One of my many interests is Astrology. This is not, as most people seem to assume, simply a case of slotting people into 1 of 12 labels, but is actually a lot more complicated.
The basic premise is, is that the planetary bodies that we share this part of the universe with exert forces upon us from the moment of conception that affect our personality and lives.
Typically what is refered to as Astrology is simply using just one celestial body - the Sun. The Moon, Mars, Venus, Mecury and all the other planets have their own effects too, so rather than it just being one of twelve possible choices, there are over 60,000,000,000 even just taking into account 10 of Earth's neighbours.
It's certainly impossible to deny that they do have any effect - the tides are caused by the Moon for example. If it can cause vast bodies of water to move about, surely it also has some effect on a species that is 70% water.