Pluto, and its placement in the sky is used in astrology to describe the cycle of birth and death, revolution and regeneration. Because Pluto spends a varying (but fairly long) time each sign, the effects are generational rather than societal, or personal. Pluto symbolizes:

The placement of this planet within the zodiac will give an indication as to the nature of the revolution or transformation. Currently, pluto is in sagittarius.

In astrological charts, pluto is symbolized as:


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I can't find any documentation as to what this symbol is supposed to represent, /msg me if you know.