Answer to Question 1The conditions necessary to maintain a large, permanent liquid ocean include the following:
(1) a planet that moves in a nearly circular orbit around a stable star; (2) the distance of the
planet from the star must be such to provide a temperate environment in which water is
liquid; (3) the planets sun must not be a double or multiple star that provides orbital years
with irregular periods of intense heat and cold; (4) materials that accreted to form the planet
must have included water and substance capable of forming a solid crust; and (5) the planet
must be large enough that its gravity will keep the atmosphere and ocean from drifting off
into space.
Answer to Question 2During Earths formation, gases trapped within the planet began to vent to the surface
through volcanic outgassing. As the hot vapors rose, they condensed into clouds in the cool
upper atmosphere. In addition, icy comets or asteroids colliding with Earth may have
contributed a portion of the accumulating water on Earth. As Earth cooled, outgassed water
began to form droplets and hot rains fell to Earth for millions of years forming a deep ocean.
From space earth shows itself as a planet covered mostly by water.
Uranus's aurorae against its equatorial rings, imaged by the Hubble telescope. Unlike the auror
Mixting Hot Cold water
Water-based Diseases
The Distribution of Water on Earth
Planet Z-34 has a mass equal to 1/3 that of Earth, a radius equal to 1/3 that of Earth, and an ...