The Solar SystemThe Solar System

Models of the Solar Models of the Solar SystemSystem

People have People have noticed the stars noticed the stars and objects in the and objects in the sky for 1000’s of sky for 1000’s of years.years.

There are two There are two models of how the models of how the universe was universe was thought to be thought to be structuredstructured

Geocentric ModelGeocentric Model

Geocentric Model-Geocentric Model- Earth is stationary Earth is stationary while objects in while objects in the sky move the sky move around it.around it.

Began with ancient Began with ancient Greeks.Greeks. Updated by Updated by

Egyptian Ptolemy Egyptian Ptolemy (accepted for (accepted for almost 1500 years).almost 1500 years).

Heliocentric ModelHeliocentric Model Heliocentric Model- Heliocentric Model-

Earth and other Earth and other planets revolve planets revolve around the sun.around the sun. Developed by Greek

astronomer Aristarchus (not accepted at the time).

Became accepted model in 1500’s when it was supported by Nicolaus Copernicus and Galileo Galilei.

Components of the Solar Components of the Solar SystemSystem

The planets orbit The planets orbit in an elliptical in an elliptical pattern (stretched pattern (stretched oval), not a circle.oval), not a circle.

Gravity and inertia Gravity and inertia combine to keep combine to keep the planets in orbit the planets in orbit around the sun.around the sun.

Astronomical UnitAstronomical Unit- - (AU) equals the (AU) equals the distance from the distance from the Earth to the Earth to the sun(150,000,000 km)sun(150,000,000 km) Pluto is 40 AU from Pluto is 40 AU from

the sun.the sun. The Oort Cloud is The Oort Cloud is

50,000+ AU from the 50,000+ AU from the sun (furthest points of sun (furthest points of the solar system)the solar system)

1 AU=150,000,000 km1 AU=150,000,000 km

25.2 Earth & Moon 25.2 Earth & Moon SystemSystem

Earth’s MoonEarth’s Moon Average Average

distance=384,000kmdistance=384,000km The moon has no The moon has no

atmosphere, which atmosphere, which explains the great explains the great variation in variation in temperatures.temperatures. Low=-180 Celsius/-310 FLow=-180 Celsius/-310 F High=130 Celsius/265 FHigh=130 Celsius/265 F

No atmosphere means No atmosphere means water cannot exist on water cannot exist on the moon (evaporation).the moon (evaporation).

The moon is a The moon is a natural satellite.natural satellite.

One of 96 moons in One of 96 moons in our solar system.our solar system. Earth has 1Earth has 1

1/6 the gravity on 1/6 the gravity on EarthEarth

Formation of the MoonFormation of the Moon

““Born” 4-5 billion Born” 4-5 billion years ago (4.6 years ago (4.6 billion).billion).

Formed from impact Formed from impact of Mars-sized of Mars-sized “planetesimal” on “planetesimal” on Earth.Earth.

Debris from both Debris from both objects melted objects melted together to form the together to form the Moon.Moon.

Surface FeaturesSurface Features

Lunar Highlands Lunar Highlands cover most of the cover most of the moons surface.moons surface.

Mountains up to Mountains up to 7500 meters 7500 meters (25,000 ft) tall.(25,000 ft) tall. Rilles- trench like Rilles- trench like

valleysvalleys

Surface FeaturesSurface Features

MariaMaria-low flat -low flat plains formed by plains formed by ancient lunar lava ancient lunar lava flows.flows. They cover 15% of They cover 15% of

the moons surface.the moons surface. Galileo thought the Galileo thought the

dark spots dark spots resembed seas, resembed seas, hence Maria.hence Maria.

Dark spots on moonDark spots on moon

Surface FeaturesSurface Features Craters-Craters-round round

depressions in the depressions in the surface caused by the surface caused by the impact of high-speed impact of high-speed meteroids.meteroids. Chunks of rock that Chunks of rock that

move through the solar move through the solar system.system.

