the nature of our solar system the nature of our solar system

The Nature of OurSolar System

The Nature of OurSolar System

8.8.

SUNSUNSUNSUN

MercuryMercury

VenusVenus

EarthEarthMarsMars

JupiterJupiter SaturnSaturn

UranusUranusNeptuneNeptune

Asteroid BeltAsteroid Belt

Outer planetsJovian planets

Gas planets

Inner planetsTerrestrial planets

SUNSUN

Astronomical Unit (AU)Astronomical Unit (AU)• distance from the sun to earthdistance from the sun to earth

1 astronomical unit1 astronomical unit

93 million miles93 million miles

So, how many miles is 3 AU?So, how many miles is 3 AU?3 X 93 million = 279,000,000 miles3 X 93 million = 279,000,000 miles

I I I I the planets. the planets.

I will get an A on my exams and quizzes.I will get an A on my exams and quizzes.

Discuss with a friend:Discuss with a friend:

1.Write down the order of planets. Know them backwards and forwards.

2. Define an astronomical unit.

1.Write down the order of planets. Know them backwards and forwards.

2. Define an astronomical unit.

How big do you think the EarthHow big do you think the Earthis comparedis compared

with other celestial bodieswith other celestial bodies??

The sun represents 99.85% The sun represents 99.85% of the solar system mass.of the solar system mass.

The sun represents 99.85% The sun represents 99.85% of the solar system mass.of the solar system mass.

Our sun (star) is compared to otherOur sun (star) is compared to otherstars in the universe.stars in the universe.

Our sun (star) is compared to other stars in the universe.

Our sun (star) is compared to other stars in the universe.

What beliefs existed about our solar system?What beliefs existed about our solar system?Ancient astronomy:Ancient astronomy:

The Early Greeks:The Early Greeks:

• 600 BC – 150 AD600 BC – 150 AD• used geometry / trigonometry principlesused geometry / trigonometry principles

• presented the “geocentric” modelpresented the “geocentric” model• all heavenly bodies move around all heavenly bodies move around the earth – the earth is motionlessthe earth – the earth is motionless

• presented by Claudius Ptolemy – presented by Claudius Ptolemy – The The AlmagestAlmagest, 141 AD, 141 AD

The solar system was viewed as a geocentric model.The solar system was viewed as a geocentric model.• based on planetary motion observationsbased on planetary motion observations

Earth-centeredEarth-centered

GeoGeocentriccentric

EarthEarth centercenter

Proposed byProposed byPtolemyPtolemy

RetrogradeRetrogrademotionmotion

Geocentric modelGeocentric modelproposed byproposed by

PtolemyPtolemyRetrogradeRetrogrademotionmotion

I I astronomy. astronomy.



1. Describe the geocentric model.

2. What is retrograde motion?

3. Describe what an observer would see during a planet’s retrograde motion.

1. Describe the geocentric model.

2. What is retrograde motion?

3. Describe what an observer would see during a planet’s retrograde motion.

The Birth of Modern Astronomy:The Birth of Modern Astronomy:The breakthrough from philosophical and The breakthrough from philosophical and

religious views:religious views:

Nicholas CopernicusNicholas Copernicus (1473 – 1543) (1473 – 1543)

• Concluded the earth is another planetConcluded the earth is another planet

• Daily motions of earth can be explained byDaily motions of earth can be explained by a rotating eartha rotating earth

• Developed the heliocentric model – the sun-Developed the heliocentric model – the sun- centered earthcentered earth

• Used circles as orbital paths for each planetUsed circles as orbital paths for each planet

The Copernican view of the solar systemThe Copernican view of the solar system

Sun-centeredSun-centered

heliocentriccentric

SunSun centercenter

Proposed byProposed byCopernicusCopernicus

SUNSUN

EarthEarth

I I solar system history. solar system history.


1.How does geocentric retrograde motion compare to heliocentric retrograde motion?

2. Describe the differences between the geocentric and heliocentric solar system models.

1.How does geocentric retrograde motion compare to heliocentric retrograde motion?

