I do not believe it to be be either an alternative timeline nor some warped quantum reality.
It most resembles the evil universe that Lazarus was from in TOS. Except that universe required your opposite to be alive at the same time you were and many people are dead in their counterpart reality in the Light/Dark schema.
Could the mirror universe be some sort of man made reality in the same way Wesley created the very real but flawed "remember me" warp bubble universe?
I originally thought that the original dark universe was created by the Enterprise crew and again independently by the DS9 crew. DS9 had historical records and knowledge of the past event so their universe filled in the facts of this previous encounter.
The problem is that mirror universe seems to operate indepently of ours and they created transporter technology to come here.
A Mirror Darkly need not enter into the discussion because using Nu Trek defintions that is both an alternate timeline and an alterate universe.
It most resembles the evil universe that Lazarus was from in TOS. Except that universe required your opposite to be alive at the same time you were and many people are dead in their counterpart reality in the Light/Dark schema.
Could the mirror universe be some sort of man made reality in the same way Wesley created the very real but flawed "remember me" warp bubble universe?
I originally thought that the original dark universe was created by the Enterprise crew and again independently by the DS9 crew. DS9 had historical records and knowledge of the past event so their universe filled in the facts of this previous encounter.
The problem is that mirror universe seems to operate indepently of ours and they created transporter technology to come here.
A Mirror Darkly need not enter into the discussion because using Nu Trek defintions that is both an alternate timeline and an alterate universe.