What's up with the ninth chevron?

[Nate the Great]

This is a Stargate thread. It's not a 5MSG thread, so it belongs here. As part of another thread I was reminded of the existence of a ninth chevron, and the possiblities of a nine-glyph address. Here's where we share our personal theories about what it does.

For me, they sort of break down into:
1. Since the eighth is an intergalactic area code, the ninth must relate to other dimensions, perhaps even the realm of Ascended beings.
2. A Stargate really can travel to other time periods through the use of nine-glyph addresses.
3. Perhaps with enough power and enough pinpoint accuracy through the use of a ninth coordiate, a Stargate can create a spontaneous, one-ended wormhole. You wouldn't be able to return, but...
4. A ninth glyph and more power can create a two-way wormhole.

Opinions?