Some formed by volcanic Some formed by volcanic action inside the moon.action inside the moon.

Up to 2500km (1,553 Up to 2500km (1,553 miles) across.miles) across.

These craters are These craters are evidence that the moon evidence that the moon is geologically dead.is geologically dead.

Phases of the MoonPhases of the Moon The moon does not The moon does not

produce its own light.produce its own light. You see the reflected You see the reflected

light from the sun.light from the sun. Phases-Phases-different different

shapes of the moon shapes of the moon visible from Earth.visible from Earth. These are caused due These are caused due

to the position of moon, to the position of moon, sun, and Earth.sun, and Earth.

Lunar Month-Lunar Month-the time it the time it takes the moon complete takes the moon complete a full cycle of phases.a full cycle of phases.

29.5 days29.5 days

The same side of the The same side of the moon always faces the moon always faces the Earth.Earth. Due to making one full Due to making one full

rotation (axis) while making rotation (axis) while making one full revolution around one full revolution around Earth.Earth.

Far side of moon has Far side of moon has different features-more different features-more craters, few maria, and craters, few maria, and thick crust.thick crust.

PhasesPhases

EclipsesEclipses Eclipses occur Eclipses occur

when the shadow when the shadow of one body in of one body in space, such as a space, such as a planet or moon, planet or moon, falls on another.falls on another. Only happen once Only happen once

in a while due to in a while due to varying ecliptic varying ecliptic planes.planes.

2 types:2 types: SolarSolar LunarLunar

TidesTides Tides are the regular Tides are the regular

rise and fall of the rise and fall of the oceans water.oceans water.

Tides are mainly Tides are mainly caused by caused by gravitational pull gravitational pull (differences) between (differences) between the moon and Earth.the moon and Earth. Depends on distanceDepends on distance

High and low tidesHigh and low tides Typically 2 of each a Typically 2 of each a

day per coast.day per coast.

Spring tide is when the Spring tide is when the change in high/low tide change in high/low tide is the greatest.is the greatest. Due to the moon, sun, Due to the moon, sun,

and Earth being in a and Earth being in a straight line.straight line.

New or full moonsNew or full moons

Neap tide is when the Neap tide is when the change in tides is change in tides is smallest.smallest. Moon and sun at right Moon and sun at right

angles.angles. 11stst or 3 or 3rdrd quarter moon. quarter moon.

The Inner Solar SystemThe Inner Solar System

The four inner planets are all The four inner planets are all relatively small and dense, and have relatively small and dense, and have rocky surfaces.rocky surfaces.

The terrestrial planets are planets The terrestrial planets are planets similar in structure to Earth.similar in structure to Earth.

Mercury, Venus, Earth, and Mars Mercury, Venus, Earth, and Mars are called the terrestrial planets.are called the terrestrial planets.

MercuryMercury Mercury is the smallest of Mercury is the smallest of

the terrestrial planets the terrestrial planets and the closest planet to and the closest planet to the sun.the sun.

Mercury is a dense planet Mercury is a dense planet with a very large iron with a very large iron core.core.

Mercury is geologically Mercury is geologically dead.dead.

There is no mantle There is no mantle convection within the convection within the planet and little erosion planet and little erosion on its surface.on its surface. Temperature can fluctuate Temperature can fluctuate

from 430 to -170 Celsius.from 430 to -170 Celsius.

VenusVenus Venus’s thick Venus’s thick

atmosphere is atmosphere is composed mostly of composed mostly of carbon dioxide, which carbon dioxide, which traps heat and raises traps heat and raises the planet’s the planet’s temperature.temperature.

Venus’s atmosphere Venus’s atmosphere contains droplets of contains droplets of sulfuric acid.sulfuric acid.

Average surface Average surface temperature 460 temperature 460 degrees.degrees.

MarsMars Mars is the most Mars is the most

Earthlike of all of the Earthlike of all of the planets. The weathering planets. The weathering of iron rock on its surface of iron rock on its surface gives the planet a reddish gives the planet a reddish color. This is why Mars is color. This is why Mars is called the “Red Planet.”called the “Red Planet.”

