ooh good question.

i've always treated it as a "Sentient and Malicious Equals Sign" in my mind. The Gate is an evil bastard that likes to make people pay too much to pass through. Amestris = Earth, where the '=' is the Gate and the Gate is out to screw both sides as much as possible.

But beyond that..... no idea : x sowwy. good question tho.

It's interesting in the episode where he drops into his body on this side of the gate. the death on this side of the gate powers the alchemy on their side of the gate... but also remember that while it was 1921 where Ed landed, he had seen the atomic weapons at the end of WWII and his father had pointed that out to him. Ed had seen all the horror that our twentieth century was to bring forth; the barbarism that is inherent in human beings and the cool, efficiency that automation brings to meating out death...

The existence of the stone was brought forth by the violent seizure of life... for to gain, there must be loss...

There was all this violent loss of life here, in our twentiethcentury, and for what? What happened to all that life that was lost so young? It's in the Gate. A capacitor. It stores this charge... this charge of energy that was the life lost tragically on the fields of battle across the whole face of the earth.

And the sin of the Ishbalans on their side of the Gate? Perhaps it was the technological step towards exploiting that energy... instead of the one we took on this side of the gate that gave us...

Yes. A capacitor. You mention parallel universes then you're aware that in quantum physics and secular humanism things get really fuzzy...

So lets give a hypothetical equivalent to the useful energy contained in one human soul...

what would it look like?

what would be the physical forces that could contain a plethora of this, this... and then you discover how to unlock this energy...and then you do... and there are the consequences...

I'm terribly sorry about that! I really got carried away. I'm sitting here getting into the mind of the writer. For me the biggest clue to everything in the series Ed's conversation with his father. He explained what was inside the Gate and that it wished only to get out.

Well, I know in the manga that Ed saw two doors in his attempt to get out of Gluttony's stomach. Then again, the Gate is an entirely different thing in the manga so that could mean nothing. ^^; Oh, and here's the English tracklist for the 3rd OST. ^_^

1) Brothers
2) Crossroads
3) Pathetic
4) Devotion
5) Optimistic
6) Strategy
7) Regret
8) Advance
9) Victory
10) Fighting Bravely
11) Hope
12) Reminiscence
13) Dancing
14) Traveling in Disguise
15) Suspicion
16) Invasion
17) Control
18) Sorrow
19) Farewell Tune (Piano Version)
20) Oppression
21) Violation
22) Fate
23) Farewell Tune

well first i looked up what wikipedia has to say about the Gate of Alchemy
"The Gate is the source of all alchemic energy, often exemplified by the light of an alchemic transmutation. It bears a striking resemblance to Auguste Rodin's "The Gates of Hell". It is depicted as a large, black, two-doored gate that is variable in height and typically suspended in a white void."

it was said that the gate is within every soul, and does not have an exact location. I guess the gate is like a door to heaven or hell in a way. In the world where alchemy developed, it is used as a source of energy. In our world, the gate is like a version of afterlife, except there's no actually world where the soul can go, but it only desolves into a source of energy.

Could it be that the gate is something like gate of death or something. Because if you to there, even tho you will get alot of knowledge about alchemy, sacrifice is needed, which is really a near death experimence. For people who are taken to the other world, it might be like...well im not sure how to word it, but kinda like given another chance to live. Like they are not suppose to know about the other world. Idk, is a confusin topic

the manga some really different stuffs about the gate...i wanna read it

well....>> << the gate seems to be something like a waitroom or something, a place where dead people go....oh snap! I think I have a theory:
ok, so it's some kind of energy source, everytime you do a transmutation, you use energy from the gate. and the gate takes energy from the other world, human lives, remember the thing dante said? so it's like a power source, maybe heavens or maybe limbo. it's a place where the human soul is transfered to the other side. it's hard to figure it out....hmm, but hohemheim said "the gate is within you", so it has to do something with the soul....I don't know, it's too complex *brain explodes*

oooor maybe it could be the center of everything =D yeah, it's in between the two worlds, the center of equivalent exchange. it's the "all" in "one and all, and all is one", it's the control place. OH MY GOD!
remember in the...er....I thihk the 6th manga, God says "I'm one, I'm all, and I'm YOU". so this also connects to hoho's saying, he has a piece of the "all" in his soul, the gate is within him. aaargh, my brain is gonna explode and this is ay too religious lol. anywho, It's the center of everything, the place where God controls people and the worlds, the place where the souls wander, the bridge between two worlds.

Just out of curiosity . . . anyone read Stephen King's Dark Tower series? The Gate and the Tower seem to be quite similar. Same function as a dimensional doorway, same sense of cruelty . . .

yes and I was thinking much the same thing about the gate and the tower (this theory makes even more sense if you were able to read the last book in the series)

I guess its always about the hope of when the wheel turns next we will find redemption.