MERCURIAN WORLDS

Summary of properties:

Though most Mercurian worlds in their present state have little of interest, sometimes their pasts can be quite interesting, and these ‘dead’ worlds of a solar system have their origins at nearly every stage imaginable. These worlds are often small, have little or no atmosphere, and their volatiles long since escaped to space, most have ceased any further geological development.

Detailed description:

Mercurian worlds have a variety of origins, most are formed from the nightmarish worlds of the solar system’s creation, being too small to retain their atmosphere, or are stripped of it by fierce solar events these initially chaotic worlds radiate their heat to space, their surface hardening as a result. Though they initially have tectonic activity they are generally too small and cool to rapidly to retain this activity for long. Sun close Mercurians often tidally lock to their suns allowing one face to be perpetually exposed to the suns radiance (in some cases maintaining a molten surface), while the other side freezes out as its heat slowly radiates away.

Though most Mercurians come directly from the smaller Hadean worlds of the solar systems early formation, many others have different origins. Earth’s moon is a good example of a Mercurian, though made from the same sort of material that went on to make Earth, it had too little mass to follow the same path, and its molten surface slowly cooled, and became battered by impacts. Most Mercurians share the same characteristic cratered surfaces, as once they have cooled they have no way of changing their surface and so over time accumulate the scars of repeated impacts. This type of Mercurian is called ‘cratered’ but there exists another type which often have much more interesting pasts, these are so called ‘featured’ Mercurians.

Featured Mercurians are noted for their relatively smooth non-cratered surfaces, suggesting that until the bombarding of the early system dies down they were existing as another type of planet. The most common source for this type of Mercurian is the cooling of persistent or perpetual Hadean worlds, whose surfaces are regularly resurfaced by volcanism. Sometimes Mercurian worlds are generated by more interesting means from planets which initially were following the paths of atmosphere bearing worlds, as a result these worlds are generally large enough to display a range of geological features which can no be formed on the smaller worlds, such as mountain ranges not related to impacts, and also oceanic basins and other tectonic features. Generally these worlds are generated from solar cataclysms where either the central sun or nearby sun erupts with great violence ripping away the atmospheres of these large worlds. With no atmosphere and too mature to fully regenerate the original volatiles from outgassing these worlds become Mercurian, though they often retain the interesting geological features that reveals their true pasts.

Sometimes worlds can become Mercurian without the need for stellar cataclysms, already hot planets can become even hotter from runaway greenhouse effect and subsequently lose some of their atmosphere, the rest can be eroded away by the solar wind, eventually rendering the surface of the planet a bare to the vacuum of space. A similar chain of events can lead to the creation of Arean like worlds though here the heat is less intense and rather baking the rock back into a rather uninteresting state, volatiles and a lot of geology are preserved by the cold, also those worlds are able to redeem some of their original hospitability, where as most Mercurian surfaces have been scoured clean of most of their ices and volatiles.

The final source of Mercurian objects are formed after the end of the solar system, the expanding sun strips away the terrestrial planets atmospheres, consuming most as it expands and driving some back into their Hadean state at which they started, the sun then dies down again, this time for good, and the hot scorched worlds turn into Mercurian bodies. Those worlds whose surfaces have been melted by the dying sun slowly solidify in the dark, and form Mercurian bodies where their surfaces are mostly bereft of craters but are instead only marked by the actions of volcanism.