It should have been a +5 Funny, right? At least I hope so...I thought he was joking, but I'm not so sure any more. The fact that he gets a +5 Insightful is scary. You crackhead moderators are also joking by modding it as Insightful, right? I'm used to idiotic posts (that's what the mod system is for), but if the moderators are just as crazy, the system breaks down.
I guess I did not make myself clear, judging by the number of posters trying to educate me on the relationship between energy, power, and time:-)
Yes, given a certain amount of energy, a pulsed laser is far more effective than a continuous one. An energy of 1 Joule in a nanosecond gives you a GigaWatt laser. The same energy in a millisecond only gives you a kiloWatt laser.
However, note that the article mentions that the power of the laser is 100 kW. It does not mention a fixed amount of energy.
Let me put it another way. Suppose we have two different lasers. Laser A has a power of 100kW, and delivers a 1 millisecond pulse, every second. Laser B also has 100kW of power, but delivers 1000 pulses of 1 millisecond, every second (so it's effectively a continuous laser). Which one is more effective? Laser A delivers 100J of energy every second. Laser B delivers 100,000J every second. (If you are going to argue now that laser A is a 100W laser, then I'm afraid I have confused you...).
Again, the fact that they need to dissipate 900kW, and use the fuel as a heat sink, leads me to believe that this is a (nearly) continuous laser. If it were using, say, a 1 millisecond pulse, they would need to dissipate 900J per pulse, which is not all that impressive.
Vent the steam. The F-35 is suppose to be stealthy. Leaving a con trail of vented steam does not help the stealth characteristics.
Furthermore, as an AC pointed out, these aerospace guys and completely and utterly paranoid about weight. I have worked on an aerospace program where a dual processor system was considered for the on-board computer. One of the arguments against the second processor was its weight (and the extra weigth to the power supply and heat sinks)! I don't blame you if you don't believe me, I could hardly believe it myself...
This is for a continuous wave laser (one that doesn't pulse). Now you can imagine what 100,000 watts will do:). The question is, seeing as how this must be firing in pulses, what is the pulse length? Minutes? Seconds? Milliseconds?
If the thing pulses, it only makes it less effective. Remember, it's 100,000 Watts, or 100,000 Joules per second. The longer the pulse (or continuous), the more energy it delivers. If it were to pulse for a microsecond, it would deliver 100 mJ per pulse, and that's not all that impressive. The fact that the dissipation of 900 kW poses some challenges leads me to believe that this thing is operating in (nearly) continuous mode. However, at the end of the day, the energy will have to come from the fuel, so there's a limitation there.
Far more significant is the diameter of the beam. This determines the amount of Watts per square meter. Lasers tend to have fairly narrow beams at the source, however, they also diverge a bit. At a distance of several kilometers this might be significant. Also, atmospheric diffraction could be a problem (possibly solved by the adaptive optics mentioned in the article).
But, given all this, I'm still puzzled. Say you could focus these 100kW in a narrow beam of for example 1 millimeter. This could probably burn a hole through a tank or an airplane. But what's the point of burning a 1 mm hole in a tank or plane? How much damage does that do? Alternatively, say the beam has a diameter of 1 meter. A one meter hole would probably do significant damage, especially to an airplane. However, that would amount to ~130kW per square meter, which is around 1000 times the intensity of the sun. That's about the same as using a (big) magnifying glass in sunny weather. How long would it take to burn a hole through anything? Especially tanks with their several feet of steel armor would survive this for quite some time, I would think.
Of course, it could be an anti-personnel weapon, but I have doubts on how effective this would be. What's the point of using an F-35 to pick off infantry troups one by one?
Numbskull moderator. Please mod parent up, it is not flamebait. The word "Nonsense" is actually from the SciAm article, it wasn't made up by the poster.
Natural selection picked out the chemical basis of genetic information transfer probably because it was the best of the available options for ensuring fidelity in reading and copying information.
Assuming that they mean "selection" as in an evolutionary sense, I fail to see how this can be true. Isn't the whole genetic chemistry (ATCG, DNA, etc.) necessary before any selection can take place at all? In other words, isn't this a chicken-and-egg problem? You need a self-replicating structure before you can have reproduction, which is necessary for selection (right?). Or are we to believe that there was once a whole slew of competing chemicals, and our good friends A,T, C, and G won the grand prize because they had a 'parity check'? But even if you buy into that, where did the repairing enzymes come from? Aren't enzymes encoded by... (drumroll...) DNA? I'm a bit out of my area of expertise here (I ain't no biochemist), but it does seem a bit strange to me...
