer than a CRT -- sometimes causes horrible headaches when combined with cheap (electronic ballast, rather than the old school inductor based ballast) fluorescent lighting. At least in countries that use 60Hz AC power.
It is not the solar wind that is captured by solar sails... it is sunlight.
Moments after I posted that I wanted to kick myself. I do recall that some portion of your acceleration comes from the solar wind as well; less than a few percent though.
As to most of the rest, I was just really don't like seeing massively incorrect posts marked as '+5, Informative'. I am a big fan of solar sails, and think they have a strong future. I like mag-sails MORE, as they are easier to control (turn on and off, no stowing of flimsy material). But we can build massive solar sails NOW if we really wanted to, whereas we still have some development to do to get high-amp capability in high-temperature superconductors.
The laser thing is fun, but I can't believe it will ever happen. Why? Because to power a laser that potent you would need a fusion reactor that can generate probably tens of times the energy that you put into the laser itself. Dump that same reactor on the ship itself and you can get a specific impulse of something like 2 million seconds. Todays best propulsion gives about 480 seconds.
What that means in english (well, metric) is that for every kilogram of fuel you put in per second, you get (2 million * 9.806) newtons of thrust for 1 second. (F = Isp * mass/sec * gravity at sea level). So for 1kg of fuel you burn per second you get about 20 million newtons of force for that second.
A better way to think about specific impulse is that Isp represnts the number of kilograms of mass you can accelerate at 1 gravity of acceleration. A specific impulse of 500 seconds, in space, would accelerate 500kg of mass at a rate of 9.806m/s^2. This ONLY works if you assume a burn rate of 1kg per second.
So an Isp of 2E6 seconds lets you accelerate 2E6 kg of ship at one gravity, assuming a burn rate of 1kg per second.
In reality, you won't be seeing a burn rate of 1kg per second for any fusion reactor, but the rest of the math is real. You would just accelerate more slowly over a longer period of time.
Since fusion of He3 + Deterium is about 1% efficient (? memory, could have wrong path), 1kg/sec of fuel burn would mean: E = m*c^2 = 1_kg/s * c^2 * 1% = 8.99E14J/s = 899TW.
Oh yes! You are correct. I am very sorry if I sound like I am against solar sails!
My arguement was actually rather inelegant in the regard that I certainly sounded like I was arguing against sails.
For reference, I prefer the concept of mag-loops; but regarding sails:
1.) Larger sails: Yes, we would use larger sails. But the force supplied only rises with direct proportion to the sail area. And it adds weight in tie-lines etc.
2.) I only used mars as a reference. The use of a sail is indeed ideal for deep space missions. And ONLY for deep space missions, in my mind, in the 'near term'. In the long term, sails would be very nice for cyclic missions to mars, using 'free return' trajectories. A sail would allow for slowing the craft down some for 'catching it' at either end of the cycle, and speed it back up afterwords. It wouldn't be a true free return orbit at that point, but you get the idea. FAR future, for non-person cargo transportation.
What I wanted to get across is that solar sails are SLOW. If you want to use them to get anywhere, you are still going to boost them out of Earths orbit and probably towards a flyby with Mercury. Mercury being at 0.387AU from the sun, you get 6.67 times the force on the sail area as you do at Earths orbit (F is proportional to 1/R^2, 1/0.387^2 = 6.67).
You also get the bonus of a Mercury flyby. On the way back 'up' you can loop by venus, then earth, then mars gaining a few km/s depending on which of them you fly by and how many times. Stow the sail on the way back down towards the sun, and pull it out again at perihelion and start the process all over again.
Do this three or four times and you will be hauling ass on your way out of the solar system.
Second reply to this post. I did some math, to show how naive the parent post is:
Assume 10Kg craft.
F = (S*A*sin(theta) / c
Theta = incident angle A = area S = solar flux
Let theta = 0, A = 100m^2, S = 1.36KW/m^2
F = 0.000454 N
a = F/m =.000454N/(10kg) = 0.000045365 _m/_s^2
22043.6 Seconds to reach 1 meter per second (6.12 hours)
So about 6 hr/(m/s)*4500(m/s)(about that needed to get to mars on a nice, almost hohmann, orbit from earth orbit). = 1125 days.
