5 ms·
A "vector pointing at Alpha Centauri" is an incomplete definition, since a vector has a magnitude and direction. Also, Alpha Centauri has a declination of –60°
by chicob 7y ago
A "vector pointing at Alpha Centauri" is an incomplete definition, since a vector has a magnitude and direction. Also, Alpha Centauri has a declination of –60° 50′ 02.3737″, which makes it necessary to adjust for the time of the day. That would make people dizzy, which is unfortunate.
So I propose the following very simple definition:
Up - The direction defined by the position vector of Polaris with reference to the center of the Earth (not to be confused with North).
Down - The direction opposite of Up (See also: South).
- munificent 7y ago> since a vector has a magnitude and direction. How is the direction represented?
- archgoon 7y agoA normalized vector; i.e. a vector with magnitude 1.
- saalweachter 7y agoThis does give us the opportunity for international compromise. Since GMT is the time in England, and the meter is (more or less) 3 Parisian feet, we should at least standardize "up" as the direction the Empire State Building goes.