Actually, light from distant stars isn't disappated by anything that doesn't scatter it-- Dust, gases, etc...
Distant stars appear less bright because light intensity, like most phenomena, drops with the squre of the distance from its source. From a power perspective (and your eyes are power meters, for all intents and purposes), if a star has an output of a hundred trillion megawatts (kinda puny, isn't it-- 100e18 W) and that power is emmitted evenly in all directions, than the power at a receiver (your eye) is directly proportional to the ratio of receiver size to sphere-size, where sphere-size is the size of a sphere with radius equal to the distance between power source and receiver.
For a star four light-years away, r=9.467e15 meters. Your pupil has a surface area of approximately 1 square cm, or 314e-6 m. That means that your eye is capable of receiving only (280e-37)% of the power that the star produced. For our hundred-trillion-megawatt star, that's 28e-18 W, or -165.5 dBW. That's pretty dim.
For a sense of scale, if we are on the surface of that star, and it's radius is 1.3e6 km (1.3e9 m, which means that the power output of the star is only 4.7 Watts per square meter), our eyes can detect 14.8e-6 W, or -48 dBW. Obviously *much* brighter.
In any case, it's obvious that perceived brightness is more a function of distance than anything.
Certainly seems that way, although the article does say that game publishers have the option of using less restrictive licensing arrangements.
You know, if this had happened twenty years ago, the flourishing computer/technology industry we see today for home electronics would not be even a shadow of what it has become. I've never seen so many people (publishers of various sorts) so upset about so few people doing so little (casual copying).
I imagine that it's just a sign of the greatness of the world we live in: people have come to worry about the most minute things imaginable.
Actually, most of the bibles you see placed in hotels are put there by the Gideons. I have known a few people that were members of this organization.
Although they are evangelists they are not, "rolling in billions of dollars." They are people that work like everyone else. They don't ask for handouts, although they do accept them. I don't know any of them that own gold thrones with velvet seats.
As far as Bible publishing goes, it's the all-time best seller, bar none. It continues to generate top sales, almost seventeen hundred years after being canonized.
The Power Wheels vehicles I remember came along when I was about twice the age of the target, uh, drivers.
I remember three- and four-wheel ATV type things and a miniature four-wheel-drive-looking pickup. Used gel-cell batteries that were way expensive. I used to load them up for people when I worked at Wal-Mart.
Every atom has a certain frequent movement. Objects consisting of a large number of atoms stay in one place because the movement of all those atoms combined adds up to zero.
That's not right. Solid objects are held together not by luck, as you seem to be saying, but by electrostatic (chemical) bonds that are formed when atoms share electrons to form molecules. These molecules can become large and visible by themselves (crystals), or become intertwined and lock together (like plastics). These chemical bonds, while somewhat flexible, limit the range of motion of individual atoms. Atoms and molecules do vibrate, and it is this vibrations that we sense as temperature.
Now what you say is true of fluids, and ideal gases in particular. But not solids.
However, like you said, migration is an issue in certian situations. When atoms are not held in place by chemical bonds they can indeed float around. Gold from a plated PWB will leech into the lead of a solder joing, brittling it.
I'd be more concerned about ESD. With such a thin gate insulator, these FETs are going to be extremely ESD sensitive. They're going to suffer punch-through at very low static voltages, since the field strength in the region of the insulator is going to be astronomical due to the short insulator length [Field strength = (applied voltage)/(distance between charges)]
The American GPS system is used by both the military and civilians. Up until a few years ago, the civilian users only had access to signals degraded by "Selective Availability," and were only good to +/- 300 meters or so.
Of late, SA has been turned off, and now both civilian and military users have the high-accuracy signal. This was in part due to the FAA's efforts to "undo" SA though their WAAS, Wide Area Augmentation System. WAAS stations near major airports would provide additional resolution to SA-crippled GPS so that precision approaches based on GPS could be created. Currently GPS approaches are non-precision (lateral guidance only, no altitude guidance), and usually are overlays of existing VOR or NDB approaches.
Thanks. Now I have to clean my keybard aftr yur ZW gg made me spll m Cke ll vr t.
Re:Sad that Amercans are reduced to this ?
on
Solar Sails
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· Score: 1
Not to mention the fact that Lois Lane was played by Margo Kidder in the movies!
Re:This is part of our destiny.
on
Solar Sails
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· Score: 4
I read that link you posted, and I am unimpressed. All they did was prove that the phase velocity of a propagating EM field can indeed go faster than c. The article even mentions the sweeping beam of a lighthouse. If we assume that the beam is rotating with an angular velocity P, then at some point away from the lighthouse r, the linear velocity of the beam v will be equal to c: v = Pr. That's easily determined: r = c/P. Beyond this radius the linear velocity of the beam will be greater than c even though the beam propigation in the r direction will be only equal to c.
