"Sun rises in the east" we say, but when we are outside the solar system where's the east?

Answer by  TMATM (499)

When refering to directions or the location of objects in space, the equatorial coordinate system is used. Imagine space as a globe with grid lines similar to longitude and latitude on earth. On this grid, Right ascension defines your east/west directions, just like longitude. Declination is your north/south direction like latitude.

Answer by  kevincai96 (669)

There is no directions in space, since cardinal directions are relative. Without anything to compare to, there is no relativity, and thus no direction. So east could be a five o' clock region from earth if you were in Florida, and it could be an 11 o' clock region is another country. The key word is relativity.