The sun takes up.5 degrees in the sky. The light hitting the mirror from the "top" of the sun is not coming in parallel to the light from the "bottom" of the sun. There is an angle of.5 degrees. If the mirror were a point then at 100 feet the dispersion (in feet) would be approx. d= 100 * tan (.5) which is.87 feet. Now move to a 1 sq ft mirror. The top of this mirror is going to reflect light from the top of the sun down by.25 degress and light from the bottom of the sun up.25 degrees. Similar logic applies to the bottom of the mirror. So the light from the top at 100 feet is off of parallel by 100*tan(.25) or.436 feet and same for the bottom. This gives a height of 1.87 feet. Now do the same for the sides of the mirror and you get 1.87 for the sides so square it to get 3.49 square feet. Now the light in the central square foot is going to be more intense, but you are getting dispersion at 100 feet due to the angle of the sky that the sun occupies. BTW, the MIT site agrees with my math if you care to look it up.
Yes it does matter. This is why at 100 ft the reflected light from a 1 square foot mirror occupies 3 square feet. If your target is 100 feet away you need three times the number of mirrors that you think you would need. Go do the math. The sun takes up about a half a degree in the sky.
If you continue to insist that you are right, what distance would the ships have to be at for it to matter and why?
I'll admit that I don't have the physics degree you have. Just a lowly CS degree from Stanford, so I could be wrong.
The dinky town I mentioned is in souwthwestern Wyoming... I guess you might have a hard time finding anything in say, Randolph or Woodruff, but you really have to be trying to avoid towns with truck stops.
I am also from the "American West" as you call it. I have driven to many out of the way places and find it hard to imagine that you couldn't easily find headphones. I do believe that you could find many stores that don't carry them.
the only stores for thousands of miles in any direction sold only alcohol, Mormon cookbooks, and knives.
Now that is an odd combination. Where on earth were you driving? It is pretty hard to go for eight hours (even out west) and not find a place that will sell headphones. Even places as obscure as Cokeville, WY have them at truckstops.
Longest drive we've taken with the kids is 6 hours. While there were obvious preferences they didn't latch onto one particular thing and demand it over and over. In any case, you have proved my point, which is that you should bring everything with you all the time, and isn't an iPod a better way to do that than a pack of DVDs?
Honestly, the new iPod seems like a proof of concept more than the destination. It is going to have to support HD, or at least HD output in the near future to be relevant. The two situations are not perfect parallels. There are several other differences, including the ability to rip CDs vs DCMA protected DVDs and the presence of the iTunes store (there at launch for video, not there for iPod).
Some consumers really care about HD. Many don't right now. This will be more of an issue in two years, by which time there will be a product to accomodate HD. I wouldn't be surprised if the next rev (in a year?) has a widescreen and HD support.
Fine, put is on a 56 inch HD plasma TV and hook up an iPod dock to it. Then control the iPod with that clever little remote. The difference between TVs and monitors is going away anyhow in some ways.
I think everybody should go watch the Oct 12 video on the Apple website. For one thing, it has the Eminem add that was pulled. But more importantly everyone should sit down and pay close attention to what the iMac does now and how Steve compared the remote that comes with it to the MS Media Center remotes. Now is anybody really going to use a 17 inch iMac as a TV replacement? Probably not. Maybe in the kitchen, but I doubt it.
So is Steve just smoking crack here? Of course not. Now consider the Apple 30" cinema display hooked up to that remote. Things become a bit more compelling, don't they? Am I saying that Apple is going to make a Tivo? They might, but I'm guessing they won't. Here's why. The broadcasters hate Tivo. To them, Tivo means they just gave away the show AND the viewer skipped the ads. Same goes for BitTorrent, which has content producers frightened even more. Apple is offering them an alternative. Try to capture some of the Tivo/BT market by selling the show a day later with no ads. That way the broadcaster gets paid, and paid fast. The home viewer can watch the show on their Apple set top box or on the iPod. My guess is that the iTunes video store will start to grow to include older shows and eventually movies.
One thing nobody has mentioned is HD. Obviously the current iPods can't do it, but it won't be long. Apple is playing this smart, leveraging the popularity of the iPod and iTunes to establish the relationships with content producers that will get them on board.
Finally, another thing that nobody has mentioned is video in the car. If you have kids you know that a DVD player is not the best solution in the world. Not only do you have to mess with disks, but many children's disks are only about 20 minutes long and looping that over and over again on a long drive will make you want to murder Thomas, Percy, Gordan, and even Edward. What if instead you could put all your kids' shows on an iPod and hook that up to the screen in the car instead? Parents across the nation will go nuts for this and will download content just to keep themselves sane by avoiding repetition. I know that if I get one of these I'm going to rip all the Sesame Street and Thomas DVDs we have to it immediately and then park the thing in the car. And yes you can do it, just not with Apple software, for now at least.
