Scientists trying to open portal

They didn't explain the science behind it very well. Why do they think it is a mirror of this world. It could just be another dimension. can anyone dumb this down for me? Scientists making life altering decisions without the consent of the people is always a worry. They don't seem to care.
 
And what if they can't close the door?
the dynamics/balance in the other thread you posted is of more concern to me actually. the yin and yang is the balance of all that is chaos...... if reversed (or something like the this, the opening of doorways, mirror worlds, etc..) what is the repercussions of that balance?... for every action there is an equal reaction, blah, blah, blah, kinda stuff, but is no longer heeded..... nature, the world, the universe, time, is a finely balanced machine, the slightest wobble throws everything into an uncontrollable spin that compounds with every ripple...... we are playing with things we have no knowledge of or what the long term effects will be......