'ach HoD, Hevetlh wIghoSchugh veH tIn wI'el maH'e'!
But Captain, that course will take us into the [Great] Barrier as well! (ST5)

TREK TRIVIA:

The planet QI'tu' at the center of our galaxy is surrounded by the Great Barrier, an immense energy field (HoSchem) which imprisons the God-Being (ST5).

An "enhanced" Barclay took the Enterprise-D to the center of the galaxy to visit the Cytherians 30,000 light years away. A large glowing cloud was visible in the distance, possibly the Great Barrier. (TNG "The Nth Degree")

ASTRONOMY NOTES:

So-called hypervelocity stars have been discovered shooting out of the Milky Way with speeds around one million miles per hour and are thought to have been ejected by interactions with the supermassive black hole in the Galaxy's center.  For an image of the real cloud of antimatter at the center of the Milky Way cf. http://antwrp.gsfc.nasa.gov/apod/ap970501.html 

SEE ALSO:

veH                     boundary,  frontier,  barrier,  border (n)
HeH                     edge, rim (n)
Dop                     side (n)
ghangwI'                horizon (n)
qIbHeS                  galactic rim (n)