Presently we can get to mars in about 180 days.
V_esc for sun at earths orbit: M_sol = 2E30 kg, R_eo = 1_Au = 1.496E8 km G = gravitational constant = 6.6726E-11m^3/(kg*s^2) V_esc = root(2G*M/R) = root(2*G*M_sol/R_eo) = 42.239 km/s
Add to that the velocity to seperate the crafts orbit from earths: ~3km/s = ~45km/s
Using a straight shot, which is completely 100% impossible, it would take 6.12hrs/(m/s) * 45000 m/s = 31 years, 315 days. Even.
The reason a straight shot wouldn't work is that flux falls off as the square of distance. So you would need to integrate over time to obtain your velocity, with an inner equation dependant position, which is dependant on your velocity, which is dependant on your past acceleration, which is dependant on your past position... you get the idea.
22043.6 Seconds to reach 1 meter per second (6.12 hours)
So about 6 hr/(m/s)*4500(m/s)(about that needed to get to mars on a nice, almost hohmann, orbit from earth orbit). = 1125 days.
Presently we can get to mars in about 180 days.
So, yes. Over a *LOOOOONNNG* time.
I believe that one must achieve about 44km/sec delta V from earth to escape the solar system. That is almost a guess it is so tenuous a memory. Maybe that is Voyagers velocity relative to the sun.
I don't have time to run through the math, but your value for S is squared every time you cut the distance between your sail and the sun is cut in half. Add to that the velocity gain you can get via gravity assist around mercury, venus mars and earth, and you can achieve real velocities fairly quickly.
But you still use a booster to get on the initial orbit, or you will be waiting forever.
You could also use solar sails for other stationkeeping like the L1,L2, & L3 Lagrange points which is needed for certain telescopes.
For those who don't know, L1 -L3 are the quasi-stable lagrange points.
(L4 and L5 are far more stable)
I believe the quote is 'It's a great idea.... it just won't work'. If you have ever seen an orbit of an L(1-3) point you would know why. *shudder*. The dynamics involved are pretty short term; which is to say, the tiny tiny tiny amounts of thrust you would get from a solar sail won't help you much. And the speed at which you would need to be able to re-orient the sail would be very high; high to the point of making the vehicle to which it was attached useless for pretty much any kind of space science (as it would be wobbling all over the place).
The point of the solar sail is that it will be able to attain a much higher velocity then voyager due to the constant acceleration of the sail.
MicroNewtons of force does not equate to much acceleration.
You still have to do flybys if you want to get anywhere within a human lifetime. Plus, by going near the sun, you achieve much much higher acceleration on the outward legs. So long as you don't melt your sail;~)
This does require a storable/deployable sail for highest efficiency.
No. It can't: for one thing, the solar wind is *NOT* moving at the speed of light.
For another, it would take YEARS or to accelerate to any significant velocity... like even a tenth of a percent of C (which is still hauling ass).
Off the top of my head I recall seeing a decade brandied about. That would be via a number of trips into the inner solar system. Why inner? Because the solar flux is far more dense, and your acceleration higher (flux drops off with the square of distance; thus thrust decreases with the square of distance.
By dipping into the inner system you can also do a number of flybys of Venus, Earth, Mars and eventually jupiter and saturn. Thus you leave the solar system in 10 to 20 years, depending on the number of flybys and what direction you wish to go, moving at MOST a 1/2 a percent of light speed.
If you want to go much faster, you would have to do a nice, tight 'kiss the sun' flyby of our dear Sol. We don't have the materials that could survive this.
Slashdot Mirror
You haven't read his book. There are issues that are not addressed therein, and a few which are glossed over. However, all of the points you addressed are directly addressed in the book.
Lightweight low-power off-planet refining equipment has been "just on the horizon" for decades
Really? Please site. I would love to read about them.
Fact is there has never been a serious effort to build one, let along plans to actually need it. Americans can engineer anything, once we decide to do it. And automatic mining equipment really ins't that complex.