Of course, if you wanted to send a signal faster than c, the group velocity of that EM field would have to exceed c, which it doesn't.
Since the speed of light, c, is determined by whatever the substance is that the EM field is propagating through by the equation
c = 1/sqrt(u*e)
Where u is the permeability of the substance and e is the permittivity. Each of these values is made up of two parts, the intrinsic value and the relative value. The intrinsic permeability of free space (u0) is 1.257e-6 H/m. The intrinsic permittivity of free space (e0) is 8.854e-12 F/m. In a vacuum the relative permeability and the relative permittivity are both 1. This gives a free-space value for c of 2.998e8 meters/sec.
In a non-vacuuum, either or both of the relative terms will be greater than 1, and the value of c in those mediums will be less than the free-space value.
The key to propagating signals faster than 3e8 m/sec is to find a material with a dielectric constant (relative permittivity) between zero and 1. These materials don't exist, however.
I'm not sure I'd call Central America a contenent by itself. Isn't it actually part of North America, and properly an isthmus between N. America and S. America?
Actually, "America" is not a continent. There's two-- North America and South America, and taken together they're the "Americas." "America" is used, however, as an abbreviated name for The United States of America, even though we all admit numerous other soveriegn countries on the Americas.
There's still no "USia," however. If you had said "USoA," fine-- United States of America. There is no place called "USia," however.
And no, you didn't say "boxen." I was just getting all the ire out a once. I'm glad that you agree that "boxen" looks uneducated. I made the (wrong) generalization that (one that would say "USia")==(one that would say "boxen") since both sound uneducated.
I'm so sick of this 31337 writing style, it just grates on my nerves...
sharkticon wrote:
USia
Where's this USia? The proper name of the country I think you're referring to is "The United States of America," and is sometimes referred to as the "USA" or "America." I also happen to like "The United States," although that might be ambiguous.
Also, "USA" is not pronounced as a word, it's/YOO-ESS-AY/.
Furthermore, if you intended to use "USia" as you would use "Asia," remember that there are several other countries in North America. Canada and Mexico, for instance. As far as I know, they're still independent, soveriegn nations
Furthermore, in case in the future you want to write a plural for the word "box," let me remind you that it's "boxes" and not "boxen." Just because there's an animal with a name that rhymes and has a wierd plural form doesn't mean that all words that end in X have plurals formed that way. Saying "boxen" just makes you look uneducated.
I admit that sometimes I say "England" when I mean "United Kingdom," but the part of the UK that I'm talking about when I say that is England. I just forget that I might be talking about Scotland, Ireland, the Falkland Islands and other places as well.
What time signature is it in? If it's 4/4 time, that music is only 3.6 notes per second (assuming all quarter notes). A quarter note is held for one beat; it'd have to be all sixteenth notes to be as fast as you say.
Several weeks ago I posted a bug report to CodeWeaver's BugZilla site. I see that it's been assigned to somebody, at least. Wine is very close to being useful without actually making it. I just wish I could get disk accesses to work!
In the almost two years we've had DirecTV, the bills have gone up almost ten dollars. I do admit that five of those dollars go to get the local (Orlando) channels.
My wife and I are pretty happy with the service (other than rain fade margins-- they don't exist!) and think that we made the right choice over going with TWC. One of her teacher colleagues has TWC digital cable, and the picture is awful compared to DirecTV. (Except in those summer monsoons when DirecTV doesn't work at all!)
I have never been comfortable with people getting these kinds of services without paying for them. That monthly bill not only pays for the programming, but also on infrastructure and maintenance. Hughes played a HUGE gamble by launching its DirecTV bird. Unlike cable, satellite systems must have their entire infrastructure in place before they can sign their first subscriber. Cable systems can roll out a piece at a time, and early adoptors help pay to expand into new areas.
The only thing I'd like Hughes to add is a non-Windows bidirectional link for DirecPC and a dual-subscriber discount like TWC has with RoadRunner.
Many receivers are not passive, but include in themselves local oscillators that operate very near the band of reception. These LOs are used to mix the RF signal down to an intermediate frequency for processing, and some radios use multiple LOs to provide better signal selectivity.
The FCC considers these kinds of receivers to be "unintentional radiators," and they CAN cause interference.
That's the whole point. It's funny because everyone around the table knows it's impossible. We'd all like to have the stuff, but it's Unobtainium.
