Chapter Chapter 11 11

11.2 The Sun and the 11.2 The Sun and the Planetary SystemPlanetary System

Our solar system is full of planets, moon, asteroids, Our solar system is full of planets, moon, asteroids, andand

comets, all in motion around the comets, all in motion around the Sun.Sun. Most of these Most of these

components are separated by great distances. Eachcomponents are separated by great distances. Each

planet has its own distinct planet has its own distinct characteristics.characteristics. Comets, Comets, icyicy

debris, and dwarf planets travel at the outermost debris, and dwarf planets travel at the outermost

reaches of our solar system. reaches of our solar system.

Formation of the Solar SystemFormation of the Solar System Our solar system was formed more than Our solar system was formed more than

4.5 billion4.5 billion years ago. As the Sun burst into years ago. As the Sun burst into existence, the leftover material combined existence, the leftover material combined to form to form eight planetseight planets and numerous other and numerous other planetary bodies: planetary bodies: moons, asteroids, and moons, asteroids, and comets.comets. Closest to the Sun are Closest to the Sun are the inner the inner planetsplanets (terrestrial planets) and further (terrestrial planets) and further away are away are the outer planetsthe outer planets (gaseous (gaseous giants). giants).

The SUNThe SUN The sun contains more than The sun contains more than 99%99% of of

all the solar systems mass. The all the solar systems mass. The composition of our star is mainly composition of our star is mainly hydrogen gashydrogen gas, the most common , the most common element in space. The hydrogen in element in space. The hydrogen in the sun fuses with helium and the sun fuses with helium and radiates this energy outward. radiates this energy outward.

The SUNThe SUN The sun is a complex system of bubbling The sun is a complex system of bubbling

gases that occasionally send out gases that occasionally send out spectacular spectacular explosionsexplosions and violent and violent solar solar flares. flares. It has no solid surface but many It has no solid surface but many distinct features. distinct features.

Solar WindsSolar Winds Energetic gases in the Energetic gases in the coronacorona are ejected are ejected

in a sudden burst. When these high in a sudden burst. When these high energy particles rush past the Earth they energy particles rush past the Earth they create create “solar winds.”“solar winds.” These winds are These winds are deflected by the deflected by the magnetic fieldmagnetic field around around the earth’s poles. This is what causes our the earth’s poles. This is what causes our Northern LightNorthern Light shows. Sometimes these shows. Sometimes these winds can disrupt satellites and winds can disrupt satellites and temporarily knock out power supplies to temporarily knock out power supplies to Earth. Earth.

The The PLANETSPLANETS

To be consideredTo be considered

a planet the body musta planet the body must

orbitorbit one or more one or more stars,stars,

be large enough that itsbe large enough that its

own gravity holds it in aown gravity holds it in a

spherical shape,spherical shape, and be and be

the only body occupyingthe only body occupying

the the orbital path.orbital path.

MERCURYMERCURYo closestclosest planet to the planet to the SunSuno smallestsmallest,, slightly larger slightly larger than our moon than our moon o nono significant significant atmosphereatmosphereo extreme temperatures extreme temperatures 400400ooC to -183C to -183ooCCo changes in temperatureschanges in temperatures cause contraction and cause contraction and expansion of crust forming expansion of crust forming many many craters and crackscraters and cracks

VENUSVENUSo closestclosest to to EarthEarth o similar in composition to Earthsimilar in composition to Eartho atmosphere is almost all atmosphere is almost all carbon carbon

dioxidedioxideo thick clouds of thick clouds of sulphur dioxidesulphur dioxide

cover the planetcover the planeto planet has planet has volcanoesvolcanoes,, lava flowslava flows, ,

crackscracks and and riftsrifts

EARTHEARTHo blue planetblue planet,, 3 3rdrd rock from the Sun rock from the Suno suitable atmosphere and temperatures suitable atmosphere and temperatures o waterwater found in all 3 states (solid, liquid, found in all 3 states (solid, liquid,

gas)gas)o water covers nearly water covers nearly 3/43/4 of the entire of the entire

planetplaneto atmosphere is almost completely atmosphere is almost completely NN22 and and

OO22

MARSMARSo ““Red Planet” Red Planet” because of the because of the ironiron

content in soilcontent in soilo half the size of Earth but same surface half the size of Earth but same surface

areaareao has a volcano 3x the height of has a volcano 3x the height of Mt Mt

EverestEverest o has has 8 km deep canyon8 km deep canyon that stretches that stretches

from Vancouver to Torontofrom Vancouver to Torontoo thin atmosphere of thin atmosphere of carbon dioxidecarbon dioxideo has winds up to 900km/hr has winds up to 900km/hr o dust storms dust storms and and two polar ice capstwo polar ice caps