Also, Zubrin et al created a scale model of some of the oxygen mining gear. Worked great, needs to be tested.
. Mars eats probes (the "galactic ghoul"), and most of the failures couldn't have been prevented by humans being present
Apples to oranges comparison. And 100% WRONG. I honestly can't think of ONE of the missions which it could be claimed with any certainty would NOT have been saved without a human around to check things out. I can assure you that the massive 'units lesson' mission failure would have been caught well in advance with a human on board *even if nothing else were different*.
We're just starting to learn the properties of martian dust (if you'll recall, before Spirit and Opportunity experienced natural dust cleaning, it was expected that their panels would have caked over with dust long ago), which poses numerous potential hazards
Hazards? Like what? Are you claiming that humanity cannot overcome dust with static cling? For one thing, a person with a BROOM can take care of the solar panels, if said person is there. I'm not saying we should ignore the dust as if it isn't a potential source of difficulty; I am saying that it can be overcome.
I have yet to see a satisfying solution from any reputable source for dealing with bremsstrahlung radiation from galactic cosmic radiation (GCR) in transit
Chapter 5: Killing Dragons, Avoiding Sirens. Page 113. Covers the radiaton issue lightly.
Worst case, we need to design a powerful magnetic field to surround the ship. So what?
lets not even get into how off-the-wall Zubrin's prices for "long-term colonization" transit to Mars are...
Zubrin's prices are spot on -- for the way he presents it. The way it will/would actually be handled by the US government would indeed make his price tag pitifully wrong.
Yes, we'll make it to Mars. But we're hardly "almost there", as Zubrin, and especially his devout followers, portray.
Nice ad hominum attack. Now, what is it that you have to gain by making it? Advancing your own ultra-negative, un-informed viewpoint? It is obvious that you haven't read Zubrin's book, and yet you comment on it as if you have. Your statements about spacecraft failure show that you are in possesion of limited knowledge of how those craft actually failed, and the differences in human rated and 'normal' spacecraft. You managed to avoid saying one positive thing in your entire post.
B) Mars's pressure is close enough to being a vaccuum: 0.007 atmospheres on average.
Thats a far cry from a vacuum. One percent of Earths own atmospheric pressure; equivilent to something like 35-40km altitude -- where planes fly.
Bulky pressure suits eh? You will have pressure suits if you need to leave in a hurry; but the pressure is high enough that low-pressure suits would be fine. Slightly more hinderance than cold weather gear -- actually, compared to cold weather gear of 50 years ago, far less bulky.
Got issues with a Mars program? Fine. You are free to voice them. But for gods sake, what the hell is the point of being so negative? You serve no one any benifit. Nevermind that you are also wrong on most counts, and that every single one of the issues you brought up are well known and even addressed in the very book you spite.
I would not have responded but for the significant annoyance brought on my the pointle
I've heard that theory before, but I was always under the impression that the 'accepted version' inolved that pesky asteroid strike which created Olympos Mons and the MASSIVE crater on the opposite side of the planet.
I suppose small chunks of the same rock could have come in moments later and had some nice happy aerobraking..
It is a fun problem: once you touch air, you are done without thrusters. There are no mechanisims which raise periapsis (generic term for perigee) fast enough to counter any significant resistence. But when a rock leaves from the surface of the planet, by definition if it is in 'orbit' then the orbital periapsis is going to be at the altitude from which it left -- e.g. THE GROUND. Hence there must be some complex interactions which occure at high altitude in order to but a rock into a 'real' orbit. However, I am certain that when you blast a trillion trillion tonnes of rock from the face of a planetary body, a few of the pieces will off-gas enough, explode, or just bounce of other pieces enough to obtain a longer-term stable orbit (days weeks, who knows? Maybe even eons). OR you can blast a bunch of rock into a trailing orbit -- it reaches escape velocity from Mars, and continues to orbit in the same heliocentric orbit, trailing or leading Mars by a bit, and slightly more elliptical. Their paths would cross once in a while for sure -- which could lead to a later recapture: see the part about super-nice velocity matching below.
