1000

A light-year is equal to:
The figures above are based on a Julian year (not Gregorian year) of exactly 365.25 days (each of exactly 86,400 SI seconds, totalling 31,557,600 seconds)[2] and a defined speed of light of 299,792,458 m/s, both included in the IAU (1976) System of Astronomical Constants, used since 1984.[3] The DE405 value of the astronomical unit, 149,597,870,691 m,[4] is used for the light-year in astronomical units and parsecs.


http://en.wikipedia.org/wiki/Light_year
 
Inkara1 said:
A light-year is equal to:
The figures above are based on a Julian year (not Gregorian year) of exactly 365.25 days (each of exactly 86,400 SI seconds, totalling 31,557,600 seconds)[2] and a defined speed of light of 299,792,458 m/s, both included in the IAU (1976) System of Astronomical Constants, used since 1984.[3] The DE405 value of the astronomical unit, 149,597,870,691 m,[4] is used for the light-year in astronomical units and parsecs.


http://en.wikipedia.org/wiki/Light_year
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I am assuming that you looked that up, and on top of that Copy, and Pasted, how dare you. JK... i am sure if Altron saw my question he would do the math.
 
GrandCaravanSE said:
I am assuming that you looked that up, and on top of that Copy, and Pasted, how dare you. JK... i am sure if Altron saw my question he would do the math.
Click to expand...

well, simple dimensional analysis will tell you,

just going offhand (from my mental handbook of scientific constants)
1 ly = 1 (yr) * 2.99 * 10^8 (m/s) * 1/1000 (km/m) * 1/1.61 (mi/km) * 60 (s/min) * 60 (min/hr) * 24 (hr/day) * 365.25 (day/yr) = 5,870,000,000,000 mi

or if you prefer, I can express "c" as 1/sqrt(ue) or 1/sqrt(4pi*10^-7 * 8.85*10^-12)

Frankly, I find fault with a measurement system based on the orbit of one planet around one sun, which may fluctuate over millions of years during the star's lifecycle
 
Altron said:
well, simple dimensional analysis will tell you,

just going offhand (from my mental handbook of scientific constants)
1 ly = 1 (yr) * 2.99 * 10^8 (m/s) * 1/1000 (km/m) * 1/1.61 (mi/km) * 60 (s/min) * 60 (min/hr) * 24 (hr/day) * 365.25 (day/yr) = 5,870,000,000,000 mi

or if you prefer, I can express "c" as 1/sqrt(ue) or 1/sqrt(4pi*10^-7 * 8.85*10^-12)

Frankly, I find fault with a measurement system based on the orbit of one planet around one sun, which may fluctuate over millions of years during the star's lifecycle
Click to expand...

Now that is what i was looking for, very nice, how were all your tests?
 
well, I had to do a project on mode-locking lasers. show that the superposition of sine waves with frequencies that are integer multiples of each other becomes a pulse train model as the number of waves increases. fucken destroyed that shit.

then i had to do some optics. one or two simple geometrical optics problems, then 3 or 4 simple physical optics problems. diffraction, diffusion, lenses, all that fun stuff.

then of course mechanics. lagrange and hamiltons equations. here's one of the problems:
you have a rod with a spring on it, and a mass hanging on the end of the spring. describe the motion.
I got a 76 on that (woohoo!) of course the three or four newly imported chinese grad students destroyed the curve, but I made it.

then a paper on public opinion and political efficacy, and some other junk

next on the chopping block for the spring - intermediate waves and optics, electromagnetism, and astrophysics.
 
Altron said:
well, I had to do a project on mode-locking lasers. show that the superposition of sine waves with frequencies that are integer multiples of each other becomes a pulse train model as the number of waves increases. fucken destroyed that shit.

then i had to do some optics. one or two simple geometrical optics problems, then 3 or 4 simple physical optics problems. diffraction, diffusion, lenses, all that fun stuff.

then of course mechanics. lagrange and hamiltons equations. here's one of the problems:
you have a rod with a spring on it, and a mass hanging on the end of the spring. describe the motion.
I got a 76 on that (woohoo!) of course the three or four newly imported chinese grad students destroyed the curve, but I made it.

then a paper on public opinion and political efficacy, and some other junk

next on the chopping block for the spring - intermediate waves and optics, electromagnetism, and astrophysics.
Click to expand...

Damn chinese, i still rember when i used to bitch in highschool at a problem that took more than 5 min to do, and my teacher said "When your in college a problem that takes up a full page and takes 20 min will be short".
 
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