When the scientists at Heterodyne Consolidated Industries performed their initial testing of the trans-temporal displacement generator, they sent inorganic objects - special sensor pods equipped with an extensive array of measuring devices - to and from the past. Occasionally, chronitons would build up to unexpectedly high levels , causing the sensor pods to be bombarded by chroniton particles.
This chroniton bombardment did not seem to have any deleterious effect on the sensor pods. Nevertheless, the engineers added a feedback buffer to the displacement generator, intended to syphon off chronitons and prevent excessive particle buildup within the displacement matrix. Problem solved!
Eventually, the Heterodyne Consolidated team began to send living test subjects to and from the past. These animals (ranging from actual guinea pigs to chimpanzees) did not suffer any harm during temporal displacement. After extensive testing with these animals, the scientists decided that it was safe to move forward with human trials.
The human trials proceeded without incident for several weeks. Then, one day, the scientists sent one of their human volunteers - a member of the research team named Tanya Nielsen - several days into the past. They retrieved Tanya without any problems. However, when she appeared on the transmat pad, a second figure materialized on one of the other transmat pads at the same time.
The second figure appeared to be, at first glance, some sort of mannequin or statue composed of a shimmering, translucent material. They recognized the facial features of this 'statue' as those of another member of the research team, Marta Delgado... who was, inexplicably, missing. No one could recall having seen her for several days.
The mystery deepened when the team questioned Tanya Nielsen. She insisted that Marta had been a participant in the same test sequence that had sent her into the past. Tanya explained that the parameters of the experiment involved sending her three days into the past to 'tag' another member of the research team with a retrieval transponder; this second subject was to be pulled into the present, scanned, then returned to the past.
According to Tanya, Marta had volunteered to be the second subject for this experiment. Furthermore, Marta had talked to the team about her participation in the experiment at a pre-test briefing that very morning; Marta remembered having been temporally displaced then returned to her own personal timeline without incident. She even joked about how weird it was to see her future self standing with the other members of the team during her brief visit to the 'future.'
None of the other members of the team had any memory of Marta being at the pre-test briefing that morning.
While there had been discussion of carrying out an experiment along the lines of the one that Tanya had described, the scientists did not remember that particular test having been approved, let alone implemented. These discrepancies between their recollection of events and Tanya's had alarming implications. It became increasingly clear that some sort of temporal paradox was involved.
After examining the trans-temporal displacement generator, the engineers found an error in the event log. The feedback buffer on transmat pad number two had experienced a catastrophic failure, causing chroniton particles to flood the displacement matrix. The log also offered an explanation for why transmat pad number two had activated in the first place; it had received a remote retrieval signal from one of the team's transponder tags.
Presumably, that was the transponder Tanya claimed to have used to tag Marta in the past, as part of the experiment.
The scientists subjected the 'statue' of Marta to a battery of tests. They quickly determined that the statue was, in fact, Marta Delgado. They also discovered that it was composed of a previously unknown form of exotic matter, which they dubbed 'chronitite.' The most notable trait of chronitite was that it existed in a state of temporal discontinuity; it was either not subject to the passage of time, or time moved very, very slowly for it. So slowly that their instruments were not able to measure it.
As a consequence of this temporal discontinuity, chronitite proved to be virtually indestructible and offered no resistance to electrons passing through it, making it a perfect superconductor. It was also a perfect thermal superconductor; when in contact with two materials of different temperatures, it transferred thermal energy from one to the other until they reached equity.
When the scientists placed one of the statue's feet in a blast furnace and the other in a bucket of water, the water begin to boil away immediately.
While this miraculous material could potentially be tremendously useful for humankind, subsequent testing revealed several drawbacks. First, chronitite could only be created by bombarding living organic matter with chronitons within the displacement matrix after it had been temporally displaced. Bombarding temporally-displaced inorganic matter had no effect.
Second, the process only worked on subjects that had been temporally displaced from the past into the present. When test animals were bombarded with chronitons during initial displacement from the present into the past, they arrived unharmed. Conversion to chronitite only occurred when test animals were subjected to chroniton bombardment while being displaced from the past into the present, or while being returned to the past after they were brought into the present.
Curiously, the scientists were able to fully document the conversion process with some test animals, but in other cases converted animals suddenly appeared in the test chamber without any record of the experiment in which they had been involved. Clearly, some sort of temporal paradox was at work in the latter cases, but the scientists could not determine why paradoxes did not occur in the other cases.
Since the research team could not devise a hypothesis to predict when a paradox would occur and when it would not, it meant that chronitite could not be created without running the risk of timeline disruptions such as that which had been observed in the case of Marta Delgado. In her case, the disruption only affected three days. Theoretically, the potential severity of the timeline disruption would increase exponentially the farther back in time from which the subject was displaced.
All of the chronitite research came to light during the authorities' investigation into the disappearance of Marta Delgado, whose family had reported her missing after Heterodyne Consolidated gave them contradictory answers regarding her whereabouts. Needless to say, the authorities were alarmed by the implications.
Upon receiving a full report on the dangers involved with chronitite conversion, the United Earth Parliament made the creation of chronitite illegal. It also established the Temporal Regulatory Agency to enforce this proscription and monitor all practical applications of time travel moving forward.