# Coordinates and firections ## General directions in space: North and south are in the same general direction as on Earth, but perpendicular to Earth's orbit (and not in the axis of Earth's rotation.) West and East, based on the [[Worlds Trade Centers|WTC]] of the same names. Down is toward the Sun and up is outward of the [[Solar System]]. ## Conventions on coordinates in the [[Solar System]] x axis: From the Sun towards Sagittarius A\*, based on their relative position at 12000-01-01 00:00:00;000. Positive towards the outside of the Milky Way. y axis: perpendicular to the orbital plane of Earth, in the same approximate direction as Earth's North. Positive towards the North. z axis: perpendicular to the two previous axes. Positive in the vector product of $\bar{i} \times \bar{j}$ direction. Origin: the center of mass of the Sun.