A Case of Conscience

The relatively high CO₂ concentration (partial pressure about 11 times that of the gas in the Earth's atmosphere) leads to a hothouse type of climate, with relatively slight temperature differences from pole to equator. The average summer temperature at the pole is about 30° C., at the equator near 38° C., while the winter temperatures are about 15° colder. The humidity is generally high and there is a lot of haze; gentle, drizzling rain is chronic. There has been little change in the climate of the planet for about 700 million years.

Since there is little vulcanism, the CO₂ content of the air does not rise appreciably from that cause, and the amount consumed in photosynthesis by the lush vegetation is compensated for by the rapid oxidation of dead vegetable matter induced by the high temperature, high humidity, and high oxygen content of the air. In fact, the climate of the planet has been in equilibrium for more than half a billion years. As has the geography of the planet. There are three continents, of which the largest is the southern continent, extending roughly from latitude 15° south to 60° south, and two-thirds of the way around the planet. The two northern continents are squarish in shape, and of sizes similar to each other. They extend from about 10° south to about 70° north, and each one about 80° east and west. One is located north of the eastern end of the southern continent, the other north of the western end. On the other side of the world there is an archipelago of large islands, the size of England and Ireland , running from 20° north to 10° south of the equator. There are thus five seas or oceans: the two polar seas; the equatorial sea separating the southern from the northern continents; the central sea between the two latter, " and connecting the equatorial sea with the north polar sea; and the great sea, stretching from pole to pole, broken only by the archipelago, extending a third of the way around the planet.

The southern continent has one low mountain range (highest peak 2263 meters) paralleling its southern shore, and moderating the never very momentous effect of the south winds. The northwestern continent has two ranges, one paralleling the eastern and one the western sea, so that the polar winds have a free run, and give this continent a more variable climate than that of the southern one. The northeastern continent has a slight range along its southern shore. The islands of the archipelago have few hills, and possess an oceanic type of climate. The trade winds are much like those of Earth, but of lesser velocity, due to the lesser temperature differentials between the different parts of the planet. The equatorial sea is nearly windless.

Except for the few mountain ranges, the terrain of the continents is rather flat, particularly near the coasts, and the lower reaches of all the rivers are of the meandering type, bordered with marshes, and with low plains that are flooded, miles wide, every spring.

There are tides, milder than on Earth, producing an appreciable tidal current in the equatorial sea. As the coastal terrain is generally quite flat, except where the mountain ranges come to the sea, wide tidal flats separate the shore from the open sea. The water is similar to that of earth, but considerably less salty. Life began in the sea, and evolved much as it did on Earth. There is a rich assortment of microscopic sea life, types resembling such forms as seaweed and sponges, and many Crustacea and mollusklike forms. The latter are very highly developed and diversified, particularly the mobile types. Quite familiar fishlike forms have emerged and dominate the seas as they do on Earth.

Present-day Lithian land plant life would be unfamiliar, but not surprising, to a terrestrial observer. There are no plants exactly like those of earth, but most of them have a noticeable similarity to those with which the visitor would be familiar. The most surprising aspect is that the forests are of a remarkably mixed type. Flowering and non-flowering trees, palms and pines, tree ferns, shrubs and grasses all grow together in remarkable amity. Since Lithia never had a glacial period, these mixed forests, rather than the uniform type prevailing on Earth, are the rule. In general the vegetation is lush and the forests can be considered as typical rain-forests. There are several varieties of poisonous plants, including most of the edible-looking tubers. Their roots resemble potatoes and they produce extremely toxic alkaloids, whose structure has not yet been worked out, in large quantities. There are several types of bushes which grow thorns impregnated with glucosides which are extremely irritating to the skins of most vertebrates.