Ufsandakh

Ufsandakh

Mean Distance from sun:	65,248,000 km .43616 AU .61990 GAU
Perhelion:	60,860,000 km
Aphelion:	69,636,000 km
Orbital Period:	126 d, 17 h, 29 m
Eccentricity:	.067253
Sidereal day:	126 d, 17 h, 29 m
Diameter:	18,895 km
Surface area:	1,121,600,000 km²
Axial tilt:	0º
Mass:	2.043×1025 kg (3.421 Earth-masses/3.864 Galhaf-masses)
Gravity:	15.278 m/s² 1.5580 g 1.6196 Galhafan gravity
Number of moons:	0

Ufsandakh is the third planet orbiting Chihazh, and one of two known life-bearing planets in the Chihazh system. At one time, it as thought by some to be the homeworld of humanity, but that is now known not to be the case, as Ufsandakhan life uses different biochemistry than human-type life and native Galhafan life.

Etymology

The name Ufsandakh is derived from Classical Sanle Pshán tkab "bright star", due to its being a very bright planet in Galhaf's night sky. The Sanle name was borrowed as waFsantakav.

Physical structure

Ufsandakh is significantly larger than Galhaf or Earth, being the largest terrestrial planet in the Chihazh system.

Observational history

Ufsandakh is one of the brighter planets in the night sky, due to its high albedo. It was among the earliest planets observed by telescope. As soon as telescopes of sufficiently high resolution were invented, the existence of oceans and clouds on Ufsandakh were revealed, leading to excited speculation about life on other worlds. It has long attracted the imagination of sci-fi authors, and was once thought by many to be the homeworld of humanity. The fact that it's tidal-locked was a major obstacle, as humans did display a circadian rhythm very similar to Galhaf's day, but the supporters of the Ufsandakhan Origin Theory argued that humans had adapted to Galhaf's circadian rhythm. One variant that was once popular proposed that some massive geological catastrophe occurred on Ufsandakh that caused once-great continents to sink beneath the ocean, or some kind of "slip" in its rotation causing a continental mass to shift to the nightside, resulting in an exodus of refugees to Galhaf. This theory has been thoroughly discredited, however.

Geology and climate

Ufsandakh is tide-locked to Chihazh. As a result, the planet can be divided into three broad zones, the dayside, the nightside, and a broad zone between the two in which, due to libration, a year-long (127-day) day/night cycle occurs.

Ufsandakh has an active system of plate tectonics, more active than Galhaf's. It has several continents, which are almost entirely covered by ocean. Several highlands and mountain ranges do emerge above the ocean. Overall, the planet is warmer than Galhaf, though not to the extent one might expect from it being nearly twice as close to Chihazh, as the greenhouse effect is weaker. The high temperatures cause significant evaporation, resulting in large areas covered by clouds at any given time, and heavy rainfall. Between the heavy rainfall and the stronger gravity, erosion tends to be very rapid on exposed land. Active plate tectonics continues to create new areas of dry land from volcanism and orogeny.

Biology

Ufsandakh is home to a third biota. Biota is a term used to describe all organisms derived from a single abiogenesis event, originally created to distinguish the native Galhafan life from the Human-type life. Ufsandakhan life uses different amino acids from Galhafan and human-type life, and is thus even more distinct from the other two.

Due to the rapid erosion on Ufsandakh, dry land tends to be relatively short-lived, which has hindered the evolution of land life. Most land life is actually amphibious. With the exception of flying animals, fullscale terrestrial adaptations are an evolutionary dead-end, and few islands last long enough for a full sea-to-land transition to occur. The massive volume of ocean allows for a wide diversity of life. There are also large areas of shallow seas, creating isolated habitats of shallow-sea life, promoting significant biodiversity. In addition, the geographic variation in sunlight, from the region directly underneath the Sun, to regions where the solar angle is lower, and thence to the libration zone and varying periods of daylight, create a ripe environment for plant specialization. There is evidence of the possible existence of at least one sapient aquatic species. The night side has sparse life. The perpetual darkness prevents any photosynthesis from occurring. There is some life, however, sustained by organic material brought in by wind or sea current, and by chemosynthesis around geothermal vents and the like. Most life is on the dayside or the libration zone.

Evolution

Ufsandakh would not have yet been tide-locked when life first appeared. It is estimated to have taken somewhere between 1 and 2 billion years for Ufsandakh to become tide-locked. The first life would thus have experienced regular day/night cycles, which would've become gradually longer. It is, at this time, unclear how exactly life coped with the transition to a tidally-locked planet.