- An ion (/ˈaɪ.ɒn, -ən/) is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by convention. The net charge of an ion is not zero because its total number of electrons is unequal to its total number of protons.
- Gacrux (stars.astro.illinois.edu)
GACRUX (Gamma Crucis). In our “western” star lore, the stars with proper names come from the set that could be seen from the lands of the ancient middle east and Arabia, and do not include those of the far southern hemisphere, which is largely invisible below the horizon from northern lands. Yet those who needed the stars to find their way, the old navigators, also needed quick names for some of the stars and just made them up. “Gacrux” is a prime example of such a star, its name deriving strictly from its Greek letter name, Gamma Crucis, the third-brightest star in the constellation Crux, the Southern Cross.