Download Inner Planets The inner four planets are called terrestrial planets

Inner Planets
The inner four planets are called terrestrial planets.
That means that they are like the earth in some
ways. The terrestrial planets Mercury, Venus,
Earth, Mars, and the earth's moon have similar
compositions and densities. These planets are close
to the sun, rocky, and dense. They are fairly small.
They have few moons and no rings. Their
environments are oxidized; that is, oxygen
dominates the chemistry. Meteors, tectonic activity,
and erosion have modified the surfaces of the
terrestrial planets.
The atmospheres of the terrestrial planets have
changed as a result of sunlight (which produces
chemical reactions, such as those that break apart
water molecules), escape of light gases, volcanic
activity, and in the case of our planet, biological
activity.
The main stages of evolution of the terrestrial
planets are:
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formation
impacts (during the period of early
bombardment)
flooding of basins with lava
lessening of impacts, and, in some cases, the
formation of an atmosphere
plate tectonics
lower activity
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cooling, inactivity
Mercury is the planet closest to the Sun, but
surprisingly not the hottest. Because it has almost
no atmosphere, there is no greenhouse effect to trap
the heat, so temperatures vary from extreme hot to
extreme cold. In fact it has the widest day/ night
temperature change in the solar system. Its surface
of craters resembles the Moon because it has been
bombarded by comets etc. The planet was named
for the Roman god Mercury, a winged messenger,
and it travels around the Sun faster than any other
planet. Mercury is difficult to see from Earth.
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Size: 0.382 the diameter of Earth;
Diameter: 3,032.4 miles (4,880 km)
Atmosphere: A thin mixture of helium (95%)
and hydrogen
Temperature: The sunlit side can reach up to
950°F (510°C) and the dark side can drop as
low as -346°F (-210° C),avg day temp =
662°F,avg night temp= -274°F
Rotation (1 Day) = 59 Earth days
Revolution (1 Year) = 88 Earth days
Your weight: If you weigh 100 pounds on
Earth, you would weigh 38 pounds on
Mercury.
Distance from Earth: 57 million miles, at the
closest point in its orbit
Mean Distance from Sun: 36 million miles
(57.9 million km)
Satellites: 0
Rings: 0
Venus is the brightest planet in the sky because it
is very reflective - it is covered in clouds. It has a
tremendous greenhouse effect that does not allow
the heat to escape leaving the temperature to hover
around 880°F which makes it the hottest planet in
the solar system. Venus is often called Earth's twin
because the two planets are close in size, but that's
about the only similarity. Venus' rotation is not
only extremely slow but it is also backward or
retrograde. Venus is named after the Roman
goddess of love and beauty and appears as a bright,
white disk from Earth.
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Size: About 650 miles smaller in diameter than
Earth
Diameter: 7,519 miles (12,100 km)
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Surface: A rocky, dusty, waterless expanse of
mountains, canyons, and plains, with a 200mile river of hardened lava
Atmosphere: Carbon dioxide (95%), nitrogen,
sulfuric acid, and traces of other elements
Rotation (1 day) = 243 Earth days (retrograde
rotation or "backward")
Revolution (1 year) = 225 Earth days
Your weight: If you weigh 100 pounds on
Earth, you would weigh 88 pounds on Venus.
Satellites: 0
Rings: 0
courtesy of NASA
Earth is the third planet from the sun and is 4.6
billion years old as determined by radioactive
dating. It is 5.5 times denser than water on average.
Its inner core is made up of solid iron with a molten
outer core that produces its magnetic field. Earth's
atmosphere is made up of 78% Nitrogen, 21%
Oxygen, and traces of other elements. Our
greenhouse effect regulates the temperature on
Earth and is essential for our survival. Also, Earth
is not perfectly round; it bulges at the equator and
is flatter at the poles.
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Size: Four planets in our solar system are
larger and four are smaller than Earth
Diameter: 7,926.2 miles (12,756 km)
Surface: Earth is made up of water (70%), air,
and solid ground. It appears to be the only
planet with water
Atmosphere: Nitrogen (78%), oxygen (21%),
other gases
Rotation of its axis: 23 hours, 56 minutes, 4
seconds
Rotation around the Sun: 365.2 days
Mean Distance from Sun: 92.9 million miles
(149.6 million km)
Satellites: 1
Rings: 0
Mars is the fourth planet from the Sun, situated
between Earth and Jupiter. The surface of Mars
contains silicon dioxide and iron oxide. The iron
oxide is rust, which gives it a reddish color. Mars
has two moons Phobos and Deimos. Like our
moon, the two moons keep the same side toward
Mars as they revolve around the planet. They are
small and appear to be captured asteroids. Mars has
the largest volcanic mountain in the solar system,
Mt. Olympus, which is 2.5 times the size of Mt.
Everest. The poles of Mars are covered with frozen
water and frozen carbon dioxide producing white
polar ice caps. There can be no liquid water due to
the thin, low pressure atmosphere which allows
water to vaporize.
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Size: About one-half the size of Earth in
diameter
Diameter: 4,194 miles (6,794 km)
Surface: Canyons, dunes, volcanoes, and polar
caps of water ice
Atmosphere: carbon dioxide (95%)
Temperature: as low as -305°F (-187°C)
Rotation of its axis: 24 Earth hours, 37 minutes
Rotation around the Sun: 687 Earth days
(almost 2 Earth years)
Your weight: If you weigh 100 pounds on
Earth, you would weigh 38 pounds on Mars.
Distance from Earth: 35 million miles (56
million km) at the closest point in its orbit
Mean Distance from Sun:141.71 million miles
(227.9 million km)
Satellites: 2
Rings: 0
References
http://www.ronyerby.com/ss/Inner.html
courtesy of NASA