Also, thanks for the defense, but I don't think that people posting as AC pose much of a threat; their insults don't mean much if they are not upset enough to log in.
Seriously, the dielectric constant of current PC board materials has become a bit of a hinderance. Standard board etching shops have minimum features sizes of five-mil (1/1000 inch == 1 mil) lines and spaces. The cheapy places want even LARGER minimum features.
One can cheat for a while and just use a thicker substrate, but that only works until the frequency of operation approaches that of the next higher-order mode. In stripline, there is a frequency for a given board thickness at which the energy "leaks" off the trace and disperses into the board as a parallel-plate waveguide mode. Stripline circuits must work well below that frequency to ensure effecient energy guidance. Lower dielectric constant materials would allow the use of thinner substrates for a given minimum feature size and extend the useful frequency range.
Of course, it's probably all moot anyway: as the frequency of operation increases, the conductor loss starts to dominate and pretty soon your super-high-frequency transmission line becomes a very fancy electric heater.:( Nothing is free.
That's a joke I always bring up with PC board material vendors. As we use higher and higher frequency bands (we're about to start a 40 GHz comm system), circuit elements get unmanufacturably small. I often ask the less cluefull salespeople if they could provide us with board materials with relative dielectric constants less than one (speed of light in material == c/sqrt(Er) ). I usually get a chuckle or two.
Slashdot Mirror
Some people have no sense of humor this early in the morning. Gotta be careful with those posts, donchaknow.
Distant stars appear less bright because light intensity, like most phenomena, drops with the squre of the distance from its source. From a power perspective (and your eyes are power meters, for all intents and purposes), if a star has an output of a hundred trillion megawatts (kinda puny, isn't it-- 100e18 W) and that power is emmitted evenly in all directions, than the power at a receiver (your eye) is directly proportional to the ratio of receiver size to sphere-size, where sphere-size is the size of a sphere with radius equal to the distance between power source and receiver.
For a star four light-years away, r=9.467e15 meters. Your pupil has a surface area of approximately 1 square cm, or 314e-6 m. That means that your eye is capable of receiving only (280e-37)% of the power that the star produced. For our hundred-trillion-megawatt star, that's 28e-18 W, or -165.5 dBW. That's pretty dim.
For a sense of scale, if we are on the surface of that star, and it's radius is 1.3e6 km (1.3e9 m, which means that the power output of the star is only 4.7 Watts per square meter), our eyes can detect 14.8e-6 W, or -48 dBW. Obviously *much* brighter.
In any case, it's obvious that perceived brightness is more a function of distance than anything.
You know, if this had happened twenty years ago, the flourishing computer/technology industry we see today for home electronics would not be even a shadow of what it has become. I've never seen so many people (publishers of various sorts) so upset about so few people doing so little (casual copying).
I imagine that it's just a sign of the greatness of the world we live in: people have come to worry about the most minute things imaginable.
Although they are evangelists they are not, "rolling in billions of dollars." They are people that work like everyone else. They don't ask for handouts, although they do accept them. I don't know any of them that own gold thrones with velvet seats.
As far as Bible publishing goes, it's the all-time best seller, bar none. It continues to generate top sales, almost seventeen hundred years after being canonized.
I remember three- and four-wheel ATV type things and a miniature four-wheel-drive-looking pickup. Used gel-cell batteries that were way expensive. I used to load them up for people when I worked at Wal-Mart.
Perhaps he meant that as flamebait.
Now what you say is true of fluids, and ideal gases in particular. But not solids.
However, like you said, migration is an issue in certian situations. When atoms are not held in place by chemical bonds they can indeed float around. Gold from a plated PWB will leech into the lead of a solder joing, brittling it.
I'd be more concerned about ESD. With such a thin gate insulator, these FETs are going to be extremely ESD sensitive. They're going to suffer punch-through at very low static voltages, since the field strength in the region of the insulator is going to be astronomical due to the short insulator length [Field strength = (applied voltage)/(distance between charges)]
The American GPS system is used by both the military and civilians. Up until a few years ago, the civilian users only had access to signals degraded by "Selective Availability," and were only good to +/- 300 meters or so.
Of late, SA has been turned off, and now both civilian and military users have the high-accuracy signal. This was in part due to the FAA's efforts to "undo" SA though their WAAS, Wide Area Augmentation System. WAAS stations near major airports would provide additional resolution to SA-crippled GPS so that precision approaches based on GPS could be created. Currently GPS approaches are non-precision (lateral guidance only, no altitude guidance), and usually are overlays of existing VOR or NDB approaches.
Thanks. Now I have to clean my keybard aftr yur ZW gg made me spll m Cke ll vr t.
