I guess I was wrong: Character_assasin is not reasonable after all.
But back to your point. Our Brazillian friend has been in the USA for 2+ years now, and hence is using the term "social networking" so he can get the point across to the english-speaking audience.
Guess you didn't realize he was writing in english in a vain attempt to communicate a message to you. In the future, I recommend a friendlier demeanor in slashdot discussions. Shouldn't be too hard for an aggressive "social networker" like yourself, right?
character_assassin, you seem like a reasonable guy. But do tell me, how many brazillians do you know?
Americans need the word "social networking" to describe the concept of.... being friendly? What's wrong with "hanging out", "socialize", "become friends"? You go "network" at a business conference, since "socialize" is a no-no during work hours, right? (No need to reply, purely rhetorical).
You know what? Brazillians don't make such distinction. Portuguese doesn't even have a word for our concept of "social networking", as far as I know. I think someone needs to go do some traveling...
And one last thing, are you telling me that at no point in your life were your friends actually strangers to you? If you're never nice to strangers, how the heck did you ever make friends in a new setting? (rhetorical)
irrelevant how many Brazilians I know.
character_assassin, you simply don't know what you're talking about because I highly doubt that you personally know any brazillians. I've lived in Brazil and in the US for over a decade (each), and yet, I'm not a native of either country. I can tell you objectively that, on average, there is a much higher probability of a random brazillian national being friendly to you off the streets of Sao Paulo (the "wall-street" financial center of Brazil), than of a random american being friendly to you in New York City.
For instance, a Kitty Genovese type of incident would be completely out of character for Sao Paulo . In NYC, such apathy is almost expected. So yes, brazillians ARE more gregarious than americans. More friendly not only towards each other, but also towards strangers.
Of course they can produce single photons. You must have missed that issue of Physical Review Letters (only the most pretigious journal of physics), here's a copy of the article:
The original poster's comment about the effect of gravity was... ahem, cryptic. I think this is what what he meant:
A rocket 50 meters tall will traverse a distance of 4.9 meters in 1 second, assuming it starts from rest and accelerates at 9.8 m/s^2 (we're assuming the rocket's upwards acceleration is just enough to match gravity). Thus, the distance covered is only about 10% of the total rocket length.
Imagine you're watching a movie. The natural inclination of the videographer is to make the rocket fit the frame height exactly. After 1 second, you see 10% of the rocket move off-screen (the camera is in fixed position).
If a mini rocket is only 5 meters tall, it traverse the same distance (4.9 meters) in the same time (1 second), given the same upwards acceleration of 9.8 m/s^2. Thus the distance traveled is total length of the rocket (5m).
If the videographer was filming this, he'd still zoom in so the 5 meter rocket would fit the vertical frame size exactly. But now, from your point of view, the movie-viewer, after 1 second the whole rocket is off-screen!
In essence, the physics are similar, but the intended effect is not. One can't just scale down everything by a factor of x, since the equations are non-linear. We can fix our mini-rocket by making it accelerate slower, but that'd change the thrust equations since gravity is still 9.8 m/s^2 at this scale!
So yes, gravity 'effect' will be different, but yes, the physics are still the same!
Dalton (a chemist) proposed this atomic theory in 1803. 'Chemists' of the time were convinced, but the real scientists, physicists, weren't.
In 1906 Boltzmann (a physicist) committed suicide because his theories, based on the atomic postulate, were not well-received. During a physics conference at the turn of the century, he was the only one to defend the atomic model. Other physicists of the time simply didn't buy it.
in 1914 Rutheford (a physicist) finally verified experimentally the structure of the atom in a series of scattering experiments. One can't argue with experimental data. Physicists were finally convinced. (The folly of chemists can be demonstrated even today: ask them about their beloved Convervation of Mass 'law').
Dalton was a great guy, but more or less a footnote in scientific history. Did you know he obsessively collected weather data every day? Rutheford, Mendelev, or even Boltzmann would have been better choice as defender of the atomic model. But we woudln't expect slashdot editors to know the difference, would we?