Darn! At first I thought this had to be wrong, since Sunday is the day of rest, so that had to be the seventh day, not the first. Then I realized that the Sabbath is the seventh day, so this date must be right.
If the Universe is an ever expanding "sphere", then what is making it infinite?
Nothing. It's not infinite, it's finite. You are correct that the universe has an outer sphere, however, this is not a physical boundary, it's determined by the speed of light and the age of the universe. According to Einstein nothing can travel faster than the speed of light. So, if the universe is 16 billion years old, then the universe has a radius of 16 billion light years. So, nothing can pass through the border, since the border is defined by the fastest traveling thing (i.e. light).
IIRC there are observations or theories that the universe is slowing it's expansion due to the fact that matter attracts matter.
Actually, the lastest observations indicate that the expansion is speeding up rather than slowing down.
Besides that, it is clear that the matter in the universe is not expanding at the speed of light (gravity slows it down, and matter can't travel at light speed in the first place), so photons have overtaken the farthest matter already anyway. Again, the border of the universe is not determined by matter, but by photons.
In other news: not only did God decide to play a practical joke by burying fossils, He decided to bury them in order of complexity, i.e., the simpler the fossil, the deeper He buried it. A grinning God was quoted as saying: "If this doesn't make them believe in something silly like evolution, nothing will!".
Hmmm. According to The Nitpicker's Guide for Next Generation Trekkers by Phil Farrand (ISBN 1-85286-513-X, First Edition, 1993), Data still uses a contraction in Datalore: 'One of Data's last lines in this show is "I'm fine"...'. (page 36). Since I don't have a tape of every episode in a magnetically shielded vault, I can't verify this. Guess it's too much to hope that you could remember it...
...but with DVDs, you get a lot more for your money...
I disagree. Yes, you get a lot more additional material, that's all true, but how often do you play a particular DVD? Two, three times? And how often do you play a particular CD? 10, 20, 100 times? There's more hours of entertainment in a CD, in my opinion. Music can be played over and over again, at least more often than a movie. Also, CDs can be played while you're doing something else, this is a lot harder with a DVD.
To further my point, I've purchased far more DVDs than CDs in the last year, and it's not because I watch more movies than I listen to music...
Maybe it is because the 'replayability' of CDs is much better? See my previous argument.
Re:Interesting twisted misconceptions...
on
The Casimir Effect
·
· Score: 1
...I also know that last year they determined that a photon at rest DOES have mass,...
Nope. There's no such thing as a "photon at rest". A photon always travels at the speed of light.
However, you are correct that there is no such thing as an absolute vacuum. Since photons have mass (m=E/c^2), the only way to create an absolute vacuum is to take all particles and photons out, and that's not possible (microwave background radiation).
But! There is a quantum theory concept of zero-point energy. Like everything else in quantum physics, it's totally weird, and the Casimir effect is closely associated with it. There's more to it than your explanations, so maybe you should do a Google search on "zero-point energy".
So, I think it may be possible, and it isn't a perpetual motion machine in the traditional sense that all the energy is self contained. It a regular machine that taps into a sweet energy source of vacuum.
Yeah. That would violate the second law of thermodynamics, though (I think..). Maybe Congress can overturn the laws of physics...
No offense, your conclusions are (probably) right, but the way you arrive at them is flawed.
"No energy in, no energy out". This is fundamentally correct. However, it is not really possible to calculate how far a DeLorean could go on the energy in 12 car batteries, since there are too many unknowns, specifically the tire friction and the air resistance.
Furthermore, the weight of the car does not really matter. Yes, you need a certain amount of energy to accelerate the car, but in theory you gain this back when you let it coast to a stop.
First a few remarks about physics, though. A horsepower is a unit of power (indeed, ~ 735W), not of energy. A Watt is defined as 1 Joule per second. A Joule is defined as the amount of energy needed to exert a force of 1 Newton over 1 meter (darn metric system, where's the conversion constants?;-) Simple example: to lift a weight of 1 kilogram 1 meter up you would need an energy of about 10 Joules (or 9.8J, for the nitpickers). Power is an "intensity" unit. You would need 10 Watts of power to lift the weight in 1 second. Anyhow, horsepower doesn't have a lot to do with it. It's about the energy that you can store in 12 batteries.
