Well that sounds like it refers to the dark lane which spearates the larger Orion Nebula (M42) from a smaller area called de Mairan's Nebula (M43). I think this is the area that has been referred to as "Orion's Gate".
There are some fringe Christian groups that give a religious significance to this region. Example: http://www.orionsgate.org/
The following nicknames are the ones that I'm familiar with regarding the Orion Nebula:
"M42 itself is apparently a very turbulent cloud of gas and dust, full of interesting details, which Charles Robert O'Dell has compared to the rich topography of the Grand Canyon in his HST photo caption. The major features got names on their own by various observers: The dark nebula forming the lane separating M43 from the main nebula extends well into the latter, forming a feature generally nicknamed the "Fish's Mouth". The bright regions to both sides are called the "wings", while at the end of the Fish's Mouth there's a cluster of newly formed stars, called the "Trapezium cluster". The wing extension to the south on the east (lower left in our image) is called "The Sword", the bright nebulosity below the Trapezium "The Thrust" and the fainter western (right) extension "The Sail"."
Sic itur ad astra!
Chance favors the prepared mind.
A man is a small thing, and the night is very large and full of wonders.
The term "Orion's Gate" is used not by astronomers (as far as I know) but by certain non-scientific groups (see link above).
Etni was asking about a term she found in Finnish so perhaps it is more commonly known in Scandanavia. Or, the original screenwriter may have been aware of these fringe groups.
Thanks to you too for answering, DaveMitsky!
I don't think the term "Orion's Gate" is more commonly known in scandinavia; I found only 1 google result for the Finnish term, which is the reason I had to start asking around how to translate it. But you're right, the screenwriter is familiar with the non-scientific astronomy of these christian groups, and I believe the place is mentioned in the script because of its spiritual meaning to those people.
Well, now I know what I should call it, no matter whether I'm talking to religious or scientific people ;)
Never wrote:Never heard the term and it doesn't sound very astronomy-like./Jake
You're right :) It's explained in Stargazer's post (the fourth one in this thread)