2. Describe the differences between the geocentric and heliocentric solar system models.

The Birth of Modern AstronomyThe Birth of Modern Astronomy

Tycho BraheTycho Brahe (1546 – 1601) (1546 – 1601)• Danish nobility – CopenhagenDanish nobility – Copenhagen

• Designed and built “pointers” that accuratelyDesigned and built “pointers” that accurately predicted the positions of planets in the skypredicted the positions of planets in the sky

• DID NOTDID NOT believe in the heliocentric model believe in the heliocentric model• Stars in the background should be Stars in the background should be shifting every six months?shifting every six months?

• The stellar parallax conceptThe stellar parallax concept “ “thumb demonstration”thumb demonstration”

Stellar ParallaxStellar Parallax

How far is far? - Astronomical distances?How far is far? - Astronomical distances?

Using parallax

• the “slight” shifting of a star due to the orbit of the earth around our sun

6 months later

From earth theobserved star is shifted relative tothe background stars.

Close stars willshift at larger angles.

Distant stars will shift at smaller angles.

I I Tycho Brahe. Tycho Brahe.


1.What is Tycho Brahe’s contribution to our understanding of the solar system?

2. 2. Explain the concept of stellar parallax.

3. How does the “thumb” test show stellar parallax?

1.What is Tycho Brahe’s contribution to our understanding of the solar system?

2. 2. Explain the concept of stellar parallax.

3. How does the “thumb” test show stellar parallax?

The Birth of Modern Astronomy:The Birth of Modern Astronomy:

Johannes Kepler (1571 – 1630)Johannes Kepler (1571 – 1630)

• Used Brahe's data to enhance the three laws ofUsed Brahe's data to enhance the three laws of planetary motionplanetary motion • A mathematical mindA mathematical mind

• An emphasis on interstellar accuracy!An emphasis on interstellar accuracy!

• Proposed 3 laws of planetary motionProposed 3 laws of planetary motion• based on 10 years of mathematical computingbased on 10 years of mathematical computing• “ “Mars” did not fit the Brahe modelMars” did not fit the Brahe model

Kepler’s 1Kepler’s 1stst law of planet motion law of planet motionThe Law of EllipsesThe Law of Ellipses

• All planets follow All planets follow ellipticalelliptical orbit orbit paths (not circular paths!)paths (not circular paths!)

Kepler’s 2Kepler’s 2ndnd law of planet motion law of planet motion• The closer the planet is to the sun,The closer the planet is to the sun, the faster it “sweeps” around the faster it “sweeps” around the sun ---the sun ---

Close / fastClose / fastFar / slowFar / slow

Kepler’s 3Kepler’s 3rdrd law of planetary motion law of planetary motionTTaa

22 / T / Tbb22 = R = Raa

33 / R / Rbb33

•Square of any planet's orbital period (sidereal) is proportional to cube of its Square of any planet's orbital period (sidereal) is proportional to cube of its mean distance (semi-major axis) from Sun mean distance (semi-major axis) from Sun

•Mathematical statement: T = kRMathematical statement: T = kR3/23/2 , where T = sidereal period, and R = semi- , where T = sidereal period, and R = semi-major axis major axis

•Example - If a is measured in astronomical units (AU = semi-major axis of Example - If a is measured in astronomical units (AU = semi-major axis of Earth's orbit) and sidereal period in years (Earth's sidereal period), then the Earth's orbit) and sidereal period in years (Earth's sidereal period), then the constant k in mathematical expression for Kepler's third law is equal to 1, constant k in mathematical expression for Kepler's third law is equal to 1, and the mathematical relation becomes Tand the mathematical relation becomes T22 = R = R33

Examples of Kepler's Third Law Planet P (yr) a (AU) T2 R3

Mercury 0.24 0.39 0.06 0.06

Venus 0.62 0.72 0.39 0.37

Earth 1.00 1.00 1.00 1.00

Mars 1.88 1.52 3.53 3.51

Jupiter 11.9 5.20 142 141

Saturn 29.5 9.54 870 868

The third law says:One can calculate thedistance of a planetfrom the sun – That’sall folks!

