OUR SOLAR SYSTEM

Chapter 2By Mrs. Shaw

WHAT IS OUR SOLAR SYSTEM MADE OF?

Our solar system is made of planets, moons, comets, asteoroids, man-made satellites, and our sun.

Lesson 1: The Solar System

GEOCENTRIC VS. HELIOCENTRIC MODELS OF OUR SOLAR SYSTEM

Scientists used to think that the earth was the center of our solar system. (Geocentric model)

As technology advanced and we were able to see and explore our solar system we discovered that the sun is actually the center of our solar system. (Heliocentric model) Heliocentric

= Sun at center

Geocentric = Earth at center

REVIEW OF PLANETARY MOTION TERMS

Period of rotation: the time it takes for an object to complete one full spin or rotation.

Period of revolution: the time it takes for an object to travel once around the sun.

Planets also move in an elliptical orbit around the sun.

WHAT KEEPS THE PLANETS ORBITING THE SUN?

• Universal law of gravitation: every object with mass has a gravitational attractive force to every other object with mass.

• Gravity depends on ; distance and mass.

• Therefore, the gravitational attraction of the sun with each of the planets is what keeps them orbiting the sun.

HOW DO WE MEASURE DISTANCES IN SPACE?

Distances in space are so large that we have a special unit of measurement for them called an astronomical unit.

One astronomical unit (au) is equal to the distance from the earth to the sun.

Notice on the chart how that distance relates to other distances in space.

1 AU = 149,598,000 km

WHY ARE THE FOUR INNER PLANETS CALLED THE TERRESTRIAL PLANETS?

The four inner planets in our solar system, Mercury, Venus, Earth, and Mars, are made of rocks and metals, and they all have a solid inner core.

Lesson 2: The Inner Planets

FACTS ABOUT MERCURY

GRAVITATIONAL FORCE: 37% OF EARTH’S GRAVITY

DISTANCE FROM THE SUN:0.39 AU OR 57,910,000 KM

MASS / DIAMETER: 5.5% OF EARTH’S MASS AND 38.3% OF EARTH’S DIAMETER

MOVEMENT: ROTATION 59 DAYS AND 88 REVOLUTION DAYS

TEMPERATURE:EXTREMES FROM 450 DEGREES CELSIUS ON SIDE FACING SUNTO -170 DEGREES CELSIUS ON SIDE NOT FACING SUN.

ATMOSPHERIC CONDITIONS: NO ATMOSPHERE, ROCKY CRATERED SURFACE WITH NO MOONS.

FACTS ABOUT VENUSGRAVITATIONAL FORCE:88% OF EARTH’S GRAVITY

DISTANCE FROM THE SUN:0.72 AU OR 108,210,000 KM

MASS / DIAMETER: 81.5% OF EARTH’S MASS AND 95% OF EARTH’S DIAMETER

MOVEMENT: ROTATION 244 DAYS AND REVOLUTION 225 DAYS

TEMPERATURE: AVERAGE TEMP 460 DEGREES CELSIUS (HOTTEST PLANET IN SOLAR SYSTEM DUE TO GREENHOUSE EFFECT )

ATMOSPHERIC CONDITIONS: VERY THICK ATMOSPHERE THAT IS ABOUT 90 TIMES GREATER THAN EARTH’S. SURFACE IS 80% SOLID LAVA. NO MOONS.

FACTS ABOUT EARTH

GRAVITATIONAL FORCE:100% = 9.80665 M/S2

DISTANCE FROM THE SUN:1 AU OR 149,600,000 KM

MASS / DIAMETER: 100% MASS = 5.9736 X 1024 KG AND 12,742 KM DIAMETER

MOVEMENT: ROTATION 24 HOURS AND REVOLUTION 365 DAYS

TEMPERATURE: PERFECT TEMP FOR LIQUID WATER TO EXIST. HIGHEST TEMP 57.8 DEGREES CELSIUS AND LOWEST IS -89.2 DEGREES CELSIUS

ATMOSPHERIC CONDITIONS: MIXTURE OF GASES AND WATER VAPOR MAKE UP ATMOSPHERE.

FACTS ABOUT MARS

GRAVITATIONAL FORCE: 38% OF EARTH’S GRAVITY

DISTANCE FROM THE SUN:1.52 AU OR 227,920,000 KM

MASS / DIAMETER: 10.7% EARTH’S MASS AND 53.2% EARTH’S DIAMETER

MOVEMENT: ROTATION 24.6 HOURS AND REVOLUTION 1.88 YEARS

TEMPERATURE: RANGE FROM -125 DEGREES CELSIUS AT POLES AND 20 DEGREES CELSIUS AT EQUATOR.

ATMOSPHERIC CONDITIONS: 95% CARBON DIOXIDE, THIN AND LESS DENSE THAN EARTH. SURFACE IS MOSTLY IRON OXIDE WHICH GIVES IT THE REDDISH COLOR.

WHY ARE THE FOUR OUTER PLANETS KNOWN AS THE GAS GIANTS?

THEY ARE PRIMARILY MADE OF HYDROGEN AND HELIUM GASES.THEY ALSO HAVE STRONG GRAVITATIONAL FORCES DUE TO THEIR HUGE SIZES.

Lesson 3: The Outer Planets

These forces apply tremendous pressure and cause the gases to change to liquids. Most have a thick gas and liquid covering a small solid core.

