EARTH & SPACE SCIENCEEARTH & SPACE SCIENCE

Chapter 27 Planets of the Chapter 27 Planets of the Solar SystemSolar System

27.3 The Inner Planets27.3 The Inner Planets

27.3 The Inner Planets 27.3 The Inner Planets ObjectivesObjectives

• Identify the basic characteristics of Identify the basic characteristics of the inner planets.the inner planets.

• Compare the characteristics of the Compare the characteristics of the inner planets.inner planets.

• Summarize the features that allow Summarize the features that allow Earth to sustain life.Earth to sustain life.

IntroductionIntroduction• The inner planets – those closest to the sun – The inner planets – those closest to the sun –

are Mercury, Venus, Earth, and Mars.are Mercury, Venus, Earth, and Mars.

• The inner planets are also called terrestrial The inner planets are also called terrestrial planets because they are made mostly of solid planets because they are made mostly of solid rock and have metallic cores.rock and have metallic cores.

• The number of moons of the terrestrial planets The number of moons of the terrestrial planets can vary from zero to two.can vary from zero to two.

• Impact craters on the terrestrial planets are Impact craters on the terrestrial planets are evidence of collisions with other objects in evidence of collisions with other objects in space.space.

http://askville.amazon.com/largest-densest-rocky-planets-solar-system/AnswerViewer.do?requestId=8907806

http://www.wallpaper-zone.de/wallpapers-queen/wallpaper-6,486,010.html

MercuryMercury

• Mercury is the closest planet to the sun and Mercury is the closest planet to the sun and orbits the sun every 88 days.orbits the sun every 88 days.

• Mercury rotates once on its axis every 59 days.Mercury rotates once on its axis every 59 days.• The surface is characterized with many craters The surface is characterized with many craters

and a line of cliffs hundreds of kilometers long.and a line of cliffs hundreds of kilometers long.• The cliffs may be the result of the molten core The cliffs may be the result of the molten core

cooling and shrinking causing wrinkles in the cooling and shrinking causing wrinkles in the crust.crust.

• Lack of dense atmosphere and the planets slow Lack of dense atmosphere and the planets slow rotation contribute to the extreme temperature rotation contribute to the extreme temperature change (427°C – day; -173°C – night).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

VenusVenus

• Venus is the second Venus is the second planet from the sun planet from the sun and has an orbital and has an orbital period of 225 days.period of 225 days.

• Venus completes one Venus completes one full rotation every full rotation every 243 days.243 days.

• Venus and Earth are Venus and Earth are almost the same almost the same size, mass, and size, mass, and density.density.

http://planetfacts.org/planet-venus-facts/

VenusVenus• The atmospheric The atmospheric

pressure on Venus is pressure on Venus is about 90 times that of about 90 times that of Earth.Earth.

• The high concentration The high concentration of COof CO22 (96%) and its (96%) and its proximity to the Sun proximity to the Sun have resulted in have resulted in runaway greenhouse runaway greenhouse effect.effect.

• Average surface Average surface temperature for Venus temperature for Venus reaches 464°C.reaches 464°C.

http://www.herebeanswers.com/2011/07/why-is-there-runaway-greenhouse-effect.html

VenusVenus

• The sulfur dioxide droplets The sulfur dioxide droplets in the upper atmosphere of in the upper atmosphere of Venus reflect much Venus reflect much sunlight.sunlight.

• Venus appears to be the Venus appears to be the brightest object in the sky brightest object in the sky except for the sun and except for the sun and moon.moon.

• Because Venus appears Because Venus appears near the sun, it is visible near the sun, it is visible from Earth only in the early from Earth only in the early morning or evening – morning or evening – “morning star” or the “morning star” or the “evening star”.“evening star”.http://fineartamerica.com/featured/

evening-star-a3551.html

VenusVenus

• In the 1970s, the Soviet In the 1970s, the Soviet Union sent six probes to Union sent six probes to explore the surface of explore the surface of Venus.Venus.

• The probes transmitted The probes transmitted surface images of a rocky surface images of a rocky landscape, a smooth plain, landscape, a smooth plain, and some rocks.and some rocks.

• The surface of Venus is The surface of Venus is mostly basalt and granite.mostly basalt and granite.

• In the 1990s, Magellan In the 1990s, Magellan (United States) satellite (United States) satellite collected atmospheric data collected atmospheric data and bounced radio waves and bounced radio waves off Venus to produce radar off Venus to produce radar images of Venus’s surface.images of Venus’s surface.

http://exoplanet.as.arizona.edu/~lclose/teaching/a202/lect16.html

http://spacechronology.com/1990s.html

VenusVenus

• Scientists discovered landforms such as Scientists discovered landforms such as mountains, volcanoes, lava plains, and sand dunes.mountains, volcanoes, lava plains, and sand dunes.

• Volcanoes and lava plains are the most common Volcanoes and lava plains are the most common features on Venus. features on Venus.

