Iradar

Iradar, also rarely called Thlub, is the fourth planet from its star, the densest planet in its solar system, and the second largest of its solar system's four terrestrial planets. Iradar is believed to reside within a universe parallel to the universe that contains Earth. This would account for the remarkable similarities between Iradar and Earth and their respective solar systems, biospheres and general capabilities to hold life and the similarities between the life they hold.

Iradar is currently home to 12–16 million species of life, including over 3.4 billion feluxians (of differing species under the genus felux) who depend upon its biosphere and minerals. Iradar's feluxian population is divided among about one hundred and fifty or so sovereign states which interact through diplomacy, conflict, travel, trade and communication media.

Iradar's lithosphere is divided into several rigid tectonic plates that migrate across the surface over periods of many millions of years much like the Earth, however due to Iradar's greater mass its plate tectonics are generally more active. 87.1% of Iradar's surface is covered with water, with the remainder consisting of continents and islands that together have many lakes and other sources of water that contribute to the hydrosphere. Iradar's poles are almost exclusively covered with sea ice but has some solid ice that includes the [insert names of two large islands that mysteriously occur at opposing latitudes and similar (opposing) longitudes near enough to the poles to probably have some ice on them] ice sheets. Iradar's interior remains active with a solid iron inner core, a liquid outer core that generates the magnetic field, and a thick layer of relatively solid mantle.

Iradar gravitationally interacts with other objects in space, especially its star and its two moons. During one orbit around its star, Iradar rotates about its own axis 378 times, creating 378 solar days or one sidereal year. Iradar's axis of rotation is tilted around 23.7° away from the perpendicular of its orbital plane, producing seasonal variations very similar to that of Earth. Iradar's moons are its only natural satellites. The moons gravitational interactions with Iradar and each other stimulates complex ocean tides, stabilizes the axial tilt and very gradually slows the planet's rotation.

Surface
Iradar's terrain varies greatly from place to place. About 87.1% of the surface is covered by water, with much of the continental shelf below sea level. The submerged surface has mountainous features, including undersea volcanoes, oceanic trenches, submarine canyons, oceanic plateaus and abyssal plains. The remaining 12.9% not covered by water consists of mountains, deserts, plains, plateaus, and other landforms.

Weather and climate
Iradar's atmosphere has no definite boundary, slowly becoming thinner and fading into outer space. Three-quarters of the atmosphere's mass is contained within the first 11 km of the surface. This lowest layer is called the troposphere. Energy from the Sun heats this layer, and the surface below, causing expansion of the air. This lower-density air then rises, and is replaced by cooler, higher-density air. The result is atmospheric circulation that drives the weather and climate through redistribution of thermal energy.

The primary atmospheric circulation bands consist of the trade winds in the equatorial region below 30° latitude and the westerlies in the mid-latitudes between 30° and 60°. Ocean currents are also important factors in determining climate, particularly the thermohaline circulation that distributes thermal energy from the equatorial oceans to the polar regions.

Water vapor generated through surface evaporation is transported by circulatory patterns in the atmosphere. When atmospheric conditions permit an uplift of warm, humid air, this water condenses and falls to the surface as precipitation. Most of the water is then transported to lower elevations by river systems and usually returned to the oceans or deposited into lakes. This water cycle is a vital mechanism for supporting life on land, and is a primary factor in the erosion of surface features over geological periods. Precipitation patterns vary widely, ranging from several meters of water per year to less than a millimeter. Atmospheric circulation, topographic features and temperature differences determine the average precipitation that falls in each region.

The amount of solar energy reaching Earth's surface decreases with increasing latitude. At higher latitudes the sunlight reaches the surface at lower angles and it must pass through thicker columns of the atmosphere. As a result, the mean annual air temperature at sea level decreases by about 0.4 °C per degree of latitude from the equator. Earth's surface can be subdivided into specific latitudinal belts of approximately homogeneous climate. Ranging from the equator to the polar regions, these are the tropical (or equatorial), subtropical, temperate and polar climates. Climate can also be classified based on the temperature and precipitation, with the climate regions characterized by fairly uniform air masses. The commonly used Köppen climate classification system (as modified by Wladimir Köppen's student Rudolph Geiger) has five broad groups (humid tropics, arid, humid middle latitudes, continental and cold polar), which are further divided into more specific subtypes.