FACTS ABOUT JUPITER

Close up picture of Great Red Spot – large storm of swirling gases

GRAVITATIONAL FORCE:264% OF EARTH’S GRAVITY

DISTANCE FROM THE SUN:5.20 AU OR 778,570,000 KM

MASS / DIAMETER: 318 TIMES EARTH’S MASS AND 11.2 TIMES EARTH’S DIAMETER

MOVEMENT: ROTATION 9.9 HOURS AND REVOLUTION 11.9 YEARS

TEMPERATURE: ??? THOUGHT TO BE FROM 20 DEGREES CELSIUS AT COOLEST AND ABOUT 35,500 DEGREES CELSIUS AT THE CORE.

ATMOSPHERIC CONDITIONS: 90% HYDROGEN AND 10 % HELIUM AND ABOUT 1,000KM DEEP

Jupiter has at

least 63 moons!

FACTS ABOUT SATURN

GRAVITATIONAL FORCE:115% OF EARTH’S GRAVITY

DISTANCE FROM THE SUN:9.58 AU OR 1,433,530,000 KM

MASS / DIAMETER: 95 TIMES EARTH’S MASS AND 9.4 TIMES EARTH’S DIAMETER

MOVEMENT: ROTATION 10.6 HOURS AND REVOLUTION 29.7 YEARS

TEMPERATURE: ??? THOUGHT TO BE FROM -175 DEGREES CELSIUS AT COOLEST AND ABOUT 11,700 DEGREES CELSIUS AT THE CORE.

ATMOSPHERIC CONDITIONS: 90% HYDROGEN AND 10 % HELIUM AND ABOUT 1,000KM DEEP BUT IT IS ALSO THE LEAST DENSE PLANET.

Saturn has at

least 60

moons!

7 rings made of ice surround Saturn.

Also has

massive wind

storms!

FACTS ABOUT URANUS

GRAVITATIONAL FORCE:93% OF EARTH’S GRAVITY

DISTANCE FROM THE SUN:19.20 AU OR 2,872,460,000 KM

MASS / DIAMETER: 14.5 TIMES EARTH’S MASS AND . 4.0 TIMES EARTH’S DIAMETER

MOVEMENT: ROTATION 17.4 HOURS AND REVOLUTION 84.3 YEARS

TEMPERATURE: COLDEST PLANET IN SOLAR SYSTEM REACHING -225 DEGREES CELSIUS AND A CORE OF 4,737 DEGREES CELSIUS.

ATMOSPHERIC CONDITIONS: DEEP ATMOSPHERE MADE OF HYDROGEN, HELIUM, AND METHANE.

MOVEMENT

Uranus has moons.

FACTS ABOUT NEPTUNE

Close up picture of dark spot viewed by Voyager in 1989 but gone 5 years later.

GRAVITATIONAL FORCE:122% OF EARTH’S GRAVITY

DISTANCE FROM THE SUN:30.05 AU OR 4,495,060,000 KM

MASS / DIAMETER: 17.1 TIMES EARTH’S MASS AND .3.9 TIMES EARTH’S DIAMETER

MOVEMENT: ROTATION 16.1 HOURS AND REVOLUTION 165.2 YEARS

TEMPERATURE: UPPER ATMOSPHERE IS -218 DEGREES CELSIUS BUT IT’S CORE IS AROUND 7,000 DEGREES CELSIUS.

ATMOSPHERIC CONDITIONS: LIKE URANUS IT HAS A DEEP ATMOSPHERE MADE OF HYDROGEN, HELIUM, AND METHANE.

Neptune has 13 moons and a faint, dark ring system.

WHAT IS THE DIFFERENCE BETWEEN A PLANET AND A DWARF PLANET?

THE DEFINITION OF PLANET SET IN 2006 BY THE INTERNATIONAL ASTRONOMICAL UNION (IAU) STATES THAT, IN THE SOLAR SYSTEM, A PLANET IS A CELESTIAL BODY WHICH:

– IS IN ORBIT AROUND THE SUN,– HAS SUFFICIENT MASS TO ASSUME

HYDROSTATIC EQUILIBRIUM (A NEARLY ROUND SHAPE), AND

– HAS "CLEARED THE NEIGHBORHOOD" AROUND ITS ORBIT.

A NON-SATELLITE BODY FULFILLING ONLY THE FIRST TWO OF THESE CRITERIA IS CLASSIFIED AS A "DWARF PLANET".

THE REASON THAT PLUTO FAILS AS A MAJOR PLANET IS BECAUSE IT HAS NOT "CLEARED ITS NEIGHBORHOOD." PLUTO'S ORBIT CROSSES THAT OF NEPTUNE, A VASTLY LARGER BODY. PLUTO ALSO SHARES ITS ORBIT WITH THE KUIPER BELT, A SWATH OF SMALL ICY BODIES BEYOND NEPTUNE.

Lesson 4: Other objects in the Solar System

WHAT IS THE DIFFERENCE BETWEEN A COMET, ASTEROID, AND METEOR?

• Asteroid: A small, inactive body, composed of rock, carbon or metal, which is orbiting the sun.

•Comet: a small, sometimes active object, which is composed of dirt and ices. Comets are characterized by dust and gas tails when in proximity to the sun.

•Meteoroid: a small particle from an asteroid or comet orbiting the sun.

•Meteor: a meteoroid that is observed as it burns up in the earth's atmosphere – (a shooting star).

•Meteorite: a meteoroid that survives its passage through the earth's atmosphere and impacts the earth's surface. 

Asteroid

Comet