JUPITERJUPITERo largest planetlargest planet in solar in solar

systemsystemo gas giantgas gianto mass 2.5 times greater mass 2.5 times greater

than all planets combinedthan all planets combinedo great great “Red Spot” “Red Spot” (visible (visible

from Earth) is a storm from Earth) is a storm raging in clouds of raging in clouds of hydrogenhydrogen and and heliumhelium that forms the outer layersthat forms the outer layers

o has the shortest day of any has the shortest day of any planet, turning once on it’s planet, turning once on it’s axis every axis every 10 hrs10 hrs

SATURNSATURNo gas giant identified by the elaborate gas giant identified by the elaborate

system of system of ringsrings formed from ice particles formed from ice particleso ice ringsice rings are 250,000 km wide and as thin are 250,000 km wide and as thin

as 10mas 10mo planet is composed mainly of planet is composed mainly of hydrogen hydrogen

and heliumand helium

URANUSURANUSo fourth most massive planet, another fourth most massive planet, another

gas giant gas giant o Similar composition to Jupiter and Similar composition to Jupiter and

SaturnSaturno Also has a system of Also has a system of ringsrings made of made of iceice

and and dustdusto Blue colourBlue colour is from the is from the methane methane

gasgas in its atmosphere (methane in its atmosphere (methane absorbs red light) absorbs red light)

o it orbits differently than other planets it orbits differently than other planets because its axis is because its axis is tiltedtilted

NEPTUNENEPTUNEo outermost planetoutermost planet and 3and 3rdrd most most

massive massive o dark blue colourdark blue colour due to due to methanemethane

similar to Uranussimilar to Uranuso also has a also has a ring systemring system but is but is faintfainto when voyager 2 flew past the planet it when voyager 2 flew past the planet it

noticed a spot similar to Jupiter, which is noticed a spot similar to Jupiter, which is likely a likely a storm cloudstorm cloud

o Hubble telescope has discovered Hubble telescope has discovered another storm cloud near the northern another storm cloud near the northern hemispherehemisphere

The MOONThe MOON All planets All planets except Mercury and Venusexcept Mercury and Venus

have one or more have one or more orbiting orbiting companions.companions. Over Over 150150 moons have moons have been discovered orbiting planets in been discovered orbiting planets in our solar system. Astronomers call our solar system. Astronomers call these orbiting companions these orbiting companions “satellites.”“satellites.”

ASTEROIDSASTEROIDS AsteroidsAsteroids are small bodies that are are small bodies that are

leftover remainsleftover remains of the formation of of the formation of the solar system.the solar system.

Most asteroids orbit the sun in a Most asteroids orbit the sun in a band band between between MarsMars and and JupiterJupiter. They . They range in size from grains of sand to range in size from grains of sand to 1,000 km wide like 1,000 km wide like “CERES.”“CERES.”

COMETSCOMETS Comets are often referred to as Comets are often referred to as “dirty “dirty

snowballs.”snowballs.” They are composed of They are composed of iceice, , rockrock, and , and gasgas.. Space Space

probes have found that there is more rock than probes have found that there is more rock than

once thought. They originate from the once thought. They originate from the Kuiper Belt Kuiper Belt

and the and the Oort CloudOort Cloud. Once they get close enough . Once they get close enough

to the sun we can see the to the sun we can see the trailtrail of gas, ice and dust of gas, ice and dust

streaming behind. streaming behind.

Trans-Neptunian ObjectsTrans-Neptunian Objects

Anything that orbits the sun Anything that orbits the sun past Neptune are considered past Neptune are considered Trans-NeptunianTrans-Neptunian objects objects. . Scientists believe there are Scientists believe there are about about 23 objects23 objects orbiting in the orbiting in the Kuiper belt .Kuiper belt .

Some of these objects or dwarf Some of these objects or dwarf planets are:planets are: Pluto Pluto Ersis in the Kuiper belt Ersis in the Kuiper belt

Oort CloudOort Cloud At the farthest reaches of the At the farthest reaches of the

Suns gravitational influence is a Suns gravitational influence is a spherical cloud of small spherical cloud of small icy icy fragmentsfragments of debris called the of debris called the OortOort Cloud.Cloud. It is another source It is another source of of comets.comets. It is approximately It is approximately 1/41/4 the distance to the next closest the distance to the next closest star. star.

Section 11.2 Quiz

11.3 Measuring Distances 11.3 Measuring Distances in Spacein Space

Astronomical units are used to measure Astronomical units are used to measure distances within the solar system. distances within the solar system. Light yearsLight years are used to measure distances to other bodies are used to measure distances to other bodies far beyond our solar system. Distances far beyond our solar system. Distances measured from Earth to some bodies can be measured from Earth to some bodies can be determined by using determined by using triangulation triangulation and and parallaxparallax..

How BIG is SPACE? How BIG is SPACE?

Section 11.3 Quiz