Learn about the planet Mars, such as its surface mars and atmosphere.
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The Beginning of Mars Four and a half billion years ago, the planets were formed from the gas and dust of the solar nebula. In the formation of a planet, heat is released and becomes embedded in the growing mass. Because the heat can’t escape as rapidly as the mass is growing, a point is eventually reached where the interior melts. On Mars, the heavier material sank towards the center while the lighter material rose to form an icy crust on much of the surface. A lighter stage may have occurred when molten rock intruded into the crust and melted the ice causing slurry of water and rock and dust to flow across the surface. Some observers believed that such a process may have been the cause of the major channels which we see on the surface of Mars today. Others believed that in the planet’s first billion years, the atmosphere may have been warm and dense enough for rain to fall and rivers to flow. Gradually, the original big, wet and warm blanket of the atmosphere evolved into the thin, dry, carbon dioxide filled atmosphere we find that today. Because of Mars’s low atmospheric pressure and low temperatures, water can’t exist in liquid form. It must either freeze or evaporate. But while there are no oceans or rivers on Mars, there’s more water in total than anyone had expected. The residual polar cap in the north which remains after the hottest part of the Northern summer is a mixture of ice and dust. And the measurements of the seasonal behavior of water vapor over the planet suggest that there’s a vast reservoir of ice beneath the surface. In fact, the residual polar cap could be compared to the tip of an iceberg protruding from a sea of rocks. At lower latitudes, the water vapor condenses to form clouds that hang high in the atmosphere or squirl around the tops of Martian volcanoes. And for the south and the canyons and valleys there is frequently an ice haze seen to form and evaporate in the early hours of the morning as the sun warms the atmosphere. On earth, the oceans, heat and moisture and the air currents over land masses interact to produce complex weather patterns. On Mars because of the absence of large bodies of water or massive cloud cover, the weather doesn’t vary much from day to day. But in the early summer, the heating of dust particles in the air generates violent dust storms in the lower regions of the planet. Driven by winds that reach up to 150 miles an hour, they can blanket the entire planet in a few days.

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