Now, a regular battery holds about 50-60 Ah (Amps times hours) of charge. This simply means that the battery can deliver about 50A for an hour, or 5A for 10 hours, or 0.5A for 100 hours, etc. At least, theoretically, in reality these curves aren't perfectly linear, also due to the internal resistance of the battery, but the idea is pretty straightforward. So, assuming these are 12V batteries, their energy content is about 12V * 50A * 1 hour = 600W * 3600s = 2.16 MegaJoules. Multiply by 12 batteries and you get 25.92 MJ. Or, about 7.2 kiloWatthours (kWh) if that is more meaningful to you. How far can a DeLorean run on that? No idea. As I mentioned, it depends on the friction losses (also in the motor and transmission) and the air resistance (which is dependent on speed, especially at higher speeds).
We can try to express the energy in gallons of gasoline. Some googling reveals that 1 gallon of gas delivers around 132MJ. So, our 26MJ is rougly equivalent to 0.2 gallons of gas. Even assuming high efficiency and low friction, how far can you drive a DeLorean on that?
Do you not find it strange that a 2-hour DVD, with commentary, subtitles, and extra scenes, can be sold for less than $10, while few audio CDs are that low priced?
Consider this: on the one hand there is the cost of producing the product, but there's also the value of the product.
For me, the value of a CD is higher than that of a DVD, purely because I will (re)play a CD far more often than a DVD. Apart from the occasional classic movie, how often do you play a DVD more than once or twice? If I play an audio CD only once or twice, I obviously made a mistake when buying it. For some reason it takes a lot longer for music to get boring than a movie. Some of my CDs I have played hundreds of times.
Another factor is that you can play music in the background (i.e. while doing other things), whereas watching a movie demands almost 100% of your attention.
Anyhow, while I agree that CDs are overpriced, I think that an audio CD has more value than a DVD, if only for the sheer number of hours of usage.
Entirely correct. As a matter of fact, between the moment it enters the atmosphere and the moment of impact: 1 second if it enters at 90 degrees (angle), 1.4 seconds if it enters at 45 degrees, 2 seconds if it enters at 60 degrees, etc.
All this assuming a speed of about 50 km/s, and the thickness of the atmosphere being about 50 km. Rough assumptions, but the point should be clear.
Light pressure. Does not really have a lot to do with heating. The idea is that a light (colored) surface reflects more photons than a dark one, so there will be a difference in forces, ergo an alteration of trajectory. Sorta the same idea as light sails (but then a little different...).
Whether it would work, I don't know. All depends on mass, trajectory, and light pressure from the sun.
Assuming it's made of air and mylar, it would burst. There is about zero pressure in space. That's why astronauts have to have spacesuits, and those spacesuits are thick and expensive as h3ll. Knowing how relatively weak mylar is, the "air"bag would burst before entered space, due to the immense pressure difference.
Sorry, but that does not make sense. Yes, pressure in space is zero. So what? It's the pressure difference that matters. Some bicycle tires are inflated to 6 or 7 times atmospheric pressure. The difference between doing that on earth or in space is exactly 1 times normal atmospheric pressure.
Now, I don't exactly know how strong mylar is, but I'm sure they can make it thicker if it needs to be stronger.
"Immense pressure difference" does not make sense. It's not like you're dividing pressures, you're subtracting them (that's why they call it difference, I guess...)
I don't have one of these fast processors (yet), but I have been doing some AVI to MPEG2 encoding (home movies), and I can assure you that you can use every last bit of speed from the processor there. Currently using a 1.8 GHz P4, and boy, I sure could use some more horsepower...
Similarly, in the Netherlands the situation used to be the same: almost entirely government (taxpayer) funded, a few commercials every evening, in between programs. The Netherlands also has commercial TV stations now, most of the programming on them is complete and total garbage. The three public stations are the only ones worth watching in my humble opinion, and together they still attract 50% or so of the viewers.
Ah, but film also has its limitations. Resolving power (i.e. lines per mm) versus speed (i.e. ISO number, *not* frames per second) is a trade-off, as most everything in life. In simpler terms, faster film has more grain, thus less resolving power.