• Maat Mons is Venus’s highest volcano, at an Maat Mons is Venus’s highest volcano, at an elevation of 3 km.elevation of 3 km.

• The surface of Venus is also somewhat cratered.The surface of Venus is also somewhat cratered.• All of the caters are of the same age and are All of the caters are of the same age and are

surprisingly young.surprisingly young.• Unlike Earth’s surface which is constantly changing Unlike Earth’s surface which is constantly changing

because of the motion of tectonic plates, Venus’s because of the motion of tectonic plates, Venus’s surface undergoes periodic resurfacing as a result surface undergoes periodic resurfacing as a result of massive volcanic activity.of massive volcanic activity.

http://tvlistings.zap2it.com/tv/3rd-rock-from-the-sun/photo-gallery-detail/EP00163817/293950

http://visibleearth.nasa.gov/view.php?id=57723

EarthEarth

• Earth is the 3Earth is the 3rdrd planet from the sun. planet from the sun.

• Earth’s orbital period is 365 ¼ days and it Earth’s orbital period is 365 ¼ days and it completes one rotation on its axis every day.completes one rotation on its axis every day.

• Earth has one large moon.Earth has one large moon.

• Earth has an extremely active geologic Earth has an extremely active geologic history.history.

• Pangaea – a giant landmass of all the Pangaea – a giant landmass of all the continents – broke apart around 250 million continents – broke apart around 250 million years ago.years ago.

EarthEarth

• Earth’s unique atmosphere and Earth’s unique atmosphere and distance from the sun allow water to distance from the sun allow water to exist in a liquid state. exist in a liquid state.

• Other planets are either too close or Other planets are either too close or too far away from the sun to maintain too far away from the sun to maintain large amounts of liquid water.large amounts of liquid water.

• Earth is the only known planet that has Earth is the only known planet that has the proper combination of water, the proper combination of water, temperature, and oxygen to support temperature, and oxygen to support life.life.

http://animalinformations.blogspot.com/2011/04/blue-whale-fish.html

http://www.fanpop.com/spots/marvin-the-martian/images/739846/title/marvin-on-mars-photo

MarsMars

• Mars is the 4Mars is the 4thth planet from the sun. planet from the sun.• Mars is about 50% farther from the sun Mars is about 50% farther from the sun

than Earth is.than Earth is.• Its orbital period is 687 days, and it Its orbital period is 687 days, and it

rotates on its axis every 24 hours and rotates on its axis every 24 hours and 37 minutes.37 minutes.

• Mars’s seasons are much like Earth’s Mars’s seasons are much like Earth’s seasons because its axis tilts at nearly seasons because its axis tilts at nearly the same angle that Earth does. the same angle that Earth does.

MarsMars

• Mars has a large system of deep canyons.Mars has a large system of deep canyons.• Valles Marineris is a canyon that is as long as the U.S. is Valles Marineris is a canyon that is as long as the U.S. is

wide – 4,500 km.wide – 4,500 km.• Tharsis Montes is one of several volcanic regions on Tharsis Montes is one of several volcanic regions on

Mars. Mars. • The largest volcano on Mars is Olympus Mons, which is The largest volcano on Mars is Olympus Mons, which is

nearly 24 km tall - three times as tall as Mount Everest. nearly 24 km tall - three times as tall as Mount Everest. • The base of Olympus Mons is 600 km across, about the The base of Olympus Mons is 600 km across, about the

size of Nebraska.size of Nebraska.• Scientists think that the volcano has grown so large Scientists think that the volcano has grown so large

because Mars has no moving tectonic plates.because Mars has no moving tectonic plates.• A A VikingViking landing craft detected two geological events landing craft detected two geological events

that produced seismic waves, called that produced seismic waves, called marsquakesmarsquakes, which , which may indicate that volcanoes on Mars are active.may indicate that volcanoes on Mars are active.

http://starchild.gsfc.nasa.gov/docs/StarChild/solar_system_level2/valles_marineris.html

http://astrored.org/astrofotos/albums/Arte/Marte/olympusmons15.jpg.html

MarsMars

• The pressure and temperature of Mars’s The pressure and temperature of Mars’s atmosphere are too low for water to exist as a atmosphere are too low for water to exist as a liquid on Mars’s surface.liquid on Mars’s surface.

• Temperature ranges on Mars from 20°C (equator in Temperature ranges on Mars from 20°C (equator in summer) to - 130°C (poles in winter).summer) to - 130°C (poles in winter).

• Several NASA spacecrafts have found evidence that Several NASA spacecrafts have found evidence that liquid water did exist on Mars’s surface in the past. liquid water did exist on Mars’s surface in the past.

• Surface features on Mars are characteristic of Surface features on Mars are characteristic of erosion by water.erosion by water.

• Although most of the water on Mars is trapped in Although most of the water on Mars is trapped in polar icecaps, it may also exist as permanent frost polar icecaps, it may also exist as permanent frost or as a liquid just below the surface.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/curious_about_curiosity_griffith_ob.php

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