It should also be mentioned that at least the Stanford team and the CMU team claim to have completed the old course while preparing for this year's event. So even if this year's course is easier, there are some teams that completed the old course anyhow. Obviously this wasn't under race conditions (the most important condition being that you don't know the course until just before the race) but it is still relevant.
forget the DVD+-R tech. Buy a USB attached hard disk and put EVERYTHING on it. Buy two and send on across the country. DVD media means you have to re-burn every few years or lie awake at night wondering if your data is corrupted.
I agree. Every phone company I've ever had has made at least one mistake that ended up with me being billed over $500. I always resolve it eventually, but sometimes it takes months. Verizon was able to resolve it in two days, which is some sort of record.
Even if Qwest doesn't sell lists, telemarketers can still get your number.
How? I use a cell phone for almost all personal calls. I have the landline for long conf calls on 800 numbers. So Qwest is the only organization that has my number associated with my name.
Perhaps you can tell me this since Qwest won't. I just moved and got a new land line from Qwest. Mostly to get cheaper DSL than I would without a land line. In any case I got an unlisted number that I haven't given out. Since then I get several calls a day from telemarketers who already know my name. I politely ask them were they got my number and every one of them has said that they bought the list from Qwest. Qwest of course denies this. Does Qwest sell lists?
In any case I am rather upset that I have a brand new number that is already polluted.
No offense taken. Your solution works for you and provides a level of security and that is great. For a large organization though buying a password management system can make a lot of sense and it can enable things you might not have thought of. For instanct, you can have password randomization such that users don't (and can't) even know their own passwords. You can generate cryptographic keys on the card for signing and have keys for encryption and authentication. So the solutions I mention can do things that the PDA can't.
There are products out there from companies such as ActivCard and Protocomm that will securely store your passwords and also enter them via a script. Generally the use has to remember one password (called a PIN) to open up their smart card and then they don't need to remember anything else. Having a token and a single comples password (and/or a biometric) is generally more secure than trying to juggle dozens of individual passwords.
Disclaimer: I install such systems for a living, so I might be a bit biased.
Slashdot Mirror
The sun takes up .5 degrees in the sky. The light hitting the mirror from the "top" of the sun is not coming in parallel to the light from the "bottom" of the sun. There is an angle of .5 degrees. If the mirror were a point then at 100 feet the dispersion (in feet) would be approx. d= 100 * tan (.5) which is .87 feet. Now move to a 1 sq ft mirror. The top of this mirror is going to reflect light from the top of the sun down by .25 degress and light from the bottom of the sun up .25 degrees. Similar logic applies to the bottom of the mirror. So the light from the top at 100 feet is off of parallel by 100*tan(.25) or .436 feet and same for the bottom. This gives a height of 1.87 feet. Now do the same for the sides of the mirror and you get 1.87 for the sides so square it to get 3.49 square feet. Now the light in the central square foot is going to be more intense, but you are getting dispersion at 100 feet due to the angle of the sky that the sun occupies. BTW, the MIT site agrees with my math if you care to look it up.
Yes it does matter. This is why at 100 ft the reflected light from a 1 square foot mirror occupies 3 square feet. If your target is 100 feet away you need three times the number of mirrors that you think you would need. Go do the math. The sun takes up about a half a degree in the sky.
If you continue to insist that you are right, what distance would the ships have to be at for it to matter and why?
I'll admit that I don't have the physics degree you have. Just a lowly CS degree from Stanford, so I could be wrong.
The sun is not a point source. Even with a flat mirror there will be some dispersion due to the diameter of the sun.
What does that have to do with lightbulbs? Your statement deals with heating in general.
I got mine for $396 delivered. It showed up today and is hooked up to my Mac mini. It is a beautiful display. I'm happy with it so far.
The dinky town I mentioned is in souwthwestern Wyoming... I guess you might have a hard time finding anything in say, Randolph or Woodruff, but you really have to be trying to avoid towns with truck stops.
I am also from the "American West" as you call it. I have driven to many out of the way places and find it hard to imagine that you couldn't easily find headphones. I do believe that you could find many stores that don't carry them.
Now that is an odd combination. Where on earth were you driving? It is pretty hard to go for eight hours (even out west) and not find a place that will sell headphones. Even places as obscure as Cokeville, WY have them at truckstops.
