Great Barrier The Great Barrier was an immense energy field of unknown properties surrounding the galactic core of the Milky Way Galaxy . As of 2287 , the Barrier was thought to be impassable , as no probe had ever returned . In that year , the became the first known vessel to penetrate the barrier , having been commandeered by the renegade Vulcan Sybok , who was on a quest to discover the mythical planet of . Claiming to have been given a vision by God himself , Sybok mentally manipulated the " Enterprise " crew into approaching the center of the galaxy , believing that God resided on Sha Ka Ree on the other side . Although Captain Kirk believed that the " Enterprise " would be destroyed in the attempt , Sybok maintained that the danger posed by the Barrier was simply an illusion , an expression of the universal fear of the unknown . Sybok was ultimately proven correct when the ship passed through with no ill effects . In addition , the " Enterprise " encountered a planet on the other side of the Barrier , seemingly confirming Sybok ' s vision . A malevolent alien entity was found on the planet , imprisoned by the Barrier . It impersonated the God Sybok was expecting to find in an attempt to manipulate Sybok into providing it with a starship with which it could escape . Upon discovery of this fact , Sybok attempted to oppose the entity , as the " Enterprise " crew fired on its location with photon torpedo es . Although this resulted in the death of Sybok , the alien entity survived . The entity was also assaulted with disruptor cannon fire by a Klingon Bird - of - Prey , which had pursued the " Enterprise " through the Barrier . ( ) Background information . The Great Barrier , and the planet within , would seem to have appeared only at most eighteen years prior to 2287 . In the episode , the explored the center of the galaxy . At that time the center was discovered to be a point between dimensions surrounded by a matter - energy whirlwind . Presumably the point between dimension had disappeared since no one expected to find it eighteen years later . There also presumably was no Great Barrier back in 2269 , since the " Enterprise " would have had to have crossed it . The fact that the Barrier and center of the galaxy were only some 6 . 7 hours away from Nimbus III , in the Neutral Zone , at warp 7 is somewhat inconsistent with how fast the warp speeds have been established to be later on in " Star Trek " after . In " " ( p . 11 ) , the Great Barrier is depicted as a spherical energy field engulfing the whole galactic core and all the stars within . The diameter of the Great Barrier is approximately 15 , 000 light year s . The planet encountered in " Star Trek V : The Final Frontier " is not depicted to be at the center of the galaxy . Instead , it is at the outer edges of the energy field , some 7 , 000 light years away from the center . The point between dimensions , where the crew traveled to in " The Magicks of Megas - Tu " , is labeled as a massive black hole called Sagittarius A at the center of the galaxy . This location for the planet would be inconsistent with the movie , but makes it possible for both accounts of the center of the galaxy to coexist , though Sagittarius A * ( pronounced " A - star " , as it was called in the real world ) , a supermassive black hole , was not compatible with the creation point phenomenon that was seen in " The Magicks of Megas - Tu " . The galactic barrier is connected to the Great Barrier . The Great Barrier is stated to be a related , but distinct energy field . Apocrypha . According to the novel " Q - Strike " , The Great Barrier was created 500 , 000 years ago by the Q Continuum to imprison the malevolent entity known as The One to the planet for its crimes . According to the same novel , it was created to protect the Milky Way from 0 ( Zero ) , one of the Q Continuum characters