Models of the Solar System

Geocentric Model - Earth is considered to be the center and everything else revolves around it.

Heliocentric Model –The sun is the center of the solar system.

Copernicus proposed that the Moon revolves around Earth, and that the apparent motion of the planets, stars, and Sun is due to Earth’s rotation.

Galileo Galilei found evidence supporting Copernicus’ theory and also saw moons in orbit around Jupiter.

He concluded that the Sun is the center of the solar system.

Copernicus and Galileo thought that the orbits of the planets were circular, but a German mathematician, Johannes Kepler, discovered that they travel in ellipses, not circles.

OUR SOLAR SYSTEMOUR SOLAR SYSTEM

SUMMARYSUMMARYEarly astronomers thought Early astronomers thought

the Sun, planets, and stars the Sun, planets, and stars orbited a stationary Earth. orbited a stationary Earth.

CopernicusCopernicus suggested that suggested that the Sun was the center of the Sun was the center of the solar system. the solar system.

KeplerKepler demonstrated that demonstrated that each planet orbited the each planet orbited the Sun in an elliptical pattern. Sun in an elliptical pattern.

OUR SOLAR SYSTEMOUR SOLAR SYSTEM My Very Excellent Mother My Very Excellent Mother

Just Served Us Nine Just Served Us Nine ((Pizzas)Pizzas)

Solar System—The sun Solar System—The sun and all the objects that and all the objects that orbit around itorbit around it

Planets reflect light, and Planets reflect light, and stars emit light.stars emit light.

Inner Terrestrial PlanetsInner Terrestrial Planets

MercuryMercuryExtreme Extreme

TemperaturesTemperaturesSmallestSmallestClosest to the Closest to the

sunsun

Inner Terrestrial PlanetsInner Terrestrial Planets

VenusVenus Second planet from the sun.Second planet from the sun. Similar in size to EarthSimilar in size to Earth Extremely thick, dense Extremely thick, dense

atmosphereatmosphere Hottest average temperaturesHottest average temperatures Named after the goddess of Named after the goddess of

lovelove Sometimes called the morning Sometimes called the morning

star or the evening starstar or the evening star

Inner Terrestrial PlanetsInner Terrestrial Planets

EarthEarth Third planet from the Third planet from the

sun.sun. Water can exist as a Water can exist as a

solid, liquid, and a gas.solid, liquid, and a gas. Only planet not named Only planet not named

after a character in after a character in Roman mythologyRoman mythology

Inner Terrestrial PlanetsInner Terrestrial Planets

MarsMars Fourth planet from the Fourth planet from the

sunsun Commonly called the Commonly called the

Red PlanetRed Planet Has the “sphinx face” Has the “sphinx face”

and “pyramids”and “pyramids” Has polar ice capsHas polar ice caps Atmosphere is thinner Atmosphere is thinner

than Earth’s.than Earth’s. Two moons, Phobos Two moons, Phobos

and Deimosand Deimos

Outer “Gas Giants”Outer “Gas Giants”The inner and outer The inner and outer

planets are divided by planets are divided by an asteroid belt.an asteroid belt.

All of the gaseous outer All of the gaseous outer planets have rings planets have rings and moons.and moons.

Outer “Gas Giants”Outer “Gas Giants”JUPITERJUPITER Fifth planet from the Fifth planet from the

SunSun Largest planet in our Largest planet in our

solar systemsolar system Great red spot that is Great red spot that is

a massive hurricanea massive hurricane Has more than 60 Has more than 60

moonsmoons

Outer “Gas Giants”Outer “Gas Giants”

SATURNSATURN Sixth planet from the Sixth planet from the

Sun.Sun. Spectacular icy Spectacular icy

ringsrings Second largest Second largest

planet in the solar planet in the solar system.system.

Outer “Gas Giants”Outer “Gas Giants”URANUSURANUS Seventh planet from Seventh planet from

the Sun.the Sun. Planet rotation is on Planet rotation is on

its sideits side Blue in color due to Blue in color due to

methane gasmethane gas Has 27 moonsHas 27 moons

Outer “Gas Giants”Outer “Gas Giants”NEPTUNENEPTUNE Eighth planet from the Eighth planet from the

Sun.Sun. Blue in color due to Blue in color due to

methane gasmethane gas Large blue spot which Large blue spot which

is a hurricane-like is a hurricane-like stormstorm

Outer “Gas Giants”Outer “Gas Giants”PLUTOPLUTO No longer considered No longer considered

to be a planet due to to be a planet due to highly elliptical orbit highly elliptical orbit and composition.and composition.

Does not have rings, Does not have rings, and is not and is not predominately predominately gaseous only.gaseous only.

Meteoroid, meteor or meteorite?Meteoroid, meteor or meteorite?A A meteoroidmeteoroid is interplanetary is interplanetary

material that falls toward Earth material that falls toward Earth and enters Earth’s and enters Earth’s atmosphere. When a falling atmosphere. When a falling meteoroid burns up in Earth’s meteoroid burns up in Earth’s atmosphere and produces a atmosphere and produces a streak of light, it is called a streak of light, it is called a meteor.meteor. If the meteoroid does If the meteoroid does not completely burn up, part of not completely burn up, part of it will collide with the ground, it will collide with the ground, and it is called a and it is called a meteoritemeteorite..

CometsCometsCometsComets are small, icy are small, icy

bodies that have bodies that have highly eccentric orbits highly eccentric orbits around the Sun. around the Sun. Some comets are Some comets are periodic, such as periodic, such as Halley’s comet, which Halley’s comet, which comes every 76 years comes every 76 years (expected again in (expected again in 2061).2061).