The First Contact Event refers to the discovery and subsequent observations of an extraterrestrial spacecraft, likely a von Neumann probe, in the Kuiper Belt. The event ended with an attempt to rendezvous with the spacecraft, which then changed trajectory and subsequently left the range of all radar satellites. Although the spacecraft is presumed to have left the solar system and no contact has been made since, the event has had significant and lasting effects on society.
Events
The spacecraft was initially registered as an anomalous reading from several gamma ray detectors in the outer solar system, which picked up periodic gamma ray bursts with energy signature not consistent with natural sources. The origin was confirmed to be within the Kuiper Belt when the Submillimeter Array at Titania Armstrong Observatory was directed towards the area and identified an unusual energy signature which did not match any known celestial bodies. The anomaly was subsequently observed by a radar satellite orbiting Neptune, and then several others in the outer solar system. These provided imaging of the object, and the doppler shift helped predict its trajectory, which appeared to change as a result of the active radar.
The imaging revealed a roughly 5m long spherical object, emitting gamma rays which were later determined to be the result of electron-anti-election collisions in an Antimatter Engine. Although the cause of the gamma ray bursts was not known at the time, their existence and the trajectory change, which by this time had been observed by many independent sources, lead to a system-wide crisis as both FreeHab and GZ publicly accused the Peacekeepers of fielding a new first strike weapon system.
Loitering missile swarms were orbited by both GZ and the Peacekeepers, and all three polities moved fleets into high orbit. Freehab had several autonomous survey ships within a few AU and similar trajectories to the object when it was detected, and announced they were moving them to intercept. Over the next several days the lack of further trajectory changes or new objects helped to de-escalate tensions, and all three polities announced they were initiating their respective first contact protocols.
Over the next week the nearest Freehab ship had moved close enough to use infrared thermography from its survey equipment to determine that the object was likely assembling something inside itself. This is now generally accepted to have been the early stages of a second probe, manufactured from material gathered further out in our solar system. Once the survey vessel had closed the distance to 50 million kilometers, the object accelerated into an escape velocity. The fact that it was able to do this without gravitational assistance demonstrated the immense power of the tiny internal engine, and was critical in dispelling doubt about the extra-terrestrial origin of the object. Radar tracking of the object was lost shortly after, and to date there have been no further contact events.
Attribution
It is unlikely that a civilisation at less than a Kardashev 1 level would be able to build a spacecraft that was not only powered by antimatter, but also either carrying enough antimatter for interstellar travel or able to generate more on route. The fact that the probe was gathering resources from the outer solar system and left once approached might indicate that its designers were not expecting life in this solar system. Since any Kardashev 1+ civilisation should be able to remotely observe life in systems within a few tens of light years of itself, one explanation for this is that the probe originated further away where the Earth either couldn't be observed, or couldn't be observed with traces of life at the time the probe was sent. This theory is generally coupled with the assumed motivation for sending the probe being observational.
The leading alternative explanation is that some or all of the destinations of the probe might not have been known in advance when it was sent, this explanation usually assumes that the senders were likely indifferent to us and the probe only adjusted course when it was near enough to be threatened. The assumed motivation in this case is usually that the probe was transiting somewhere, and this is supported by the small size of the probe making it unsuitable for optical and most other known monitoring, and also that its course suggests that it was doing a flyby of the outer solar system rather than a thorough exploration before we intervened. It is even possible that it could have been carrying some radiotrophic life able to withstand the intense gamma radiation in the small craft, perhaps to seed life somewhere. Whatever the senders interest in sending a probe to another system, all we know with any certainty is that based on the exit trajectory the next destination of the probe is likely to be the Sirius binary system.
Technological Impact
Subsequently declassified files show that both the Peacekeepers and GZ immediately launched large scale research and development projects based on data passively gathered from the object. Freehab also launched a smaller scale overt effort, focussed mostly on the engineering of the replicating probe rather than the harder issues of antimatter containment and propulsion that occupied the larger polities.
These programs were likely a large contributor to the successful engineering of the first antimatter engine prototypes in 14 AFC, although public efforts to quantify the impact have been hampered due to a large part of the research still being classified due to the overlap with the military applications of antimatter. Several thousand theoretical and experimental physicists and material scientists worked for these programs, along with an unknown number of synths. Large numbers of terrestrial and orbital datafarms were taken over or built during this period in order to simulate of engine and containment possibilities against the observational data.
Societal Implications
There was widespread panic at the time of discovery until the ship was confirmed to have left, with several terrestrial cities needing to deploy the military to control looting and keep essential services running. Many political parties used the event to advance, and in some cases pass, legislation on matters such as the ethical treatment of animals, religious tolerance, promoting atheism, better direct communication systems between the larger powers, higher defence spending, better sensor networks in the outer solar system, and a renewed focus on off Earth settlement. The majority of people in several large scale surveys at the time reported significantly weaker national political affiliations, and were more favourable to legislation on larger scale issues such as global defence and large scientific projects.
The subsequent years were a period of economic prosperity with a distinct cultural edge, with significant new trends in lifestyle and culture. The period was marked by a general feeling of novelty associated with modernity and a break with tradition. There was a small decrease in those observing the three Abrahamic religions, and a larger increase in people declaring themselves as atheists in census data. There was also a marked decrease in both local conflicts and in violent crimes. Several new inter-faction political entities such as the Outer Trading League were formed during this period, and there was a large increase in migration from Earth to the Lunar and Martian colonies. An informal system of referring to the year of contact as 0 AFC (After First Contact) and prior years as BFC (Before First Contact) developed in popular culture, and over the next decade became so commonplace that it has mostly replaced the Gregorian calender system in daily life system-wide.