The third law says:One can calculate thedistance of a planetfrom the sun – That’sall folks!

SUNSUN

Orbital periods - Elliptical patternsOrbital periods - Elliptical patterns

..62 y62 y

1.0 y1.0 y

1.88 y1.88 y11.86 y11.86 y

29.46 y29.46 y

The more distance – the longer the orbital periodThe more distance – the longer the orbital period

I I Johannes Kepler. Johannes Kepler.



1.Describe EACH law of planetary motion presented by Johannes Kepler.

2. How do these laws influence our knowledge and travel in our solar system?

1.Describe EACH law of planetary motion presented by Johannes Kepler.

2. How do these laws influence our knowledge and travel in our solar system?


Galileo GalileiGalileo Galilei (1564 – 1642) (1564 – 1642)• Strongly supported the heliocentric modelStrongly supported the heliocentric model• Greatest contribution to astronomy – the Greatest contribution to astronomy – the descriptions of moving objectsdescriptions of moving objects

All astronomical discoveries were made withoutAll astronomical discoveries were made withouta telescope a telescope • 1609 – constructed the first telescope1609 – constructed the first telescope• 3 times the actual size3 times the actual size• 30 times the actual size 30 times the actual size

With the telescope – Galileo made severalWith the telescope – Galileo made severaldiscoveries that supported the Copernicandiscoveries that supported the Copernicanmodel.model.

Galileo’s discoveries in a “nutshell”Galileo’s discoveries in a “nutshell”

1.1. Discovery of Jupiter's moons (4) – predicted the Discovery of Jupiter's moons (4) – predicted the periods and showed the earth is not in the centerperiods and showed the earth is not in the center

2. The planets are “spheres,” not points of light2. The planets are “spheres,” not points of light

3. Discovery of phases of Venus – and it is the 3. Discovery of phases of Venus – and it is the second planet from the sunsecond planet from the sun

4. Discovered the topography of the moon – NOT 4. Discovered the topography of the moon – NOT smooth and made of cheesesmooth and made of cheese

5. Discovered that the sun had sun-spots – leading to5. Discovered that the sun had sun-spots – leading to the calculation of the sun’s rotationthe calculation of the sun’s rotation


Sir Isaac Newton (1642 – 1727)Sir Isaac Newton (1642 – 1727)

• ““Greatest genius ever to exist in mathematics andGreatest genius ever to exist in mathematics and physics”physics”

• Realized what the gravitational force isRealized what the gravitational force is

•Keeps the planets from leaving --- and not Keeps the planets from leaving --- and not following a straight line (the tetherball conceptfollowing a straight line (the tetherball concept))

Universal Gravitational TheoryUniversal Gravitational TheoryEvery body in the universe attracts every otherEvery body in the universe attracts every other

body with a force that is directly proportional body with a force that is directly proportional to their masses and inversely proportional to to their masses and inversely proportional to

the distance between them – the distance between them –

BIGGER OBJECTS ATTRACT SMALLER OBJECTS.BIGGER OBJECTS ATTRACT SMALLER OBJECTS.

Universal Gravitation:Universal Gravitation:

• Gravity gets weaker as distance increases.Gravity gets weaker as distance increases.• Smaller objects are attracted to bigger Smaller objects are attracted to bigger objects.objects.

Big ObjectBig Object

SmallSmallobjectobject

MoonMoonBig Big objectobject

SmallSmallobjectobject

Isaac NewtonIsaac Newton

• Proved the force of gravityProved the force of gravity• Earth moves forward about 30 km/s (18.5 mi/s)Earth moves forward about 30 km/s (18.5 mi/s)• The sun pulls the earth about .5 cmThe sun pulls the earth about .5 cm

18.5 km/s18.5 km/s

.5 cm.5 cm

I I Galileo and Newton. Galileo and Newton.



1.How did Galileo contribute to our understanding of the solar system?

2. What is Newton’s contribution to our solar system --- the way we look at the solar system today?

1.How did Galileo contribute to our understanding of the solar system?