The allowable mechanisms for an asteriod to be captured are much lower --- if it hits the atmosphere, that becomes its lowest point. Period. So it will continue to hit the atmosphere time and time again.
If asteriod is going so fast that the atmosphere heats it up enough to do anything, chances are it is going way to fast to be captured. If said asteriod is going so slow that it can be captured without aero braking --- well, lets just say that ANYTHING is possible in these timeframes, but I would never play a lottery with odds like that... unless we are talking about rocks that left Mars in the past and are in the same orbit as Mars is with respect to the sun.
Phobos is orbiting at about 2km/sec around Mars, Deimos at about 1.36 -- in just about the most perfectly circular orbits you ever could imagine (e = 0.001 and 0.00 respectively). Which means that these suckers were moving at almost exactly whatever speed the are going now when they were captured.
...until proven otherwise, it might actually be true that physically smaller races have slightly lower average intelligence. Has it been proven otherwise
Actually, I think the answer is yes. Intelligence of animals has been found to relate to the brain-size to body mass ratio.
As to dismissing scientific results on the grounds of 'sounds like BS' -- well, you are kinda right, it should not be done... unless you are reading the ACTUAL research paper, and not some science writers interpretation thereof.
Thats great. Not the point of the argument though -- honestly, I could give a crap who uses what keyboard. There is no layout that is really great, certainly not one that makes it worth dealing with using a non-standard layout. One day a completely novel form of 'puter input will arrive and the point will be moot. Fairly soon, I believe. Fact of the matter is, lying a bunch of buttons flat on a desk in a generally fixed position is going to cause stress on whomever needs to use it 8 hours a day -- or more. You a heavy computer user? Go get a professional massage -- promise you won't need to tell the masseuse what you do all day.
But I digress. The one and only point I was trying to make is that there are a bunch of asshats out there spreading BS about the QWERTY layout and how it was designed to be slow. Some of those doing it are just honestly spreading 'what they heard'. Others are too f*ing stupid to be bothered with thinking and refuse to pay attention to the many links on google and, hell, for that matter just considering for a moment how the damned keyboard is layed out and how a mechanical keyboard works.
As to having all those nifty words in the home row? So what? Can you PROVE to me, with well done research, that having words in the home row actually makes typing them faster? Maybe -- this is just a curve ball I'll throw out -- maybe having letters in off rows makes typing faster? Certainly I believe that having the most commen two letter combos alternate hands would be faster -- one hand can be preparing to 'fire' while the other is busy pushing a button.
Furthermore, the number of WORDS that can be typed by letters in the home row is a non-sequitor -- it has no meaning in this context or any other. *None*
What you are looking for is frequency of use of each letter. What's more, you want to see the hands returning to the home row at the end of most words, and most words beginning with letters that start on the home row. Which aoeuhtns fails COMPLETELY at. Why? Simple logic -- where are your hands supposed to go when you don't know what to type next? The home row. Once the mechanical action of typing has begun, muscle memory takes over and where the key is on the keyboard -- provided it is not physically difficult to reach -- matters not much at all -- provided that key isn't one that uses the same finger as the previous key -- e.g. putting 'q' and 'u' in the same column would be stupid, Etc.
Fact of the matter is that neither DVORAK nor QWERTY were created out of well done, long term time-and-motion studies. One was slapped together by a fairly brilliant man, the other slapped together by a man who tried to make the world think that he was smarter so he could earn money ripping off the government. Personally, I'll take the former, which means QWERTY.
Get back to me when we have a REAL alternative - one that doesn't involve having my arms sticking out in front of me in one position all day long.
Dear god. Okay, step by step.
1.) The keys didn't jam because of speed. They jammed because they were CLOSE to one another physically; the impact head on the typewriter was related in position to the location of the key on the keyboard. Simple mechanics.
2.)By putting two letters that are often side by side (e.g. si, ti, to,an, qu, th, etc) on opposing sides of the keyboard you also made it such that the impact heads would be 'coming in' from the left and right sides, and not both from the left side or both from the right.
By doing this you prevented, in most case, two letters trying to be in the same place at the same time -- which almost invariably caused a jam on the lever-arm type-writers. And yes, I've used one.
