The Inner Planets

Objective 1 Draw a diagram of the solar system and label all the planets as either terrestrial or gas giants. 2 Compare the structure, composition, and atmosphere of the inner planets to include: density, shape, size, and unusual characteristics. 4 Examine the orbital paths of planets and other astronomical bodies (comets and asteroids). Examine the theories of geocentric and heliocentric models and Kepler’s laws of motion.

ES 4 The student will investigate and understand the characteristics of the Earth and the solar system. Key concepts include a. position of the Earth in the solar system c. characteristics of the Sun, planets and their moons, comets, meteors, and asteroids; and

Enduring Understanding The celestial bodies of our solar system differ as compared to Earth.

The Inner Planets The eight traditional planets of the Solar System can be grouped into two main categories according to their basic properties. The four closest planets to the Sun are called the terrestrial planets. Terrestrial planets are close to the size of Earth Terrestrial planets all have solid, rocky surfaces***

The Inner Planets Mercury Closest*** planet to the Sun No moons Very slow rotation Very little atmosphere consisting of oxygen and sodium Daytime surface temp is 427 C Nighttime temp falls to -173 C

Surface of Mercury Covered with craters and plains (similar to Luna)

Surface of Mercury Plains are smooth with very few craters (similar to the maria) Planetwide system of cliffs called scarps

Surface of Mercury Possibly come from a shrinking crust fracturing

Interior of Mercury Believed to be a high density iron-nickel core comprising about 42 percent of the volume Possibly what Earth would look like if the crust and mantle were removed Outer layers may have been lost in a collision

Venus Brightest object **in the nighttime sky No moons Highest albedo of any planet No moons Very slow rotation (1Venus day = 243 Earth Days) Clockwise spin (different than most solar system)****

Venus’ Atmosphere Average temp is 464 C (The hottest planet*****) Composed of CO2*** (96.5%) and N (3.5%) Pressure is 90 times Earth’s Clouds are made of Sulfuric acid Strong greenhouse effect****

Surface of Venus Evidence of recent Lava flows and few impact craters Little evidence of current tectonic activity and no plates

Mercury and Venus (labelled)

Mars Called the red planet** because of the high soil iron content** Two irregularly shaped moons: Phobos and Demios which are probably captured asteroids

Mars Two irregularly shaped moons: Phobos and Demios which are probably captured asteroids

Mars’ Atmosphere Similar to Venus, but far less dense therefore lower pressure Weak greenhouse effect Thin, but turbulent; constant winds drive dust storms that last for weeks at a time

Surface of Mars Southern hemisphere is a heavily cratered highland region resembling the highlands on the Moon Northern hemisphere is sparsely cratered plains with four gigantic shield volcanoes

Surface of Mars Olympus Mons****** is the largest volcano in the Solar System it is three times higher than Mt. Everest and covers an area the size of Colorado

Surface of Mars Valles Marineris*** is a 4,000 km canyon running along the Martian equator

Surface of Mars There is extensive evidence of past areas of liquid water, dry river and lake beds and the polar caps are frozen CO2 with water ice beneath “This is a Nice planet to visit, but I would not want to live There.”

Surface of Mars Mar’s Interior is Iron and Nickel and probably solid since Mars has no magnetic field