Essay About Frost Line And Curious Features Of Mercury

A Comparison of the Planets in the Sol System
Essay title: A Comparison of the Planets in the Sol System
A Comparison of the Planets in the Sol System
Shaun J.
Sci350
December 19, 2004
Introduction
Beginning Mercury, this paper will compare the nine planets and major moons
of our solar system and describe their individual characteristics. At the
end of this discussion, the habitability factor of these different worlds
will be discussed as compared to that of the Earths.
A Brief History of the Sol System
By radiocarbon dating meteorites, we know that roughly 4.6 billion years
ago our solar system began. This happens when a cloud of gas and dust were
disturbed and squeezed by perturbations of the surrounding space, possibly
caused by an exploding supernova. As the cloud began to contract and spin
around a common center of gravity, it also began to heat. After about 10
million years of condensing and heating, our solar system began to take
shape. Towards the center of the cloud, it was hot with cooler areas at the
edge. It is possible that this heating and cooling was even within the
cloud. A line called the frost line began to grow. Inside the frost line,
planetesimals made of rocks and metals began meshing and colliding, becoming
the terrestrial planets. Outside of the frost line, nebulae were accreting
around ices and would become the Jovian planets. The cloud further
contracted towards its center and eventually became hot enough to begin
nuclear fusion. This is the birth of our star, the Sun, and of our solar
system. Stellar winds from the ignition blew excess materials into the
fringes of our newly formed solar system as well as the interstellar medium.
The Nine Planets
During the accretion phase of the birth of our solar system, hundreds to
thousands of planetesimals congregated and coalesced. However, eight true
planets have survived to this day with the ninth possibly being the largest
of the Kuiper Belt objects. These planets are broken into two sections,
inner solar system and outer.
The Inner Solar System Planets and Moons
Mercury (The Messenger of the [Greek] gods)
Mercury is the smallest of the inner solar system planets is also the
closest to the sun. At .39 AU (1 AU = 93,000,000 miles), it orbits the sun
every 87.9 days, faster than any other planet in the solar system. Mercury
is composed of rocks and metal (iron mostly) and has a day temperature of
797o F and a nighttime temperature of -240o F. There is no atmosphere, no
volcanism, no signs of life and a heavily cratered surface. Mercury is about
a 5th the size of Earth. Some curious features of Mercury are the cracks
around its surface. Some of these cracks have created cliffs that are
thought to be the product of planetary shrinkage, which may have happened
early in Mercurys history when the core cooled and rather rapidly. Mercury
has no moon.
Venus (The goddess of Love)
Venus is the second largest planet within the inner solar system