This does not mean the keyboard was meant to slow you down. It wasn't. I was used to speed up typing.
So, please, kill the keyboard FUD and just use whatever you bloody want to.
Thanks :~)
And I love your tag.
In 100% seriousness, I think you should talk with someone about your own self image. Be it your own family, your mom, a sister or close aunt, or a counselor.
If you truly are as scared/upset/bitter/pissed as your letter makes it sound, then it needs to end. Not the relationship -- perhaps -- but the conditions that make it so scary. The way in which you phrased your letter made it sound like 'he sucks, but I certainly couldn't do better'; which is *never* true: if you are afraid of being tossed aside one day because Father Time has finally caught up with you then you can certainly do better.
It could be as simple as a communication problem -- I'm not there, I don't know.
Or it could mean that Longhorn will need to simulate XP in order to be backwards compatible....
Remember how win95 wasn't really using DOS? Really.. it wasn't. Nooooooo. Of course not.
I looked. But I admit I was a bit tipsy.
Wait....
Seriously though, do tell. The link in the body really didn't say much, despite the significant number of words.
Drawing up plans for that business sounds about as smart as starting a power trading company and recording all your phone calls... um.....
;~)
But it does sound lucrative
except no ASM code uses C function notation [e.g. func(x)] ;~)
;~)
But yes. Funny haha
Sounds like it belongs in an addon then. Not in a generic environment. Video, sound and 3D vector ops have very little in commen with, say, SQL queries.
0x86 chips have added silicon AFTER, not BEFORE Microsoft created all of their sound and video extensions. Unlike the implication of GP. And MMX was a response to the fact that 'omg! People use video and sound!'. Linux and anyone else is free to take advantage of the extra instructions, and is the case with Linux at least.
If Cell doesn't have special instructions for doing quaternion rotations then I don't give a crap how fast it is: an Intel/AMD/0x86 chip will walk all over it in video operations.
And even if Cell does... can that make it a great generic OS processor? Nope! Takes a lot more than that!
As in everything, time will tell. I certainly do hope that it is a revolution; I foresee living through very few GOOD revolutions during my lifetime. The more the merrier.
What I want to know is "Does this 'uber-multiprocessor ready' architecture have some kind of 'priority' flag that one uses on a thread?
More succinctly: how does it handle its passing of processing requests to other 'cells'?
Using some (tiny, tiny bits of) ASM, I started to wonder about this. I mean, dear GOD! How do you deal with it? Some form of modified call I would suppose, like:
call_avail mem_Address_Of_Function, MemAddress_To_Store_Result
And when the result comes in it fires some interupt. Maybe that would be specified in the ASM instruction?
Obviously the compiler would have to know when to use the 'external call allowed' ASM command, hence my mention of a priority flag (e.g. 'need this NOW!!!' vs 'hey.. whenever')
Anyone know and care to explain?
cheers,
With Linux, this has been pushed into the anals of history
An interesting choice of typos. Unintentional (I presume) and yet....
Um. Ever watched olympic swimming?
Being fully underwater is at least a factor of 5 more efficient than being on the surface.
Its all about breaking the surface tension.
b.) negates a.), and isn't an issue; the few pounds that would be required could easily be streamlined, and would be but a tiny tiny issue compared to the drysuit/6mm wetsuit you'd have to wear to avoid dying of hypothermia.
Your peripheral vision can detect changes at speeds significantly higher than your main vision. Hence why if you stare straight at a CRT monitor with 60Hz refresh, you can't really notice a flicker... but if you focus 20 degrees to either side of the monitor and 'peek' out of the corner of your eye, you will easily notice the missing information.
Also, 60Hz refresh -- even on LCDs, which maintain an image far longer than a CRT -- sometimes causes horrible headaches when combined with cheap (electronic ballast, rather than the old school inductor based ballast) fluorescent lighting. At least in countries that use 60Hz AC power.
It is not the solar wind that is captured by solar sails... it is sunlight.
;~)
Moments after I posted that I wanted to kick myself. I do recall that some portion of your acceleration comes from the solar wind as well; less than a few percent though.