Longest drive we've taken with the kids is 6 hours. While there were obvious preferences they didn't latch onto one particular thing and demand it over and over. In any case, you have proved my point, which is that you should bring everything with you all the time, and isn't an iPod a better way to do that than a pack of DVDs?
Why didn't you tell me this sooner? I could have saved a ton on the car we just bought...
I am guessing that "sour grass" is actually the name of one of the scientists involved translated incorrectly.
In case you're interested, and you seem to be, my children watch TV exclusively in the car. They're not TV addicted, I'm just a happier driver.
Honestly, the new iPod seems like a proof of concept more than the destination. It is going to have to support HD, or at least HD output in the near future to be relevant. The two situations are not perfect parallels. There are several other differences, including the ability to rip CDs vs DCMA protected DVDs and the presence of the iTunes store (there at launch for video, not there for iPod). Some consumers really care about HD. Many don't right now. This will be more of an issue in two years, by which time there will be a product to accomodate HD. I wouldn't be surprised if the next rev (in a year?) has a widescreen and HD support.
Fine, put is on a 56 inch HD plasma TV and hook up an iPod dock to it. Then control the iPod with that clever little remote. The difference between TVs and monitors is going away anyhow in some ways.
You just add sour grass to the existing fuel mix, right?
I think everybody should go watch the Oct 12 video on the Apple website. For one thing, it has the Eminem add that was pulled. But more importantly everyone should sit down and pay close attention to what the iMac does now and how Steve compared the remote that comes with it to the MS Media Center remotes. Now is anybody really going to use a 17 inch iMac as a TV replacement? Probably not. Maybe in the kitchen, but I doubt it.
So is Steve just smoking crack here? Of course not. Now consider the Apple 30" cinema display hooked up to that remote. Things become a bit more compelling, don't they? Am I saying that Apple is going to make a Tivo? They might, but I'm guessing they won't. Here's why. The broadcasters hate Tivo. To them, Tivo means they just gave away the show AND the viewer skipped the ads. Same goes for BitTorrent, which has content producers frightened even more. Apple is offering them an alternative. Try to capture some of the Tivo/BT market by selling the show a day later with no ads. That way the broadcaster gets paid, and paid fast. The home viewer can watch the show on their Apple set top box or on the iPod. My guess is that the iTunes video store will start to grow to include older shows and eventually movies.
One thing nobody has mentioned is HD. Obviously the current iPods can't do it, but it won't be long. Apple is playing this smart, leveraging the popularity of the iPod and iTunes to establish the relationships with content producers that will get them on board.
Finally, another thing that nobody has mentioned is video in the car. If you have kids you know that a DVD player is not the best solution in the world. Not only do you have to mess with disks, but many children's disks are only about 20 minutes long and looping that over and over again on a long drive will make you want to murder Thomas, Percy, Gordan, and even Edward. What if instead you could put all your kids' shows on an iPod and hook that up to the screen in the car instead? Parents across the nation will go nuts for this and will download content just to keep themselves sane by avoiding repetition. I know that if I get one of these I'm going to rip all the Sesame Street and Thomas DVDs we have to it immediately and then park the thing in the car. And yes you can do it, just not with Apple software, for now at least.
It should also be mentioned that at least the Stanford team and the CMU team claim to have completed the old course while preparing for this year's event. So even if this year's course is easier, there are some teams that completed the old course anyhow. Obviously this wasn't under race conditions (the most important condition being that you don't know the course until just before the race) but it is still relevant.
forget the DVD+-R tech. Buy a USB attached hard disk and put EVERYTHING on it. Buy two and send on across the country. DVD media means you have to re-burn every few years or lie awake at night wondering if your data is corrupted.
I agree. Every phone company I've ever had has made at least one mistake that ended up with me being billed over $500. I always resolve it eventually, but sometimes it takes months. Verizon was able to resolve it in two days, which is some sort of record.
How? I use a cell phone for almost all personal calls. I have the landline for long conf calls on 800 numbers. So Qwest is the only organization that has my number associated with my name.
none of them have this number. At least I haven't given it to them. The phone company is the only entity that has my number.
In any case I am rather upset that I have a brand new number that is already polluted.
No offense taken. Your solution works for you and provides a level of security and that is great. For a large organization though buying a password management system can make a lot of sense and it can enable things you might not have thought of. For instanct, you can have password randomization such that users don't (and can't) even know their own passwords. You can generate cryptographic keys on the card for signing and have keys for encryption and authentication. So the solutions I mention can do things that the PDA can't.
You might have missed it, but IBM announced cancellable biometerics a few weeks ago. I'm sure that you could google it, I'm too lazy/busy.
Disclaimer: I install such systems for a living, so I might be a bit biased.