Physicists not only know everything, but they know everything better. Chemistry is just applied physics.
Energy CAN be destroyed or created (as you pointed out, converted to matter). What you're probably trying to say is that the TOTAL energy of the universe has to be conserved (and that includes the rest energy from matter).
I bet you heard the "energy can't be destroyed or created" line from a chemistry class -- in that context it's a very good approximation.
For the series 1/2 + 1/2 + 1/2..., let's apply the ratio test again:
Asub(n+1) = (n+1)1/2
Asub(n) = (n)1/2
lim n->infinity of Abs(Asub(n+1)/Asub(n)) > 1, therefore the series diverges, as expected.
In Zeno, all the infinitesimally small "halves" eventually add up to a real number, because the series converges. There is no mathematical paradox, only a human one.
Interpretation is a very tricky thing. For example, Maxwell equations are mathematically solid, yet Maxwell himself believed in the existance aether until the day he died. The Aether of course, doesn't exist physically, and doesn't exist mathematically -- it was a created by falty human interpretation. Not even the great Maxwell was immune to it.
then the runner will have to transverse an infinite number of slices to get to his destination, which is impossible
As the other repliers have pointed out, this statement is wrong in the Zeno case. A sum of inifinite series can either converge or diverge. In the Zeno case, the geometric series 1/2^n as n->infinity converges* (thus it doesn't go to infinity to become a paradox in the first place). No fancy new physics is or EVER was necessary to resolve the Zeno paradox, only simple calculus.
As with the aether, there is no paradox in the mathematics. The paradox only appears in the (incorrect) human interpretation based on (incorrect) intuition. Galileo said "Without the help of [Mathematics] it is impossible to conceive a single word of it, and without which one wander in vain through a dark labyrinth."
*By the ratio test, the limit of the absolute value of Asub(n+1)/Asub(n) is 1/2. Since 1/2 is less than 1, the series converges. See Mathematical Methods in the Physical Sciences, Boas, page 12.
Slashdot Mirror
You don't seem to realize the delicious irony of the situation yet. :)
But back to your point. Our Brazillian friend has been in the USA for 2+ years now, and hence is using the term "social networking" so he can get the point across to the english-speaking audience.
Guess you didn't realize he was writing in english in a vain attempt to communicate a message to you. In the future, I recommend a friendlier demeanor in slashdot discussions. Shouldn't be too hard for an aggressive "social networker" like yourself, right?
Americans need the word "social networking" to describe the concept of .... being friendly? What's wrong with "hanging out", "socialize", "become friends"? You go "network" at a business conference, since "socialize" is a no-no during work hours, right? (No need to reply, purely rhetorical).
You know what? Brazillians don't make such distinction. Portuguese doesn't even have a word for our concept of "social networking", as far as I know. I think someone needs to go do some traveling...
And one last thing, are you telling me that at no point in your life were your friends actually strangers to you? If you're never nice to strangers, how the heck did you ever make friends in a new setting? (rhetorical)
irrelevant how many Brazilians I know. character_assassin, you simply don't know what you're talking about because I highly doubt that you personally know any brazillians. I've lived in Brazil and in the US for over a decade (each), and yet, I'm not a native of either country. I can tell you objectively that, on average, there is a much higher probability of a random brazillian national being friendly to you off the streets of Sao Paulo (the "wall-street" financial center of Brazil), than of a random american being friendly to you in New York City. For instance, a Kitty Genovese type of incident would be completely out of character for Sao Paulo . In NYC, such apathy is almost expected. So yes, brazillians ARE more gregarious than americans. More friendly not only towards each other, but also towards strangers.
PP. Obrigado!
Of course they can produce single photons. You must have missed that issue of Physical Review Letters (only the most pretigious journal of physics), here's a copy of the article:
Deterministic Single-Photon Source for Distributed Quantum Networking
PS: Note the "deterministic" part.
The original poster's comment about the effect of gravity was... ahem, cryptic. I think this is what what he meant:
A rocket 50 meters tall will traverse a distance of 4.9 meters in 1 second, assuming it starts from rest and accelerates at 9.8 m/s^2 (we're assuming the rocket's upwards acceleration is just enough to match gravity). Thus, the distance covered is only about 10% of the total rocket length.
