Good question. Maybe it IS real.
But let's try and explain it scientifically if we can.
(And science isn't always physics, but also psychology, and biology)
I actually don't have a scientific explanation for it, if it exists at all,
maybe someone else can explain it.
I heard a scientific explanation about how Remote Viewing is possible. And Remote Viewing is like Astral Traveling in a way so they are connected:http://www.youtube.com/watch?v=hm5L8z34sNg
(Agree or disagree with this, at least it is science-based)
EDIT: I just watched it again, and I think he has some good ideas. It gets very scientific, even for me, but I understand it for the most part. I will sum it up for the layman the best I can.
In our world, long radio waves pass through us and shorter ones have no influence either. We live in a world of perceivable light waves and that is the 'middle' for us, give or take. But go an 'octave' higher or lower, and there may be a world that is as real as ours, and our 'middle' waves pass through them just the same. Where is the end of the electro-magnetic spectrum? Does it go on forever, but we simply can't perceive them? Is it an endless continuum? Evolution has engineered our minds to see the present, here and now, so we can survive, and perceive the proverbial oncoming tiger, and not see those other dimensional beings. But in a certain state of mind... theta wave, or even others, perhaps we CAN perceive these other 'realities'.
(I am just summing up the video link as best I can in case others don't want to view it. So don't blame ME if you disagree. But it does make you think.......