Of course, if you wanted to send a signal faster than c, the group velocity of that EM field would have to exceed c, which it doesn't.
Since the speed of light, c, is determined by whatever the substance is that the EM field is propagating through by the equation
c = 1/sqrt(u*e)
Where u is the permeability of the substance and e is the permittivity. Each of these values is made up of two parts, the intrinsic value and the relative value. The intrinsic permeability of free space (u0) is 1.257e-6 H/m. The intrinsic permittivity of free space (e0) is 8.854e-12 F/m. In a vacuum the relative permeability and the relative permittivity are both 1. This gives a free-space value for c of 2.998e8 meters/sec.
In a non-vacuuum, either or both of the relative terms will be greater than 1, and the value of c in those mediums will be less than the free-space value.
The key to propagating signals faster than 3e8 m/sec is to find a material with a dielectric constant (relative permittivity) between zero and 1. These materials don't exist, however.
I thought lawyers got a % of the award, normally. I guess I'm in the wrong kind of work.
I was going to call it by it's buzzword-- "Design Re-Use"
There's still no "USia," however. If you had said "USoA," fine-- United States of America. There is no place called "USia," however.
And no, you didn't say "boxen." I was just getting all the ire out a once. I'm glad that you agree that "boxen" looks uneducated. I made the (wrong) generalization that (one that would say "USia")==(one that would say "boxen") since both sound uneducated.
sharkticon wrote:
Where's this USia? The proper name of the country I think you're referring to is "The United States of America," and is sometimes referred to as the "USA" or "America." I also happen to like "The United States," although that might be ambiguous.Also, "USA" is not pronounced as a word, it's /YOO-ESS-AY/.
Furthermore, if you intended to use "USia" as you would use "Asia," remember that there are several other countries in North America. Canada and Mexico, for instance. As far as I know, they're still independent, soveriegn nations
Furthermore, in case in the future you want to write a plural for the word "box," let me remind you that it's "boxes" and not "boxen." Just because there's an animal with a name that rhymes and has a wierd plural form doesn't mean that all words that end in X have plurals formed that way. Saying "boxen" just makes you look uneducated.
I admit that sometimes I say "England" when I mean "United Kingdom," but the part of the UK that I'm talking about when I say that is England. I just forget that I might be talking about Scotland, Ireland, the Falkland Islands and other places as well.
A whole note is four beats long in 4/4 time.
My wife and I are pretty happy with the service (other than rain fade margins-- they don't exist!) and think that we made the right choice over going with TWC. One of her teacher colleagues has TWC digital cable, and the picture is awful compared to DirecTV. (Except in those summer monsoons when DirecTV doesn't work at all!)
I have never been comfortable with people getting these kinds of services without paying for them. That monthly bill not only pays for the programming, but also on infrastructure and maintenance. Hughes played a HUGE gamble by launching its DirecTV bird. Unlike cable, satellite systems must have their entire infrastructure in place before they can sign their first subscriber. Cable systems can roll out a piece at a time, and early adoptors help pay to expand into new areas.
The only thing I'd like Hughes to add is a non-Windows bidirectional link for DirecPC and a dual-subscriber discount like TWC has with RoadRunner.
The FCC considers these kinds of receivers to be "unintentional radiators," and they CAN cause interference.
What happens when the wafers get all crinkeled up like my newspapers?
Also, thanks for the defense, but I don't think that people posting as AC pose much of a threat; their insults don't mean much if they are not upset enough to log in.
Seriously, the dielectric constant of current PC board materials has become a bit of a hinderance. Standard board etching shops have minimum features sizes of five-mil (1/1000 inch == 1 mil) lines and spaces. The cheapy places want even LARGER minimum features.
One can cheat for a while and just use a thicker substrate, but that only works until the frequency of operation approaches that of the next higher-order mode. In stripline, there is a frequency for a given board thickness at which the energy "leaks" off the trace and disperses into the board as a parallel-plate waveguide mode. Stripline circuits must work well below that frequency to ensure effecient energy guidance. Lower dielectric constant materials would allow the use of thinner substrates for a given minimum feature size and extend the useful frequency range.
Of course, it's probably all moot anyway: as the frequency of operation increases, the conductor loss starts to dominate and pretty soon your super-high-frequency transmission line becomes a very fancy electric heater. :( Nothing is free.
This should have been moderated funny, and not offtopic. If I had points I'd have undone this travesty.
When the mod points come my way, I think before using them. Perhaps that's the problem. People don't think enough around here.
After further consideration, that's too easy. Obvious even :)
As Homey the Clown would say, "I don't think so."