Terrestial+Planets

The terrestrial planets are Mercury, Venus, Earth, the moon, and Mars. The composed of rock and heavy metals they are inner planets because they are closer to the sun. Mostly made of iron cores surrounded with mantle of silicate rock. They are much smaller than gas giants. They have few or no moons They don’t have planetary rings made of gas.

Venus and Earth are very similar in size. Mars is half their size, and Mercury is even smaller. The Moon is one quarter the diameter of Earth, or one half the diameter of Mars.

On average, Mercury is only about a third as far from the Sun as Earth is. That makes the Sun 11 times hotter at Mercury than at Earth. Mars's distance from the Sun is 50% greater than Earth's, which makes the Sun only half as strong there. [] Earth and Venus have similar gravity. So do Mercury and Mars, even though Mercury is much smaller -- it is made of denser stuff.

Mercury records the greatest extremes of temperature of any place in the solar system because of its lack of atmosphere, closeness to the Sun, and long solar day. The Moon also has fairly extreme temperatures Venus has the hottest surface of any terrestiral planet due to its insulating atmosphere and runaway greenhouse effect. Its atmosphere is made up of carbon dioxide and sulfuric acid. The surface temperature is 900º Venus' atmospheric pressure is 90 times that of the Earth

Earth is the densest of them because of its high percentage of iron

The terrestrial planets are composed primarily of rock and metal and have relatively high densities, slow rotation, solid surfaces, no rings and few satellites [|http://nineplanets.org/overview.html#ter_p]

what if the terestial planets were situated beyond the asteroid belt instead of on the asteroid belt.

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Developed from small grains of dust that collided and formed together. []


 * Terrestrial Planet Finder** is a mission concept currently under study by NASA for a potential future mission suite. TPF would study all aspects of exoplanets: from their formation and development in disks of dust and gas around newly forming stars to their suitability as abodes for life.

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