If I remember correctly, the 35mm film of choice for most professional photographers (Fuji Velvia, rated at ISO 50) has a resolving power of about 160 lines/mm, at a contrast ratio of 1000:1. A 35mm negative is 24x36mm, so that corresponds to 3840x5760 pixels, or 22.1 Mpixels (yes, you can't probably calculate it like that exactly, but it should be close enough). This is better than digital cameras can do, but digital cameras are getting close, and will probably reach this resolution in the near future. Also, note that I've assumed a perfect optical system (lenses).
Commenting on the 35mm print: I've done some experiments with 4x6 prints, and I came to the shocking conclusion that the resolution of these prints is somewhere between 200-300 dots/inch! Scanning at higher resolutions does not give better results! This is for 35mm negatives, medium or large format film will obviously give better results.
High-end photography is still done with film, that is true, but it won't be long until digital cameras will reach the same or better quality.
I for one don't plan on getting rid of my 35 mm SLR yet (I also have a digital point-and-shoot camera), but times are achanging quickly...
...especially if the advantages can't be reduced to a simple dollars-and-cents figure?
This hits the nail on the head. I make software for a living, and I can't imagine how I ever did my work without the Internet. E-mail, Web access, it all saves me quite a bit of time, and therefore the company money, but I would have a hard time trying to quantify these savings in dollars and cents.
I don't think IT departments will die. Virus checking, bug fixes, etc., it'll all still be necessary. People are getting more and more dependent on IT technology (wireless e-mail, web access). There is no way we are going to go back to snail mail and typewriters.
Now, delaying buying the latest and greatest hardware, and the latest and greatest version of MS Office, that I can see happening...
It is because the people that are interviewing you believe that the foreigners who get the job are so much better than you that they are worth the expense of hiring a H1B visa holder (it can be an expensive process).
"Expensive" all depends on how much money you have. The filing fees and legal fees can be thousands of dollars, but that should not be a big obstacle for a company. It's typically far less than a month's salary for the worker. I think it's more the fact that the whole process is a pain in the neck, it's not just the money.
By the way: $1000 filing fee, a $1000 premium processing fee, $130 administrative fee, all this money pays for jobs at the INS. What if you get laid off at the INS because the H1B program is canceled?
And then there's the legal fees to keep immigration lawyers employed...
Slashdot Mirror
In school copying was "bad", in software engineering we call it "reuse", and it's a Good Thing...
It should have been a +5 Funny, right? At least I hope so...I thought he was joking, but I'm not so sure any more. The fact that he gets a +5 Insightful is scary. You crackhead moderators are also joking by modding it as Insightful, right? I'm used to idiotic posts (that's what the mod system is for), but if the moderators are just as crazy, the system breaks down.
I guess I did not make myself clear, judging by the number of posters trying to educate me on the relationship between energy, power, and time :-)
Yes, given a certain amount of energy, a pulsed laser is far more effective than a continuous one.
An energy of 1 Joule in a nanosecond gives you a GigaWatt laser. The same energy in a millisecond only gives you a kiloWatt laser.
However, note that the article mentions that the power of the laser is 100 kW. It does not mention a fixed amount of energy.
Let me put it another way. Suppose we have two different lasers. Laser A has a power of 100kW, and delivers a 1 millisecond pulse, every second. Laser B also has 100kW of power, but delivers 1000 pulses of 1 millisecond, every second (so it's effectively a continuous laser). Which one is more effective? Laser A delivers 100J of energy every second. Laser B delivers 100,000J every second. (If you are going to argue now that laser A is a 100W laser, then I'm afraid I have confused you...).
Again, the fact that they need to dissipate 900kW, and use the fuel as a heat sink, leads me to believe that this is a (nearly) continuous laser. If it were using, say, a 1 millisecond pulse, they would need to dissipate 900J per pulse, which is not all that impressive.
Vent the steam. The F-35 is suppose to be stealthy. Leaving a con trail of vented steam does not help the stealth characteristics.
Furthermore, as an AC pointed out, these aerospace guys and completely and utterly paranoid about weight. I have worked on an aerospace program where a dual processor system was considered for the on-board computer. One of the arguments against the second processor was its weight (and the extra weigth to the power supply and heat sinks)! I don't blame you if you don't believe me, I could hardly believe it myself...
This is for a continuous wave laser (one that doesn't pulse). Now you can imagine what 100,000 watts will do:). The question is, seeing as how this must be firing in pulses, what is the pulse length? Minutes? Seconds? Milliseconds?
