Trans-dimensional disturbance
A trans-dimensional disturbance was an astronomical phenomenon in the Delphic Expanse. These phenomena were created by the Sphere-Builders as a prelude to invasion. The space within the disturbance was reconfigured, gradually at first. Such a disturbance was essentially a convergence of spatial anomalies, which were very common in the Expanse, created by spheres in that region. A trans-dimensional disturbance was also an unusually strong type of gravimetric disturbance and generated gravimetric waves. It contained elevated levels of ammonium sulfide. Usually, inside a developed trans-dimensional disturbance, the atmosphere had an auburn hue and light-smears often appeared in mid-air. Helmsman Travis Mayweather once likened a trans-dimensional disturbance to soup.

Physical effects of exposure 
Unless appropriate precautions were taken, nothing from the prime universe could survive for any substantial time inside a trans-dimensional disturbance.

For example, the reconfigured space within it disrupted the neocortex inside the Human brain. However, a Denobulan was almost entirely immune to the psychological effects of the phenomenon.

Staying inside a trans-dimensional disturbance could cause epidermal decay, causing cracks to appear on a lifeform's skin, though a Denobulan was also immune to this happening. Vulcans were more sensitive to the epidermal decay than Humans were. ()

History 
In December 2153,  encountered a trans-dimensional disturbance which had a diameter of more than seven hundred million kilometers. Located exactly equidistant from five Delphic Expanse spheres, the phenomenon was expanding at a rate of several kilometers per second. It engulfed a once-inhabited planet, some while before Enterprise discovered the phenomenon, and also contained a Sphere-Builder transport pod.

When Enterprise attempted to tow the pod out of it, the disturbance grew even bigger, immersing a large, forward portion of Enterprise (almost a third of the vessel), including the starship's bridge. Sparks that burst out of a console therein didn't dissipate but gradually spread outwards in a slowly spreading cloud. The ship soon managed to break free from the disturbance, though, taking the pod with it. ()

In January 2154, a brand new trans-dimensional disturbance was suddenly detected by Enterprise, while the starship was traveling to Azati Prime. The disturbance was directly on the vessel's course to that destination. () The phenomenon was similar to the disturbance previously discovered by Enterprise. () Since the ship would take two weeks to go around the newly created trans-dimensional disturbance and the phenomenon was still undergoing early changes, the crew decided to take measures to allow the craft to instead traverse the disturbance at impulse speed. Doctor Phlox managed to counteract the effects of the disturbance by placing each of the crewmembers in a coma during the journey, which took four days. ()

In the 26th century of an alternate timeline, a trans-dimensional disturbance was used as the battleground for the Battle of Procyon V. That disturbance, during the conflict, stretched fifty thousand light years in all directions and was continuing to grow. Temporal Agent  brought Enterprise NX-01 Captain Jonathan Archer to witness the trans-dimensional disturbance and the battle inside it from the observation deck of the , which was one of the ships inside the disturbance. Unlike in other cases, though, conditions aboard the Enterprise-J did not include the auburn atmosphere and light-smears associated with most other trans-dimensional disturbances. Nonetheless, Archer – while aboard the craft – mentioned he'd seen a similar phenomenon before, a fact Daniels was well aware of. He didn't know, however, that Archer was already aware the trans-dimensional disturbances were being used to reconfigure space as a prelude to invasion. ()

Enterprise NX-01's first encounter with a trans-dimensional disturbance was mentioned by Captain Archer to the Xindi Council, when he tried to persuade the Council members that the Sphere-Builders were duplicitously working against them all. ()

The Sphere-Builders used Sphere 41 to generate another trans-dimensional disturbance, as the Sphere-Builders determined that the Enterprise crew wanted to destroy the sphere network by sabotaging that particular sphere. While Enterprise was heading towards the sphere, the ship detected the new disturbance, which was increasing in size. At first, Ensign Travis Mayweather couldn't determine precisely what the disturbance was and reported to T'Pol, "Could be spatial anomalies... but they're clustered much tighter than we've ever seen them." The trans-dimensional disturbance was identified by Dr. Phlox, who warned T'Pol that entering the disturbance would prove fatal for the entire crew in a matter of minutes. Synthesizing a neuroleptic compound would keep the crewmembers conscious for about twelve minutes, allowing them to carry out their mission of disabling the sphere network, though there wasn't anything Phlox could do to prevent epidermal decay.

By the time Enterprise arrived at the new trans-dimensional disturbance, it had grown to become a thousand kilometers deeper than when the ship had first detected it. Phlox had enhanced the neuroleptic compound as much as he possibly could, enabling the ship's crew to remain inside the disturbance for up to fifteen minutes. Shortly after the doctor announced he had enhanced the compound as much as he could, the disturbance was penetrated by Enterprise. The phenomenon – despite the tight deadline, the crew suffering epidermal decay that Phlox had been expecting, plus the fact that several Sphere-Builders appeared aboard the ship itself and caused havoc there – facilitated Enterprises journey to Sphere 41. Once the ship eliminated that sphere and thus destroyed the network, the disturbance disappeared, implying that the transformed space inside it was imploding, and the Delphic Expanse became normal space again. ()

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Additional reference

Background information 
In the script of "Harbinger", the trans-dimensional disturbance was mostly termed a "spatial disturbance". In the final draft script of "Doctor's Orders", this wording was used interchangeably with "trans-dimensional disturbance", the latter of which was additionally used in the script of "Azati Prime", though the disturbance in that installment is not given a full name, on screen. As regards this type of anomaly, the term "spatial disturbance" was only ever used in script sources. The term "light-smears" comes from the script of "Harbinger", too.

In the teleplay of "Harbinger", the disturbance was at first described as "colossal" and the same scene description went on to comment, "It's reddish orange, suffused with whipping bands of light and pocked with what appear to be smaller, fiercer disturbances that spring up and burst like bubbles in magma. Weird, blister-like formations continually form across the surface of the disturbance."

In the final draft script of "Doctor's Orders", the trans-dimensional disturbance in that outing was initially described thus; "The background of stars seems oddly distorted – the stars glow with a reddish-hue (similar to the spatial 'disturbance' in 'Harbinger', though not as extreme)."

The trans-dimensional disturbance from "Harbinger" was again referenced in the final draft script of , as it characterized the Sphere-Builders' trans-dimensional realm as "a surreal cousin" of that earlier phenomenon.

In the final draft script of , the space inside a trans-dimensional disturbance was described as "strange, bubbling 'terraformed space,' as seen in 'Harbinger'." The particular trans-dimensional disturbance seen in "Zero Hour" was described as "colossal" and "reddish-orange, with weird, blister-like formations" as well as being a "strange realm".

Astronomical phenomena