EARTH & SPACE SCIENCE
Chapter 27 Planets of the Solar
System
27.3 The Inner Planets
27.3 The Inner Planets Objectives
• Identify the basic characteristics of the
inner planets.
• Compare the characteristics of the inner
planets.
• Summarize the features that allow Earth
to sustain life.
Introduction
• The inner planets – those closest to the sun –
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are Mercury, Venus, Earth, and Mars.
The inner planets are also called terrestrial
planets because they are made mostly of solid
rock and have metallic cores.
The number of moons of the terrestrial planets
can vary from zero to two.
Impact craters on the terrestrial planets are
evidence of collisions with other objects in
space.
http://askville.amazon.com/largestdensest-rocky-planets-solarsystem/AnswerViewer.do?requestId
=8907806
http://www.wallpaper-zone.de/wallpapersqueen/wallpaper-6,486,010.html
Mercury
• Mercury is the closest planet to the sun and
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orbits the sun every 88 days.
Mercury rotates once on its axis every 59 days.
The surface is characterized with many craters
and a line of cliffs hundreds of kilometers long.
The cliffs may be the result of the molten core
cooling and shrinking causing wrinkles in the
crust.
Lack of dense atmosphere and the planets slow
rotation contribute to the extreme temperature
change (427°C – day; -173°C – night).
http://wiki.answers.com/Q/
Do_you_have_any_pictures_
of_the_planet_mercury
http://www.sarracenia.com/faq/faq2260.html
Venus
• Venus is the second
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•
planet from the sun
and has an orbital
period of 225 days.
Venus completes one
full rotation every 243
days.
Venus and Earth are
almost the same size,
mass, and density.
http://planetfacts.org/planet-venus-facts/
Venus
• The atmospheric pressure
on Venus is about 90
times that of Earth.
• The high concentration of
CO2 (96%) and its
proximity to the Sun have
resulted in runaway
greenhouse effect.
• Average surface
temperature for Venus
reaches 464°C.
http://www.herebeanswers.com/2011
/07/why-is-there-runawaygreenhouse-effect.html
Venus
• The sulfur dioxide droplets in
the upper atmosphere of
Venus reflect much sunlight.
• Venus appears to be the
brightest object in the sky
except for the sun and moon.
• Because Venus appears near
the sun, it is visible from Earth
only in the early morning or
evening – “morning star” or
the “evening star”.
http://fineartamerica.com/featured/evenin
g-star-a3551.html
Venus
• In the 1970s, the Soviet Union
sent six probes to explore the
surface of Venus.
• The probes transmitted surface
images of a rocky landscape, a
smooth plain, and some rocks.
• The surface of Venus is mostly
basalt and granite.
• In the 1990s, Magellan (United
States) satellite collected
atmospheric data and bounced
radio waves off Venus to
produce radar images of
Venus’s surface.
http://spacechronology.com/1990s.html
http://exoplanet.as.arizona.edu
/~lclose/teaching/a202/lect16.h
tml
Venus
• Scientists discovered landforms such as mountains,
volcanoes, lava plains, and sand dunes.
• Volcanoes and lava plains are the most common features
on Venus.
• Maat Mons is Venus’s highest volcano, at an elevation of
3 km.
• The surface of Venus is also somewhat cratered.
• All of the caters are of the same age and are surprisingly
young.
• Unlike Earth’s surface which is constantly changing
because of the motion of tectonic plates, Venus’s surface
undergoes periodic resurfacing as a result of massive
volcanic activity.
http://tvlistings.zap2it.com/tv/3r
d-rock-from-the-sun/photogallerydetail/EP00163817/293950
http://visibleearth.
nasa.gov/view.php?
id=57723
Earth
• Earth is the 3rd planet from the sun.
• Earth’s orbital period is 365 ¼ days and it
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completes one rotation on its axis every day.
Earth has one large moon.
Earth has an extremely active geologic history.
Pangaea – a giant landmass of all the continents
– broke apart around 250 million years ago.
Earth
• Earth’s unique atmosphere and distance
from the sun allow water to exist in a
liquid state.
• Other planets are either too close or too
far away from the sun to maintain large
amounts of liquid water.
• Earth is the only known planet that has
the proper combination of water,
temperature, and oxygen to support life.
http://animalinformations.blogspot.com/2011/04/blue-whale-fish.html
http://www.fanpop.com/spots/marvin-themartian/images/739846/title/marvin-on-mars-photo
Mars
• Mars is the 4th planet from the sun.
• Mars is about 50% farther from the sun
than Earth is.
• Its orbital period is 687 days, and it
rotates on its axis every 24 hours and 37
minutes.
• Mars’s seasons are much like Earth’s
seasons because its axis tilts at nearly the
same angle that Earth does.
Mars
• Mars has a large system of deep canyons.
• Valles Marineris is a canyon that is as long as the U.S. is
wide – 4,500 km.
• Tharsis Montes is one of several volcanic regions on
Mars.
• The largest volcano on Mars is Olympus Mons, which is
nearly 24 km tall - three times as tall as Mount Everest.
• The base of Olympus Mons is 600 km across, about the
size of Nebraska.
• Scientists think that the volcano has grown so large
because Mars has no moving tectonic plates.
• A Viking landing craft detected two geological events
that produced seismic waves, called marsquakes, which
may indicate that volcanoes on Mars are active.
http://astrored.org/astrofotos/albums/Arte/
Marte/olympusmons15.jpg.html
http://starchild.gsfc.nasa.gov/docs/StarCh
ild/solar_system_level2/valles_marineris.
html
Mars
• The pressure and temperature of Mars’s atmosphere are
too low for water to exist as a liquid on Mars’s surface.
• Temperature ranges on Mars from 20°C (equator in
summer) to - 130°C (poles in winter).
• Several NASA spacecrafts have found evidence that
liquid water did exist on Mars’s surface in the past.
• Surface features on Mars are characteristic of erosion by
water.
• Although most of the water on Mars is trapped in polar
icecaps, it may also exist as permanent frost or as a
liquid just below the surface.
http://readtiger.com/wkp/en/Exploration_of_Mars
http://mars.jpl.nasa.gov/news/whatsnew/index.cfm?FuseAction=ShowNews&NewsID=1300
http://laist.com/2012/08/02/curi
ous_about_curiosity_griffith_ob.
php
http://lucidthoughts.com.au/wordpress/?attachment_id=336