If the thing pulses, it only makes it less effective. Remember, it's 100,000 Watts, or 100,000 Joules per second. The longer the pulse (or continuous), the more energy it delivers. If it were to pulse for a microsecond, it would deliver 100 mJ per pulse, and that's not all that impressive.
The fact that the dissipation of 900 kW poses some challenges leads me to believe that this thing is operating in (nearly) continuous mode. However, at the end of the day, the energy will have to come from the fuel, so there's a limitation there.
Far more significant is the diameter of the beam. This determines the amount of Watts per square meter. Lasers tend to have fairly narrow beams at the source, however, they also diverge a bit. At a distance of several kilometers this might be significant. Also, atmospheric diffraction could be a problem (possibly solved by the adaptive optics mentioned in the article).
But, given all this, I'm still puzzled. Say you could focus these 100kW in a narrow beam of for example 1 millimeter. This could probably burn a hole through a tank or an airplane. But what's the point of burning a 1 mm hole in a tank or plane? How much damage does that do?
Alternatively, say the beam has a diameter of 1 meter. A one meter hole would probably do significant damage, especially to an airplane. However, that would amount to ~130kW per square meter, which is around 1000 times the intensity of the sun. That's about the same as using a (big) magnifying glass in sunny weather. How long would it take to burn a hole through anything? Especially tanks with their several feet of steel armor would survive this for quite some time, I would think.
Of course, it could be an anti-personnel weapon, but I have doubts on how effective this would be. What's the point of using an F-35 to pick off infantry troups one by one?
I guess I must be missing something here.
Numbskull moderator. Please mod parent up, it is not flamebait. The word "Nonsense" is actually from the SciAm article, it wasn't made up by the poster.
From the article:
Natural selection picked out the chemical basis of genetic information transfer probably because it was the best of the available options for ensuring fidelity in reading and copying information.
Assuming that they mean "selection" as in an evolutionary sense, I fail to see how this can be true. Isn't the whole genetic chemistry (ATCG, DNA, etc.) necessary before any selection can take place at all? In other words, isn't this a chicken-and-egg problem? You need a self-replicating structure before you can have reproduction, which is necessary for selection (right?). Or are we to believe that there was once a whole slew of competing chemicals, and our good friends A,T, C, and G won the grand prize because they had a 'parity check'? But even if you buy into that, where did the repairing enzymes come from? Aren't enzymes encoded by... (drumroll...) DNA? I'm a bit out of my area of expertise here (I ain't no biochemist), but it does seem a bit strange to me...
Darn! At first I thought this had to be wrong, since Sunday is the day of rest, so that had to be the seventh day, not the first. Then I realized that the Sabbath is the seventh day, so this date must be right.
I'll try to explain.
If the Universe is an ever expanding "sphere", then what is making it infinite?
Nothing. It's not infinite, it's finite.
You are correct that the universe has an outer sphere, however, this is not a physical boundary, it's determined by the speed of light and the age of the universe. According to Einstein nothing can travel faster than the speed of light. So, if the universe is 16 billion years old, then the universe has a radius of 16 billion light years. So, nothing can pass through the border, since the border is defined by the fastest traveling thing (i.e. light).
IIRC there are observations or theories that the universe is slowing it's expansion due to the fact that matter attracts matter.
Actually, the lastest observations indicate that the expansion is speeding up rather than slowing down.
Besides that, it is clear that the matter in the universe is not expanding at the speed of light (gravity slows it down, and matter can't travel at light speed in the first place), so photons have overtaken the farthest matter already anyway.
Again, the border of the universe is not determined by matter, but by photons.
Hope that didn't confuse matters too much...
In other news: not only did God decide to play a practical joke by burying fossils, He decided to bury them in order of complexity, i.e., the simpler the fossil, the deeper He buried it. A grinning God was quoted as saying: "If this doesn't make them believe in something silly like evolution, nothing will!".
Hmmm. According to The Nitpicker's Guide for Next Generation Trekkers by Phil Farrand (ISBN 1-85286-513-X, First Edition, 1993), Data still uses a contraction in Datalore: 'One of Data's last lines in this show is "I'm fine"...'. (page 36).
Since I don't have a tape of every episode in a magnetically shielded vault, I can't verify this. Guess it's too much to hope that you could remember it...
...but with DVDs, you get a lot more for your money...
I disagree. Yes, you get a lot more additional material, that's all true, but how often do you play a particular DVD? Two, three times? And how often do you play a particular CD? 10, 20, 100 times? There's more hours of entertainment in a CD, in my opinion. Music can be played over and over again, at least more often than a movie. Also, CDs can be played while you're doing something else, this is a lot harder with a DVD.
