Parsec
- Thread starter Photon
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The only time I remember it offhand was in Tin Man cause I saw it in the last few months. I forget exactly when but it may have had to do with the E-Ds distance from the Gomtu.
RAMA
I am certain it was used in 'Voyager', repeatedly.
Yes it's definitely in Voyager, and I'm pretty sure it's in DS9. It's a real world measurement term that's not uncommon, so I'd expect it to be well used in Trek.
A Google search of Chakoteya's site containing transcripts of all Star Trek episodes and movies turns up uses of "parsec" or "parsecs" in 6 TOS episodes, 5 TNG, 12 VGR, and 1 ENT.
So is "light-year", come to think of it.
Hm, true.
Um, so are all units of measure we know of.
There's always the Galactic Year, but having to express every time element within the realm of human experience in scientific notation would be kind of a bitch.
Light-year is defined in terms of the time it takes the Earth to complete an orbit around the Sun. A parsec is defined in terms of the distance from the Earth to the Sun. These are Earth-derived units of measure.
Other units of measure are more universal: the charge of an electron, the mass of a proton, the radius of the lowest-energy electron orbit, the characteristic frequency of a hydrogen atom, etc. A politically correct galactic federation might want to use units of measurement defined in terms of such universal constants.
We don't use the teeny weeny charge of an electron as a unit of measure, tho - we measure charge via "coulomb", a unit that is defined (among other things, and via our definition the current unit "ampere") through our choice of "meter" for length. And "meter" is another of those extremely Earth-centric things, originally supposed to represent one 10,000,000th of the distance between Earth's pole and equator.
We do have a more modern, competing definition of ampere that utilizes the charge of the electron, but the point is that the magnitude of one ampere is still determined by the older definition where nice, round, Earth-centric units were used; it just happens to be modernized into featuring 6.241x10^18 electron charges, a nonsensical figure as such.
And that permeates through every unit we use in practice, some of the weirder whitecoats exempted. We don't really see evidence that our heroes would have gotten rid of the SI unit system, with its Earth-centric kilograms and watts and the like. Except when they slip back to even more Earth-centric things such as atmospheres and hours...
Timo Saloniemi
We do have a more modern, competing definition of ampere that utilizes the charge of the electron, but the point is that the magnitude of one ampere is still determined by the older definition where nice, round, Earth-centric units were used; it just happens to be modernized into featuring 6.241x10^18 electron charges, a nonsensical figure as such.
And that permeates through every unit we use in practice, some of the weirder whitecoats exempted. We don't really see evidence that our heroes would have gotten rid of the SI unit system, with its Earth-centric kilograms and watts and the like. Except when they slip back to even more Earth-centric things such as atmospheres and hours...
Timo Saloniemi
Those are values, not units. The unit of measure for the mass of a proton, for example, is grams, which of course is based on Earth-stuff.
The proton's mass is also expressed as 1.0072766 u, where u is the atomic mass unit, defined as 1/12 the mass of a carbon-12 atom. Which isn't an Earth-centric unit, though it could be seen as representing a chauvinism in favor of carbon-based life forms.
The Horta would be up in arms about that - if it had any arms, that is.
So is a light year shorter in a leap year?
I thought that was an AU. Looking it up a parsec is ~3.26ly.
A parsec (short for parallax second) is the distance at which the Earth's orbital radius (1 AU) would appear to subtend an angle of one second of arc. Its definition stems from observations of nearby stars that appear to move against a background of distant stars as the Earth orbits the Sun. Simple trigonometry shows that a parsec is therefore just over 200,000 AU. One second of arc is approximately 1/1800 of the diameter of the Moon in our sky so that should give you an idea of the precision of measurement that is required to observe such parallax motion, given that all the nearest stars are more distant than 1 parsec.
http://en.wikipedia.org/wiki/Parsec
http://en.wikipedia.org/wiki/Parsec
Thank you. I know I will sleep better tonight knowing that.
Yeah, the sky'll be a long time falling.
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