Elemental Plane lore question

[RoughJustice]

So i was reading up on some of the info on the elemental plane, and im completely confused about where in the universe this actually is. the way i imagine it is its like the core of azeroth, like the core of the earth is just a big ball of lava... but i feel like thats wrong, wouldnt surprise me. its said that water from the water plane drips down into the earth plane, but steam from the fire plane gets into the water plane... or things from the surfice of azeroth falls into one of them. It's just so confusing so where exactly are the planes?

[Golden Yak]

It's not really a physical location that you can get to just by traveling normally - it's a separate dimension that exists alongside Azeroth, though it's described as being within, a part of Azeroth. It's sort've like the Emerald Dream. It might not even be a planet like Azeroth, but different elemental landscapes that merge and join with one another.

When Deathwing broke down the barrier between Azeroth and the elemental plane, parts of the plane started to overlap and merge with Azeroth - that's why the Firelands is growing up out of Mount Hyjal and Skywall is appearing in the clouds over Uldum.

More info here: http://www.wowpedia.org/Elemental_plane