Olympus Mons is the Olympus Mons is the largest volcano in the largest volcano in the solar system.solar system. 3 times larger than Mt. 3 times larger than Mt.

everest.everest. Cleveland to D.C wide at its Cleveland to D.C wide at its

base.base.

AsteroidsAsteroids Beyond Mars is a Beyond Mars is a

region of small, rocky region of small, rocky bodies called bodies called asteroids that orbit asteroids that orbit the sun.the sun.

This region is referred This region is referred as the asteroid beltas the asteroid belt

Scientist now Scientist now hypothesize that hypothesize that asteroids are asteroids are remnants of the early remnants of the early solar system that solar system that never came together never came together to form a planetto form a planet

Outer PlanetsOuter Planets

The outer planets consist of the four gas giants. The outer planets consist of the four gas giants. Pluto, formerly considered a planet, was Pluto, formerly considered a planet, was reclassified as a dwarf planet in 2006.reclassified as a dwarf planet in 2006.

Gas giants have many moons, most of which Gas giants have many moons, most of which revolve in the same direction that the planets revolve in the same direction that the planets rotate. rotate.

Each of the gas giants is surrounded by rings. Each of the gas giants is surrounded by rings. A ring is a disk made of many small particles A ring is a disk made of many small particles of rock and ice in orbit around a planet. of rock and ice in orbit around a planet.

Rings are so close to the planet that Rings are so close to the planet that gravitational forces are very large, which may gravitational forces are very large, which may have prevented the ring particles from have prevented the ring particles from clumping together to form moons.clumping together to form moons.

JupiterJupiter Jupiter is the largest and most massive Jupiter is the largest and most massive

planet in our solar system.planet in our solar system. Sometimes storms occur at the

boundaries between these brown and white bands.

The Great Red Spot is a huge storm that rotates around its own center like a hurricane. It is caught between two bands of winds blowing in opposite directions.

Jupiter has 63 moons.

GiantsGiants

SaturnSaturn

Saturn, the second largest planet in the Saturn, the second largest planet in the solar system, is best known for its rings. solar system, is best known for its rings. The rings are made of particles of ice and The rings are made of particles of ice and

ice-coated rock.ice-coated rock. These particles are generally between a few These particles are generally between a few

micrometers and 10 meters across, with micrometers and 10 meters across, with most particles being snowball-sized. most particles being snowball-sized.

The rings are about 274,000 kilometers in The rings are about 274,000 kilometers in diameter, yet are only tens of meters thick.diameter, yet are only tens of meters thick.

UranusUranus A Tilted PlanetA Tilted Planet The most unusual The most unusual

characteristic of characteristic of Uranus is that it lies Uranus is that it lies nearly on its side. nearly on its side.

Uranus rotates in a Uranus rotates in a direction opposite to direction opposite to the direction of its the direction of its revolution around the revolution around the sun. Uranus’s rings and sun. Uranus’s rings and moons revolve about moons revolve about the same tilted axis. the same tilted axis.

NeptuneNeptune

Neptune is so far Neptune is so far from the sun that it from the sun that it takes a very long takes a very long time—165 Earth time—165 Earth years—for it to make years—for it to make one revolution. one revolution.

Neptune has about Neptune has about the same the same composition and is composition and is about the same size about the same size as Uranus.as Uranus.

Dwarf PlanetsDwarf Planets

In 2006, astronomers established a In 2006, astronomers established a new classification for certain objects new classification for certain objects in the solar system that share some, in the solar system that share some, but not all, of the characteristics of a but not all, of the characteristics of a planet.planet.

Pluto, which for many years had Pluto, which for many years had been considered the ninth and most been considered the ninth and most distant planet in the solar system, distant planet in the solar system, was reclassified as a dwarf planet. was reclassified as a dwarf planet.