To further my point, I've purchased far more DVDs than CDs in the last year, and it's not because I watch more movies than I listen to music...
Maybe it is because the 'replayability' of CDs is much better? See my previous argument.
...I also know that last year they determined that a photon at rest DOES have mass,...
Nope. There's no such thing as a "photon at rest". A photon always travels at the speed of light.
However, you are correct that there is no such thing as an absolute vacuum. Since photons have mass (m=E/c^2), the only way to create an absolute vacuum is to take all particles and photons out, and that's not possible (microwave background radiation).
But! There is a quantum theory concept of zero-point energy. Like everything else in quantum physics, it's totally weird, and the Casimir effect is closely associated with it. There's more to it than your explanations, so maybe you should do a Google search on "zero-point energy".
So, I think it may be possible, and it isn't a perpetual motion machine in the traditional sense that all the energy is self contained. It a regular machine that taps into a sweet energy source of vacuum.
Yeah. That would violate the second law of thermodynamics, though (I think..). Maybe Congress can overturn the laws of physics...
No offense, your conclusions are (probably) right, but the way you arrive at them is flawed.
;-) Simple example: to lift a weight of 1 kilogram 1 meter up you would need an energy of about 10 Joules (or 9.8J, for the nitpickers).
"No energy in, no energy out". This is fundamentally correct. However, it is not really possible to calculate how far a DeLorean could go on the energy in 12 car batteries, since there are too many unknowns, specifically the tire friction and the air resistance.
Furthermore, the weight of the car does not really matter. Yes, you need a certain amount of energy to accelerate the car, but in theory you gain this back when you let it coast to a stop.
First a few remarks about physics, though.
A horsepower is a unit of power (indeed, ~ 735W), not of energy. A Watt is defined as 1 Joule per second. A Joule is defined as the amount of energy needed to exert a force of 1 Newton over 1 meter (darn metric system, where's the conversion constants?
Power is an "intensity" unit. You would need 10 Watts of power to lift the weight in 1 second.
Anyhow, horsepower doesn't have a lot to do with it. It's about the energy that you can store in 12 batteries.
Now, a regular battery holds about 50-60 Ah (Amps times hours) of charge. This simply means that the battery can deliver about 50A for an hour, or 5A for 10 hours, or 0.5A for 100 hours, etc. At least, theoretically, in reality these curves aren't perfectly linear, also due to the internal resistance of the battery, but the idea is pretty straightforward. So, assuming these are 12V batteries, their energy content is about 12V * 50A * 1 hour = 600W * 3600s = 2.16 MegaJoules. Multiply by 12 batteries and you get 25.92 MJ. Or, about 7.2 kiloWatthours (kWh) if that is more meaningful to you. How far can a DeLorean run on that? No idea. As I mentioned, it depends on the friction losses (also in the motor and transmission) and the air resistance (which is dependent on speed, especially at higher speeds).
We can try to express the energy in gallons of gasoline. Some googling reveals that 1 gallon of gas delivers around 132MJ. So, our 26MJ is rougly equivalent to 0.2 gallons of gas. Even assuming high efficiency and low friction, how far can you drive a DeLorean on that?
Do you not find it strange that a 2-hour DVD, with commentary, subtitles, and extra scenes, can be sold for less than $10, while few audio CDs
are that low priced?
Consider this: on the one hand there is the cost of producing the product, but there's also the value of the product.
For me, the value of a CD is higher than that of a DVD, purely because I will (re)play a CD far more often than a DVD. Apart from the occasional classic movie, how often do you play a DVD more than once or twice? If I play an audio CD only once or twice, I obviously made a mistake when buying it. For some reason it takes a lot longer for music to get boring than a movie. Some of my CDs I have played hundreds of times.
Another factor is that you can play music in the background (i.e. while doing other things), whereas watching a movie demands almost 100% of your attention.
Anyhow, while I agree that CDs are overpriced, I think that an audio CD has more value than a DVD, if only for the sheer number of hours of usage.
Entirely correct. As a matter of fact, between the moment it enters the atmosphere and the moment of impact: 1 second if it enters at 90 degrees (angle), 1.4 seconds if it enters at 45 degrees, 2 seconds if it enters at 60 degrees, etc.