As to most of the rest, I was just really don't like seeing massively incorrect posts marked as '+5, Informative'. I am a big fan of solar sails, and think they have a strong future. I like mag-sails MORE, as they are easier to control (turn on and off, no stowing of flimsy material). But we can build massive solar sails NOW if we really wanted to, whereas we still have some development to do to get high-amp capability in high-temperature superconductors.
The laser thing is fun, but I can't believe it will ever happen. Why? Because to power a laser that potent you would need a fusion reactor that can generate probably tens of times the energy that you put into the laser itself. Dump that same reactor on the ship itself and you can get a specific impulse of something like 2 million seconds. Todays best propulsion gives about 480 seconds.
What that means in english (well, metric) is that for every kilogram of fuel you put in per second, you get (2 million * 9.806) newtons of thrust for 1 second. (F = Isp * mass/sec * gravity at sea level). So for 1kg of fuel you burn per second you get about 20 million newtons of force for that second.
A better way to think about specific impulse is that Isp represnts the number of kilograms of mass you can accelerate at 1 gravity of acceleration. A specific impulse of 500 seconds, in space, would accelerate 500kg of mass at a rate of 9.806m/s^2. This ONLY works if you assume a burn rate of 1kg per second.
So an Isp of 2E6 seconds lets you accelerate 2E6 kg of ship at one gravity, assuming a burn rate of 1kg per second.
In reality, you won't be seeing a burn rate of 1kg per second for any fusion reactor, but the rest of the math is real. You would just accelerate more slowly over a longer period of time.
Since fusion of He3 + Deterium is about 1% efficient (? memory, could have wrong path), 1kg/sec of fuel burn would mean:
E = m*c^2 = 1_kg/s * c^2 * 1% = 8.99E14J/s = 899TW.
So, maybe we burn a gram per second
Oh yes! You are correct. I am very sorry if I sound like I am against solar sails!
My arguement was actually rather inelegant in the regard that I certainly sounded like I was arguing against sails.
For reference, I prefer the concept of mag-loops; but regarding sails:
1.) Larger sails: Yes, we would use larger sails. But the force supplied only rises with direct proportion to the sail area. And it adds weight in tie-lines etc.
2.) I only used mars as a reference. The use of a sail is indeed ideal for deep space missions. And ONLY for deep space missions, in my mind, in the 'near term'. In the long term, sails would be very nice for cyclic missions to mars, using 'free return' trajectories. A sail would allow for slowing the craft down some for 'catching it' at either end of the cycle, and speed it back up afterwords. It wouldn't be a true free return orbit at that point, but you get the idea. FAR future, for non-person cargo transportation.
What I wanted to get across is that solar sails are SLOW. If you want to use them to get anywhere, you are still going to boost them out of Earths orbit and probably towards a flyby with Mercury. Mercury being at 0.387AU from the sun, you get 6.67 times the force on the sail area as you do at Earths orbit (F is proportional to 1/R^2, 1/0.387^2 = 6.67).
You also get the bonus of a Mercury flyby. On the way back 'up' you can loop by venus, then earth, then mars gaining a few km/s depending on which of them you fly by and how many times. Stow the sail on the way back down towards the sun, and pull it out again at perihelion and start the process all over again.
Do this three or four times and you will be hauling ass on your way out of the solar system.
dependent. Not dependant. sheesh. like 5 times too.
Second reply to this post. I did some math, to show how naive the parent post is:
.000454N/(10kg) = 0.000045365 _m/_s^2
Assume 10Kg craft.
F = (S*A*sin(theta) / c
Theta = incident angle
A = area
S = solar flux
Let theta = 0, A = 100m^2, S = 1.36KW/m^2
F = 0.000454 N
a = F/m =
22043.6 Seconds to reach 1 meter per second (6.12 hours)
So about 6 hr/(m/s)*4500(m/s)(about that needed to get to mars on a nice, almost hohmann, orbit from earth orbit). = 1125 days.
Presently we can get to mars in about 180 days.
