In Greek mythology Chiron is a centaur, in fact the most educated and civilised member of that race. He is a healer, a herbalist and a wise mentor to men. He is famous for having been accidentally shot by Heracles' (Hercules) poison arrows, and for suffering constantly because as an immortal god he could not die. With Zeus' intercession Chiron gave up his immortality to Prometheus, who was chained to a rock. So Chiron was allowed to die rather than suffer for eternity, and Zeus placed him in the sky as the constellation Sagittarius (some sources say Centaurus).
Chiron the asteroid was discovered in 1977. It was soon realised that Chiron is in fact part icy comet, part rocky asteriod that travels between the orbits of Saturn and Uranus.
Chiron's physical makeup is a big clue to his function in astrology. Many astrologers feel that Chiron partakes of the energies of both Uranus and Saturn; the icy part ~ and his erratic orbit! ~ represent his connection to the cosmic energies of Uranus, and the rocky, materialistic part to the energies of Saturn.
I believe Chiron has a major role to play in helping humankind to enter the Age of Aquarius. Many people in the "new age" community believe the Age of Aquarius heralds a new era of relations between humans, and with humans to the heavens. The trick is that Uranus and Aquarius represent having access to cosmic wisdom which could help facilitate this change; but Saturn represents the existing forms we all struggle with, the status quo that's been in place for so long, the things we see around us that depress us and make us pessimistic about the future.
The good news is that a change IS due, and we can all play our part in this. Chiron in the birth chart can help you see where you can channel the cosmic wisdom into an acceptable form in your life. Chiron, as the mediator between Mind and Matter, can help us to transform our ideas into reality.
For example, this blog is one attempt at activating my own Chiron. I have Chiron in the 5th house, which is creative expression, and in Aries, which is indepedence and assertion. By having this forum for my desire for creative expression, I am doing something to satisfy my need to transform my life.
Chiron is associated with healing, and by activating our Chiron we can begin the work of self healing.