2. What is Newton’s contribution to our solar system --- the way we look at the solar system today?

23.523.5oo

As the earth orbits around the sun, insolation is directed above and below

the equator during the year.

Reasons for the Earth’s SeasonsReasons for the Earth’s Seasons

Earth’s axis is tilted atEarth’s axis is tilted at23.523.5oo

Why does the earth have seasons?Why does the earth have seasons?The most common wrong answer:

The earth gets close and far fromthe sun during its one-year revolution.

The most common wrong answer:

The earth gets close and far fromthe sun during its one-year revolution.

June 21June 21Summer solsticeSummer solstice

June 21June 21Summer solsticeSummer solstice

Sept 21Sept 21Autumn equinoxAutumn equinox

Sept 21Sept 21Autumn equinoxAutumn equinox

Dec 21Dec 21Winter solsticeWinter solstice

Dec 21Dec 21Winter solsticeWinter solstice

March 21March 21Vernal equinoxVernal equinox

March 21March 21Vernal equinoxVernal equinox Today

Today

Northern Hemisphere SeasonsNorthern Hemisphere Seasons

AprilApril

SunSun

Tropic of Capricorn

Tropic of Capricorn

Tropic of Cancer

Tropic of CancerEquator

Equator

When is the sun directly over your head?

June 21Summer solstice

June 21Summer solstice

Vernal and Autumnalequinox

March 21 / Sept 21

Vernal and Autumnalequinox

March 21 / Sept 21

Dec 21Winter solstice

Dec 21Winter solstice

Seasons in the Northern HemisphereSeasons in the Northern Hemisphere

23.5 North23.5 North

23.5 South23.5 South

0 degrees0 degrees

The view of earth from the sun’s perspectiveThe view of earth from the sun’s perspective

simulated path of the sun over 1 year simulated path of the sun over 1 year

SUN SUN

June 21(longest day)June 21(longest day)

Dec 21(shortest day)Dec 21(shortest day)

July July

AugustAugust

SeptemberSeptember

OctoberOctober

NovemberNovemberJanuaryJanuary

FebruaryFebruary

MarchMarch

AprilApril

MayMay

Bakersfield, CaliforniaBakersfield, California

Bakersfield CollegeBakersfield College

I I The seasons. The seasons.



1.Describe why the earth experiences the four seasons. Use terms such as:

tilt of earth, equinoxes, solstice, tropics of Capricorn and Cancer

1.Describe why the earth experiences the four seasons. Use terms such as:

tilt of earth, equinoxes, solstice, tropics of Capricorn and Cancer

An Overview of the PlanetsAn Overview of the Planets

1500 years of astronomicalcontributions

Know the “common differences” betweenKnow the “common differences” betweeninner and outer planetsinner and outer planets

Know the “common differences” betweenKnow the “common differences” betweeninner and outer planetsinner and outer planets

MercuryMercury

4878 km4878 km

3105 mi3105 mi

Axial tilt: Axial tilt: 0000

1 day1 day 167 days167 days

MoonsMoons 00Surface TSurface T 332 332 00CC

Named after the ancientNamed after the ancientgod of messengersgod of messengers

Atmosphere Atmosphere none none

Mercury is 36 million miles from the SUN.Mercury is 36 million miles from the SUN.

Orbital periodOrbital period 88 days88 days

VenusVenus Axial tilt: Axial tilt: 17717700

1 day1 day 116 days116 days

MoonsMoons 00

Named after the Roman Named after the Roman goddess of lovegoddess of love• All features are namedAll features are named after womenafter women• Maxwell Montes (Mt. range)Maxwell Montes (Mt. range) “ “only man on Venus”only man on Venus”

Atmosphere Atmosphere Thick CO Thick CO22

12,102 km12,102 km

7520 mi7520 mi

Venus is 67 million miles from the SUN.Venus is 67 million miles from the SUN.

