The Encyclopædia Planetæ

[this will be the Encyclopædia Planetæ logo]

Introduction

THE RISE OF MODERN astronomical study occurred, for the most part, in the Twentieth Century when the technological means of discovery became widespread and grew more refined, seemingly year by year.  It was in the 1990's that these methods became sophisticated enough to give Humanity its first glimpses of worlds beyond Sol.

Initially, little about these worlds could be determined beyond their orbital parameters and masses.  Many times even these were not known with great accuracy.  Regardless, it was this late period of the century, and much of the early Twenty-First Century, that saw an explosion of world discoveries.  Detection methods, largely based on astrometric or radial velocity measurements, with some transiting methods mixed in, provided a basis for these astronomers to make some assumptions about the population of worlds within what would become the Local Neighborhood.  It was recognized, of course, that the types of worlds discovered were inevitably biased towards the detection methods, namely in that large-massed worlds in close orbits were those that filled the early discovery catalogues.  While discoveries were made which broke this mold from time to time, little would change until 2015 CE, when the ExoMAP Array was placed in Solar orbit.

ExoMAP was designed to be able to directly image planets as they orbited their host stars, out to a distance of nearly 50 light years.  The images themselves, a result of the newest technologies in adaptive optics, showed little more than dull spots next to greatly dimmed stars, but the gathering of this planetary light allowed for rudimentary spectroscopic investigations.  Because of this, scientists gathered the first direct indications of the composition of some of these worlds.  It was a quantum leap forward in extrasolar investigations, and provided the first hints of biological-friendly environments beyond the Solar System.  Free oxygen had been detected on some worlds, something that was almost exclusively the result of biological activity.  And while this finding was bolstered by the fact that most of the oxygen-bearing worlds came from apparently terrestrial worlds in their stellar habitable zones, it could not be definitively stated that life was indeed responsible.  Other mechanisms were conceived of which could account for the oxygen, and until those mechanisms could be disproved, life could not be confirmed.

This would be achieved in 2042 CE when, for the first time ever, a new imaging technique was utilized to view a world and confirm the presence of life, and not only revitalize the entire field of extrasolar world and SETI-type studies, but to turn Man's serious attention to the prospects of colonizing worlds light years away.  The world of Ghellhonus, orbiting Alpha Centauri A, had long been suspected and hoped to be life-bearing.  With this first image, revealing details down to the size of small continents, it was easy for even the layman to tell that the world was a twin of Earth.  But more so, spectroscopic readings could be taking in extreme detail, and in this case they not only confirmed the presence of oxygen and nitrogen, but they also detected carbon dioxide, chlorophyll, ozone, and small amounts of methane.  Not only had the field of world detection moved far beyond the wildest hopes of those first planetary astronomers, and with a viewing range of nearly 40 light years, with the detail of the measurements decreasing incrementally beyond that point, but Mankind had been shown that, at least as far as the plain presence of life went, he was no longer alone.

IT WAS NOT LONG after this direct imaging that the catalogue of worlds, already quite expansive, became quite complicated.  It was generally accepted that nearly all stars within 50 light years had been sufficiently mapped to a degree of accuracy equal to what the world knew of the Sol System by the year 1970 CE.  Most stellar systems contained eight or ten worlds, while some few contained much larger numbers.  It was soon clear that a direct listing was no longer practical, and so the Encyclopædia Planetæ was published.  Updated every year, the Encyclopædia has since become the premiere source of information for the public, and has been critically acclaimed with nearly every new publication, despite the use of the world-form "planet" in the title (the usage of which was largely abandoned by the astronomical community in the 2010's after the previous decade's semantic contention regarding the word and what bodies it could be applied to).

As exploration, colonization, and movement through the ArcWays continues, as well as the gathering of information second-hand through reliable sources such as the Tsubar'ey Corpus, the Encyclopædia continues to expand.  Organized by distance from Sol, it thus by default roughly follows the path and timeline of Human colonization.  The regions which divide up the Local Neighborhood are a naming product of the League of Worlds, of course, although the Neighborhood itself was a term put in use since the earliest days of direct world detection.  Various worlds in these regions were colonized at different times, but even in this modern age systems within the closer regions, such as the Mid Volumes, are still being explored for the first time, just as are worlds in the Frontier and Beyond.

Today the Encyclopædia is an expansive volume that, when used in conjunction with the Planetary Classification List, affords the user a fine understanding and knowledge base of the League of Worlds, and the many worlds that comprise it.  With the ArcWays, most inhabited worlds are literally a step away, and it is advantageous to know what sort of world one might walk into.