Quote:
Originally Posted by murraypaul
I'm not sure I've ever seen parsec used in science-fiction, and if it is used at all, its used is overwhelmed by the use of light-years. In reality, both light-years and parsec are used.
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So what point were you trying to make here:
Quote:
Originally Posted by murraypaul
Nor are lightyears, which is why they are used more in science fiction than in reality. The parsec is the preferred unit.
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Were you trying to say that since parsec it used in reality, although far less than lightyear, it is almost never used in fiction so that makes it better?
Quote:
Originally Posted by murraypaul
The parsec was defined based on a calculation of a parallex of 1 arc second at the distance of the sun, but that has nothing to do with the measurement of the distance between two objects, and you don't measure parallex to calculate that distance. In the same way that the kilo was defined as the mass of 1 litre of water, but you don't measure people's weight by comparing them to volumes of water.
A parsec is a distance of 30.857×10^12 km.
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You do measure parallex, I quoted the text that explained that. Maybe you would be more comfortable with an explanation that involved drawings:
http://www.astronomy.ohio-state.edu/...distances.html