All this assuming a speed of about 50 km/s, and the thickness of the atmosphere being about 50 km. Rough assumptions, but the point should be clear.
Light pressure. Does not really have a lot to do with heating. The idea is that a light (colored) surface reflects more photons than a dark one, so there will be a difference in forces, ergo an alteration of trajectory. Sorta the same idea as light sails (but then a little different...).
Whether it would work, I don't know. All depends on mass, trajectory, and light pressure from the sun.
Assuming it's made of air and mylar, it would burst. There is about zero pressure in space. That's why astronauts have to have spacesuits, and those spacesuits are thick and expensive as h3ll. Knowing how relatively weak mylar is, the "air"bag would burst before entered space, due to the immense pressure difference.
Sorry, but that does not make sense. Yes, pressure in space is zero. So what? It's the pressure difference that matters. Some bicycle tires are inflated to 6 or 7 times atmospheric pressure. The difference between doing that on earth or in space is exactly 1 times normal atmospheric pressure.
Now, I don't exactly know how strong mylar is, but I'm sure they can make it thicker if it needs to be stronger.
"Immense pressure difference" does not make sense. It's not like you're dividing pressures, you're subtracting them (that's why they call it difference, I guess...)
11 g is a heavy load, yes, for humans. There's nobody on board this thing. The avionics can easily withstand 11 g (and a lot more for that matter).
I don't have one of these fast processors (yet), but I have been doing some AVI to MPEG2 encoding (home movies), and I can assure you that you can use every last bit of speed from the processor there. Currently using a 1.8 GHz P4, and boy, I sure could use some more horsepower...
Similarly, in the Netherlands the situation used to be the same: almost entirely government (taxpayer) funded, a few commercials every evening, in between programs.
The Netherlands also has commercial TV stations now, most of the programming on them is complete and total garbage. The three public stations are the only ones worth watching in my humble opinion, and together they still attract 50% or so of the viewers.
Ah, but film also has its limitations. Resolving power (i.e. lines per mm) versus speed (i.e. ISO number, *not* frames per second) is a trade-off, as most everything in life. In simpler terms, faster film has more grain, thus less resolving power.
If I remember correctly, the 35mm film of choice for most professional photographers (Fuji Velvia, rated at ISO 50) has a resolving power of about 160 lines/mm, at a contrast ratio of 1000:1. A 35mm negative is 24x36mm, so that corresponds to 3840x5760 pixels, or 22.1 Mpixels (yes, you can't probably calculate it like that exactly, but it should be close enough). This is better than digital cameras can do, but digital cameras are getting close, and will probably reach this resolution in the near future. Also, note that I've assumed a perfect optical system (lenses).
Commenting on the 35mm print: I've done some experiments with 4x6 prints, and I came to the shocking conclusion that the resolution of these prints is somewhere between 200-300 dots/inch! Scanning at higher resolutions does not give better results! This is for 35mm negatives, medium or large format film will obviously give better results.
High-end photography is still done with film, that is true, but it won't be long until digital cameras will reach the same or better quality.
I for one don't plan on getting rid of my 35 mm SLR yet (I also have a digital point-and-shoot camera), but times are achanging quickly...
...especially if the advantages can't be reduced to a simple dollars-and-cents figure?
This hits the nail on the head. I make software for a living, and I can't imagine how I ever did my work without the Internet. E-mail, Web access, it all saves me quite a bit of time, and therefore the company money, but I would have a hard time trying to quantify these savings in dollars and cents.
I don't think IT departments will die. Virus checking, bug fixes, etc., it'll all still be necessary. People are getting more and more dependent on IT technology (wireless e-mail, web access). There is no way we are going to go back to snail mail and typewriters.
Now, delaying buying the latest and greatest hardware, and the latest and greatest version of MS Office, that I can see happening...
It is because the people that are interviewing you believe that the foreigners who get the job are so much better than you that they are worth the expense of hiring a H1B visa holder (it can be an expensive process).
"Expensive" all depends on how much money you have. The filing fees and legal fees can be thousands of dollars, but that should not be a big obstacle for a company. It's typically far less than a month's salary for the worker. I think it's more the fact that the whole process is a pain in the neck, it's not just the money.
By the way: $1000 filing fee, a $1000 premium processing fee, $130 administrative fee, all this money pays for jobs at the INS. What if you get laid off at the INS because the H1B program is canceled?
And then there's the legal fees to keep immigration lawyers employed...