Since we're talking about astronomy, both imperial and metric units are "wrong" and domain specific units should be used instead.
Unit of length should be astronomical units (abbrev. au, formerly AU), the mean distance between earth and the sun. If talking about distances in stellar scale, it should be parsec ("parallax second"), the distance from which an 1 au object can be seen at 1 arc second apparent size (and sin x = x is assumed because x is small).
Unit of mass is usually solar masses. In some special cases earth masses or jupiter masses.
Unit of density is either number of atoms in m^3 or other big volume when talking about interstellar medium or kg/m^3 when talking about planets or stars.
Unit of time is usually measured in years.
When you use solar masses, years and astronomical units, Kepler's 3rd law is reduced to: (m1+m2)period^2 = semi-major-axis^3 and the gravitational constant G = 4 * pi^2 (and thus it's cancelled out from G(m1+m2) * P^2 = 4 * pi^2 * a^3).
I definitely would have liked to see the distance in astronomical units and a verbal description of the distance ie. (5 million kilometers, not 5000000 km). Humans are really bad at understanding big numbers, any means of helping to understand that would be useful.
Unit of length should be astronomical units (abbrev. au, formerly AU), the mean distance between earth and the sun. If talking about distances in stellar scale, it should be parsec ("parallax second"), the distance from which an 1 au object can be seen at 1 arc second apparent size (and sin x = x is assumed because x is small).
Unit of mass is usually solar masses. In some special cases earth masses or jupiter masses.
Unit of density is either number of atoms in m^3 or other big volume when talking about interstellar medium or kg/m^3 when talking about planets or stars.
Unit of time is usually measured in years.
When you use solar masses, years and astronomical units, Kepler's 3rd law is reduced to: (m1+m2)period^2 = semi-major-axis^3 and the gravitational constant G = 4 * pi^2 (and thus it's cancelled out from G(m1+m2) * P^2 = 4 * pi^2 * a^3).
I definitely would have liked to see the distance in astronomical units and a verbal description of the distance ie. (5 million kilometers, not 5000000 km). Humans are really bad at understanding big numbers, any means of helping to understand that would be useful.