V_esc for sun at earths orbit:
M_sol = 2E30 kg,
R_eo = 1_Au = 1.496E8 km
G = gravitational constant = 6.6726E-11m^3/(kg*s^2)
V_esc = root(2G*M/R) = root(2*G*M_sol/R_eo) = 42.239 km/s
Add to that the velocity to seperate the crafts orbit from earths: ~3km/s = ~45km/s
Using a straight shot, which is completely 100% impossible, it would take 6.12hrs/(m/s) * 45000 m/s = 31 years, 315 days. Even.
The reason a straight shot wouldn't work is that flux falls off as the square of distance. So you would need to integrate over time to obtain your velocity, with an inner equation dependant position, which is dependant on your velocity, which is dependant on your past acceleration, which is dependant on your past position... you get the idea.
Assume 10Kg craft.
.000454N/(10kg) = 0.000045365 _m/_s^2
F = (S*A*sin(theta) / c
Theta = incident angle
A = area
S = solar flux
Let theta = 0, A = 100m^2, S = 1.36KW/m^2
F = 0.000454 N
a = F/m =
22043.6 Seconds to reach 1 meter per second (6.12 hours)
So about 6 hr/(m/s)*4500(m/s)(about that needed to get to mars on a nice, almost hohmann, orbit from earth orbit). = 1125 days.
Presently we can get to mars in about 180 days.
So, yes. Over a *LOOOOONNNG* time.
I believe that one must achieve about 44km/sec delta V from earth to escape the solar system. That is almost a guess it is so tenuous a memory. Maybe that is Voyagers velocity relative to the sun.
I don't have time to run through the math, but your value for S is squared every time you cut the distance between your sail and the sun is cut in half. Add to that the velocity gain you can get via gravity assist around mercury, venus mars and earth, and you can achieve real velocities fairly quickly.
But you still use a booster to get on the initial orbit, or you will be waiting forever.
You could also use solar sails for other stationkeeping like the L1,L2, & L3 Lagrange points which is needed for certain telescopes.
0 313202/103-2265602-2335000?v=glance). Including the station-keeping aspects, IIRC.
For those who don't know, L1 -L3 are the quasi-stable lagrange points.
(L4 and L5 are far more stable)
I believe the quote is 'It's a great idea.... it just won't work'. If you have ever seen an orbit of an L(1-3) point you would know why. *shudder*. The dynamics involved are pretty short term; which is to say, the tiny tiny tiny amounts of thrust you would get from a solar sail won't help you much. And the speed at which you would need to be able to re-orient the sail would be very high; high to the point of making the vehicle to which it was attached useless for pretty much any kind of space science (as it would be wobbling all over the place).
There are some good examples of uses for solar sails and super conducting magnetic loops in the last chapter of 'Space Propulsion Analysis and Design' (curtesy link: http://www.amazon.com/exec/obidos/tg/detail/-/007
The point of the solar sail is that it will be able to attain a much higher velocity then voyager due to the constant acceleration of the sail.
;~)
MicroNewtons of force does not equate to much acceleration.
You still have to do flybys if you want to get anywhere within a human lifetime. Plus, by going near the sun, you achieve much much higher acceleration on the outward legs. So long as you don't melt your sail
This does require a storable/deployable sail for highest efficiency.
AARGH!
No. It can't: for one thing, the solar wind is *NOT* moving at the speed of light.
For another, it would take YEARS or to accelerate to any significant velocity... like even a tenth of a percent of C (which is still hauling ass).
Off the top of my head I recall seeing a decade brandied about. That would be via a number of trips into the inner solar system. Why inner? Because the solar flux is far more dense, and your acceleration higher (flux drops off with the square of distance; thus thrust decreases with the square of distance.
By dipping into the inner system you can also do a number of flybys of Venus, Earth, Mars and eventually jupiter and saturn. Thus you leave the solar system in 10 to 20 years, depending on the number of flybys and what direction you wish to go, moving at MOST a 1/2 a percent of light speed.
If you want to go much faster, you would have to do a nice, tight 'kiss the sun' flyby of our dear Sol. We don't have the materials that could survive this.
And you can't sail into the wind with a sailing ship.
Oh. Wait......