Oortean Type Asteroid
Asteroidal Class. Cometary bodies which can be found throughout the solar system. They may also be constituent members of outer planet ring systems, or they may be outer planet moons.

Throughout recorded history, and quite likely a good deal before it, comets have long been apparitions to frighten humans, to inspire them, and to serve as heavenly messengers of a sort. No other celestial body has caused such wide spread panic in a human population, or has so effectively changed the course of history. In many ancient Earth cultures comets were seen as harbingers of doom. Others saw them as the announcers of kings and emperors. It was not until comparatively late in human history that anyone began to truly wonder about the true physicality of comets, and it was not until even later that anyone came remotely close to the truth.

Oortean class
Image from John M Dollan

Although classically known as comets, these small worlds are classified as Oortean bodies. The name is derived from the Oort Cloud, the reservoir that could be viewed as the last remnants of the planetary accretion disk, from which all other bodies in the solar system formed. All comets originate from this region, although their final orbits are often shaped by planetary encounters as they pass through the solar system.

The gravity of passing stars can actually have a marked effect on comets in the Oort Cloud, and even a seemingly small nudge is enough to send them on a course towards their parent star. But their initial orbits are long and drawn out, and simply to reach the inner regions of the solar system can take hundreds of thousands of years. But once they do begin to pass through the more populated regions, planetary gravity can effect their orbits just as easily. Some comets will eventually find themselves in fairly stable long term orbits of hundreds of years, while others can be trapped in an orbit that is only a few years in length. Many other comets pass through the solar system only once, moving on a sun-grazing path that will eventually shoot them out of the solar system all together. And still others will even impact their sun.

Of course, Oorteans are also a threat to inhabited planets. Unlike asteroids, comets can appear unexpectedly, and often undetected until it is too late. Evidence of impacts on Gaian worlds by comets are common, including Earth. Although asteroids, usually of a bit sterner composition, can do more damage, comets are still very dangerous. One famous example is the Tunguska Event of 1903 AD, on Earth, in which a fragment of a short period comet impacted the northern Siberia region. Although the area was unpopulated, the blast was witnessed by thousands hundreds of miles away, and the resulting dust cloud from the air burst reflected sunlight down around the planet well after the midnight hours.
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Development Notes
Text by John M. Dollan Planet Classification List
Initially published on 24 September 2001.