Warning: SPOILERS for Star Trek: Discovery Season 4, Episode 10 - "The Galactic Barrier"
The USS Discovery has crossed through the Galactic Barrier and Star Trek: Discovery updated how Star Trek: The Original Series depicted boldly going into the final frontier to a new galaxy. After Dr. Ruon Tarka (Shawn Doyle) destroyed the Dark Matter Anomaly, a second DMA quickly appeared. The United Federation of Planets needed an immediate diplomatic response to this disastrous First Contact so Captain Michael Burnham (Sonequa Martin-Green) and the Discovery were assigned the mission to cross the Galactic Barrier and make peace with Species 10C.
The Galatic Barrier is a rim of negative energy that surrounds the Milky Way Galaxy and Star Trek has never canonically depicted what lies beyond it before, although aliens and technology have crossed into the Alpha Quadrant from outside the galaxy. The 23rd-century Starship Enterprise commanded by Captain James T. Kirk (William Shatner) entered the Galactic Barrier three times in TOS and survived, although the negative energy caused all manner of damage to the starship and its shields. In Star Trek: TOS' second pilot, "Where No Man Has Gone Before," entering the Galactic Barrier affected several crewmembers with high ESP ratings and gave Lt. Gary Mitchell (Gary Lockwood) and Dr. Elizabeth Dehner (Sally Kellerman) godlike psychic powers. In the TOS season 3 episode, "Is There No Truth In Beauty," the Enterprise was hijacked and became stranded in a space-time continuum void inside the Galactic Barrier.
In Star Trek: Discovery, the USS Discovery couldn't use its spore displacement hub drive to jump past the Galactic Barrier because the mycelial network thins out the closer it gets to the negative energy wall. Thus, Discovery had to cross the Barrier using standard warp travel. In spite of upgrading Discovery's shields with 32nd-century negative programmable matter technology, which Dr. Tarka and Cleveland Booker (David Ajala) also had to acquire a supply of for their ship, the Galactic Barrier's energy could still destroy the Discovery within minutes. Commander Paul Stamets (Anthony Rapp) hit upon an ingenious solution for Discovery to enter spatial cells, which are bubbles within the border of the galaxy that can protect the starship from negative energy. Discovery could then ride the bubbles safely through the Galactic Barrier.
Each time Star Trek: TOS depicted the Enterprise passing through the Galactic Barrier was different, which gave Star Trek: Discovery leeway in creating new challenges Captain Burnham's starship during its voyage through the energy wall. It's worth remembering that Kirk's Enterprise passed through different sections of the Galactic Barrier than Discovery did and the edge of the galaxy's conditions differ across its span. Unfortunately, as Mr. Saru (Doug Jones) reported, the density of negative particles in the sector of the Barrier Discovery passed through was significantly higher than Kirk encountered, which placed Burnham's ship in greater danger. But one cool innovation by Star Trek: Discovery was the shift in visible spectrum Discovery experienced so that color bled out of the crew's (and the audience's) eyesight.
Despite the USS Discovery being almost a thousand years more advanced and powerful than the 23rd-century Starship Enterprise, the area of the Galactic Barrier Discovery needed to breach to reach Species 10C was a completely different and more dangerous experience than what was shown in TOS. Star Trek: Discovery also enhanced the look and design of the Galactic Barrier from the pinkish haze shown in the 1960s' Star Trek. But one big difference so far of Star Trek going where no one has gone before is that Captain Kirk's Enterprise always successfully returned to the Milky Way after crossing the Galactic Barrier. In Star Trek: Discovery season 4, there's no telling yet who or what Captain Burnham and her crew will encounter in the new galaxy and whether the USS Discovery will be able to safely cross the Galactic Barrier again to return home.
Star Trek: Discovery Season 4 streams Thursdays on Paramount+.