Imagine you're watching a movie. The natural inclination of the videographer is to make the rocket fit the frame height exactly. After 1 second, you see 10% of the rocket move off-screen (the camera is in fixed position).
If a mini rocket is only 5 meters tall, it traverse the same distance (4.9 meters) in the same time (1 second), given the same upwards acceleration of 9.8 m/s^2. Thus the distance traveled is total length of the rocket (5m).
If the videographer was filming this, he'd still zoom in so the 5 meter rocket would fit the vertical frame size exactly. But now, from your point of view, the movie-viewer, after 1 second the whole rocket is off-screen!
In essence, the physics are similar, but the intended effect is not. One can't just scale down everything by a factor of x, since the equations are non-linear. We can fix our mini-rocket by making it accelerate slower, but that'd change the thrust equations since gravity is still 9.8 m/s^2 at this scale!
So yes, gravity 'effect' will be different, but yes, the physics are still the same!
Dalton (a chemist) proposed this atomic theory in 1803. 'Chemists' of the time were convinced, but the real scientists, physicists, weren't. In 1906 Boltzmann (a physicist) committed suicide because his theories, based on the atomic postulate, were not well-received. During a physics conference at the turn of the century, he was the only one to defend the atomic model. Other physicists of the time simply didn't buy it. in 1914 Rutheford (a physicist) finally verified experimentally the structure of the atom in a series of scattering experiments. One can't argue with experimental data. Physicists were finally convinced. (The folly of chemists can be demonstrated even today: ask them about their beloved Convervation of Mass 'law'). Dalton was a great guy, but more or less a footnote in scientific history. Did you know he obsessively collected weather data every day? Rutheford, Mendelev, or even Boltzmann would have been better choice as defender of the atomic model. But we woudln't expect slashdot editors to know the difference, would we? Physicists not only know everything, but they know everything better. Chemistry is just applied physics.
Energy CAN be destroyed or created (as you pointed out, converted to matter). What you're probably trying to say is that the TOTAL energy of the universe has to be conserved (and that includes the rest energy from matter).
I bet you heard the "energy can't be destroyed or created" line from a chemistry class -- in that context it's a very good approximation.
Asub(n+1) = (n+1)1/2
Asub(n) = (n)1/2
lim n->infinity of Abs(Asub(n+1)/Asub(n)) > 1, therefore the series diverges, as expected.
In Zeno, all the infinitesimally small "halves" eventually add up to a real number, because the series converges. There is no mathematical paradox, only a human one.
Interpretation is a very tricky thing. For example, Maxwell equations are mathematically solid, yet Maxwell himself believed in the existance aether until the day he died. The Aether of course, doesn't exist physically, and doesn't exist mathematically -- it was a created by falty human interpretation. Not even the great Maxwell was immune to it.
then the runner will have to transverse an infinite number of slices to get to his destination, which is impossible
As the other repliers have pointed out, this statement is wrong in the Zeno case. A sum of inifinite series can either converge or diverge. In the Zeno case, the geometric series 1/2^n as n->infinity converges* (thus it doesn't go to infinity to become a paradox in the first place). No fancy new physics is or EVER was necessary to resolve the Zeno paradox, only simple calculus. As with the aether, there is no paradox in the mathematics. The paradox only appears in the (incorrect) human interpretation based on (incorrect) intuition. Galileo said "Without the help of [Mathematics] it is impossible to conceive a single word of it, and without which one wander in vain through a dark labyrinth." *By the ratio test, the limit of the absolute value of Asub(n+1)/Asub(n) is 1/2. Since 1/2 is less than 1, the series converges. See Mathematical Methods in the Physical Sciences, Boas, page 12.
Nice metaphors. I'd like to hear more. What is your email?
"Dr. Watson, will you please comment a little on the role and contributions of Dr. Rosalind Franklin in the discovery of the structure of the DNA?"