Surface TempSurface Temp 867 867 00FF

Orbital PeriodOrbital Period 225 days225 days

EarthEarthAxial tilt: Axial tilt: 23.523.500

1 day1 day 1 day1 day

MoonsMoons 11

Named after Gaea (Greek)Named after Gaea (Greek)• Named for all livingNamed for all living thingsthings

Atmosphere Atmosphere O, N O, NSurface TempSurface Temp 60 60 00FF

Orbital PeriodOrbital Period 365 days365 days12,756 km12,756 km

7926 mi7926 mi

Earth is 93 million miles from the SUN.Earth is 93 million miles from the SUN.

MarsMarsAxial tilt: Axial tilt: 25.225.200

1 day1 day 24.6 hr24.6 hr

MoonsMoons 22

Named after Roman godsNamed after Roman godsof war (the red planet)of war (the red planet)

Atmosphere Atmosphere CO CO22

Surface TempSurface Temp -85 -85 00FF

Orbital PeriodOrbital Period 687 days687 days

Mars is 141 million miles from the SUN.Mars is 141 million miles from the SUN.

6794 km6794 km

4221 mi4221 mi

JupiterJupiterAxial tilt: Axial tilt: 3.133.1300

Length of dayLength of day 10 hr10 hr

MoonsMoons 6363

Named after the RomanNamed after the Romangod of lightninggod of lightning

Atmosphere Atmosphere H H22, He, HeSurface TempSurface Temp -166 -166 00FF

Orbital PeriodOrbital Period 11.9 yr11.9 yr

Jupiter is 483 million miles from the SUN.Jupiter is 483 million miles from the SUN.

142,984 km142,984 km

88,846 mi88,846 mi

SaturnSaturn

Axial tilt: Axial tilt: 26.726.700

Length of dayLength of day 10.6 hr10.6 hr

MoonsMoons 4747

Named after RomanNamed after Romanlord of the ringslord of the rings

Atmosphere Atmosphere H H22, He, HeSurface TempSurface Temp -140 -140 00FF

Orbital PeriodOrbital Period 29.5 yrs29.5 yrs

Saturn is 887 million miles from the SUN.Saturn is 887 million miles from the SUN.

120,536 km

120,536 km

74,897 mi

74,897 mi

UranusUranusAxial tilt: Axial tilt: 97.797.700

1 day1 day 17.2 hr17.2 hr

MoonsMoons 2727

Named after god (Greek)Named after god (Greek)of heavensof heavens

Atmosphere Atmosphere H H22, CH, CH44



Uranus is 1784 million miles from the SUN.Uranus is 1784 million miles from the SUN.

51,1

18 k

m51

,118

km

31,7

63 m

i31

,763

mi

NeptuneNeptuneAxial tilt: Axial tilt: 28.328.300

Length of dayLength of day 16 hrs16 hrs

MoonsMoons 1313

Named after Roman godNamed after Roman godof the seaof the sea

Atmosphere Atmosphere CH CH44, H, H22



Neptune is 2795 million miles from the SUN.Neptune is 2795 million miles from the SUN.

49,528 km49,528 km49,528 km49,528 km

30,775 mi30,775 mi30,775 mi30,775 mi

I I those planets. those planets.



1.Give at least 3 characteristics of each planet:

Mercury JupiterVenus SaturnEarth UranusMars Neptune

1.Give at least 3 characteristics of each planet:

Mercury JupiterVenus SaturnEarth UranusMars Neptune

Moon Phases and EclipsesMoon Phases and Eclipses

238,000 miles

238,000 miles

1/6 Earth’s gravity220 lb = 36 lb

3.3 g/cm3 = density

1/6 Earth’s gravity220 lb = 36 lb

3.3 g/cm3 = density

2150 miles2150 miles

12,756 miles12,756 miles

(Your weight) X (.16)(Your weight) X (.16)

The moon’s surfaceThe moon’s surfaceMariaMaria – Latin for – Latin for seasea

lowlandslowlandsbasalt flowsbasalt flows

Craters Craters – – highlands – most of the surfacehighlands – most of the surface craters within craters within craterscraters within craters within craters

Phases of the moonPhases of the moon• 7 major phases in a period of 1 month7 major phases in a period of 1 month• 1 orbital moon period = 29 days1 orbital moon period = 29 days

Fast speedFast speed - What the moon would - What the moon would look like over a month-long periodlook like over a month-long period

