The Planets

Terrestrial and Gas planetsTo be considered a planet

must orbit one or more starsits own gravity holds it in a spherical shapebe the only body occupying the orbital path

Terrestrial and Gas planetsLarge distances keep our solar

neighbourhood’s family of eight planets well separated from each other

Astronomical unit (AU), is equal to the average distance between the Sun and Earth, about 150 million km.

Earth is 1 AU from the Sun, while Jupiter is 5.27 AUs from the Sun.

Terrestrial planetsFour inner PlanetsHave rocky surfaces

Terrestrial planetsMercury

The closest planet to the Sun is also the smallest.slightly larger than our Moondifferences between night and daytemperatures

on its surface (ranging from 400°C to –183°C).

Terrestrial planetsVenus

often called Earth’s sister planetsimilar size and composition to

EarthVenus’s atmosphere is almost

completely carbon dioxidethe Magellan spacecraft

revealed that large portions of the planet arevery flat, while other areas have volcanoes, lava flows, and cracks called rifts.

Terrestrial planetsEarth

little blue planet, third from the Sun

only life yet discoveredonly place known to have

water in three phasesWater covers nearly three

quarters of Earth’s surfaceAtmosphere of nitrogen and

oxygen

Terrestrial planetsMars

called the red planethalf the size of EarthMars has a very thin

atmosphere of carbondioxide and can experience

winds of more than 900 km/h.

Mars has two polar ice caps made of frozen carbon dioxide

Outer PlanetsCalled Jovian PlanetsMuch Larger than the Inner PlanetsHave no real surface

Outer PlanetsJupiter

largest planet in the solar systemIt has a mass 2.5 times greater

than that of all the other planets combined

“Great Red Spot” a storm raging in the clouds of hydrogen and helium that form the planet’s outer layers ,as large as three Earths

the shortest day (10 hours)

Outer PlanetsSaturn

elaborate system of rings (from ice particles)

composed mainly of hydrogen and some helium

Outer PlanetsUranus

fourth most massive planetSimilar composition to

Jupiter and Saturn, including a ring system

blue colour from the methane gas in its atmosphere

unusual rotation in that it is flipped on its side

Outer PlanetsNeptune

outermost planetthird most massivecomposition is similar to

that of Uranus, and it has the same dark blue colour

Has a ring systemSome times has a large,

blue, Earth-size patch on Neptune’s surface likely a storm in the clouds

Terrestrial and Gas planets

QuestionsPage 411 #2,9,11