View from earthView from earth

Full moonFull moon

New MoonNew Moon

First QFirst Q

Last QLast Q

WaxingWaxingcrescentcrescent

WaxingWaxinggibbousgibbous

WaningWaninggibbousgibbous

Waning Waning crescentcrescent

WaxingWaxing = increasing brightness = increasing brightness

WaningWaning = decreasing brightness = decreasing brightness

Eclipses of the Moon• Lunar Eclipse• Solar Eclipse

Eclipses of the Moon• Lunar Eclipse• Solar Eclipse

Lunar EclipseLunar EclipseLunar EclipseLunar Eclipse

PenumbraPenumbra

UmbraUmbra

PenumbraPenumbraPenumbraPenumbra

Umbra

Penumbra

Penumbra

Penumbra

UmbraUmbraUmbraUmbra

Penumbra

Penumbra

Penumbra

Penumbra

Penumbra

Penumbra

Total Eclipse of the SunTotal Eclipse of the Sun

Partial eclipse – the view outsidethe penumbra

Partial eclipse – the view outsidethe penumbra

Spectators pay BIG money to be in the umbra.Spectators pay BIG money to be in the umbra.

SUN – EARTH---MOON SUN – MOON – EARTHSUN – MOON – EARTH

Sun Sun

Lunar EclipseLunar Eclipse Solar EclipseSolar Eclipse

I I the nebular hypothesis. the nebular hypothesis.



1.Draw a diagram that shows the various phases of the moon – use the vocabulary (waxing / waning).

2. Draw a diagram depicting the differences between a lunar and a solar eclipse.

1.Draw a diagram that shows the various phases of the moon – use the vocabulary (waxing / waning).

2. Draw a diagram depicting the differences between a lunar and a solar eclipse.

Minor members of the solar systemMinor members of the solar system

Asteroid - Asteroid - small rocky bodies that are irregularsmall rocky bodies that are irregular in shape – 10,000 or more lie betweenin shape – 10,000 or more lie between Jupiter and Mars (the asteroid belt)Jupiter and Mars (the asteroid belt)

Proposed asteroid impact on EarthProposed asteroid impact on Earth

250,000 mile

s

250,000 mile

s

Aster

oid

dire

ctio

n

Aster

oid

dire

ctio

n

Aster

oid

dire

ctio

n

Asteroid direction

March 21, 2014April 13, 2029 - Friday

Minor members of the solar systemMinor members of the solar system

CometComet: - : - A large “ice-ball” composed of dustA large “ice-ball” composed of dust and space debris which enters the solar and space debris which enters the solar system from an outside source system from an outside source

CometComet

Head Head (coma)(coma)

Tail (Tail (dust left over)dust left over)

Hypothesized to originate from a distant Ort cloudHypothesized to originate from a distant Ort cloud

How a comet orbits our sun – enters from the ortHow a comet orbits our sun – enters from the ortcloudcloud

Halley’s Comet• 1986 was its last appearance• appears every 76 years• next appearance -- 2062

Halley’s Comet• 1986 was its last appearance• appears every 76 years• next appearance -- 2062

What year should a person have been born to seeHalley’s comet twice in their lifetime?

What year should a person have been born to seeHalley’s comet twice in their lifetime?

Halley’s CometHalley’s Comet

Astronomy VocabularyAstronomy Vocabulary

MeteorMeteor – – small to boulder-size rock particle thatsmall to boulder-size rock particle that enters the earth’s atmosphere – air enters the earth’s atmosphere – air friction causes the rock to “burn” friction causes the rock to “burn” creating a “falling-star”creating a “falling-star”

Meteor shower Meteor shower

I I comets, asteroids, andmeteorites. comets, asteroids, andmeteorites.



1.Describe the differences between an asteroid, meteorite, and comet. 1.Describe the differences between an asteroid, meteorite, and comet.

the nature of our solar system the nature of our solar system

Documents

geocentric retrograde

heliocentric retrograde

adthe solar system

heliocentric model stars

solar system mass

centered earth

rotating earth

laws of planetary motion