Physical Science

Physical SciencePhysical Science

Solar SystemSolar System

Slides subject to changeSlides subject to change

Psalm 19Psalm 19

11 The heavens declare the glory of God; The heavens declare the glory of God;

the skies proclaim the work of his hands.the skies proclaim the work of his hands.22 Day after day they pour forth speech; Day after day they pour forth speech;

night after night they display knowledge.night after night they display knowledge.

Geocentric ModelGeocentric Model

PtolemyPtolemy ca 140 A.D.ca 140 A.D. Egyptian astronomer.Egyptian astronomer. GeocentricGeocentric system (Earth-centered). system (Earth-centered). Stars and planets are embedded in Stars and planets are embedded in

rotating spheres, with Earth at the center.rotating spheres, with Earth at the center. Spheres made of an aetherial Spheres made of an aetherial

transparent fifth element (quintessence). transparent fifth element (quintessence). Like jewels set in orbs.Like jewels set in orbs.

Medieval chemistry – four elements earth, air, Medieval chemistry – four elements earth, air, fire, and water.fire, and water.

Earth surrounded by “rotating” spheres.Earth surrounded by “rotating” spheres.

Outer sphere beyond the stars is unmovingOuter sphere beyond the stars is unmoving——where God dwells.where God dwells.

Geocentric ConclusionsGeocentric Conclusions

Some Biblical ArgumentsSome Biblical Arguments

Psalm 93:1 “... The world is firmly Psalm 93:1 “... The world is firmly established; it cannot be moved.”established; it cannot be moved.”

Psalm 104:5 “He set the earth on its Psalm 104:5 “He set the earth on its foundations; it can never be moved.foundations; it can never be moved.

Why don’t these work?Why don’t these work?

Heliocentric ModelHeliocentric Model Nicolaus Copernicus, Nicolaus Copernicus, Polish Polish

astronomer.astronomer.

Proposes Proposes heliocentricheliocentric system, system, Orbits of planets are perfect circles, Orbits of planets are perfect circles,

with the with the SunSun at the center. at the center. Fears criticism, and sees first printed Fears criticism, and sees first printed

edition of his work as he dies in edition of his work as he dies in 1543.1543.

Heliocentric − “Sun” in the CenterHeliocentric − “Sun” in the Center

Scientific MethodScientific Method

1.1. ObserveObserve some aspect of the universe. some aspect of the universe.

2.2. InventInvent a tentative description, called a a tentative description, called a hypothesishypothesis, consistent with what you have , consistent with what you have observed.observed.

3.3. UseUse the hypothesis to make predictions. the hypothesis to make predictions.

4.4. TestTest those predictions and modify the hypothesis those predictions and modify the hypothesis in the light of your results.in the light of your results.

5.5. RepeatRepeat steps 3 and 4 until there are no steps 3 and 4 until there are no discrepancies between theory and experiment discrepancies between theory and experiment and/or observation.and/or observation.

Need Accurate DataNeed Accurate Data Tycho BraheTycho Brahe 1546 – 16011546 – 1601

Significant work aboutSignificant work about 1600 A.D. 1600 A.D. Danish nobleman.Danish nobleman. Most accurate astronomical measurements Most accurate astronomical measurements

of his time.of his time. No telescope.No telescope. Unusual geocentric model, “the Earth is just Unusual geocentric model, “the Earth is just

too sluggish to be continually in motion.”too sluggish to be continually in motion.”

Need Accurate DataNeed Accurate Data Johannes KeplerJohannes Kepler 1571 – 1630 1571 – 1630

Significant work Significant work 1605 A.D.1605 A.D. German mathematician, assists Tycho German mathematician, assists Tycho

Brahe.Brahe. Believes heliocentric solar system, Believes heliocentric solar system,

and tries to convince Tycho.and tries to convince Tycho. Finds the orbits are mathematical Finds the orbits are mathematical

ellipsesellipses.. Three laws of planetary motion.Three laws of planetary motion.

Kepler’s Orbit ModelKepler’s Orbit Model

Other FiguresOther Figures

Galileo Galilei Galileo Galilei 1564 – 16421564 – 1642

Significant work Significant work 1632 A.D.1632 A.D. Italian physicist.Italian physicist. Observed sky with telescope.Observed sky with telescope. Moon has craters, Jupiter has Moon has craters, Jupiter has

moons, Venus has phases.moons, Venus has phases. Champions Copernicus.Champions Copernicus. He’s in Big trouble with Pope.He’s in Big trouble with Pope.

Other FiguresOther Figures Isaac NewtonIsaac Newton 1642 – 17271642 – 1727

Significant work 1667 A.D.Significant work 1667 A.D. English mathematician, English mathematician,

physicist.physicist. Degree from Cambridge in Degree from Cambridge in

1665, university closes due 1665, university closes due to Plague, he goes home.to Plague, he goes home.

Proposes celestial and terrestrial physics are related (Proposes celestial and terrestrial physics are related (apple incidentapple incident). ). Law of gravity, attraction between masses.Law of gravity, attraction between masses.

1.1. All planets move in elliptical orbits around the All planets move in elliptical orbits around the Sun, with the Sun at one focus of the ellipse.Sun, with the Sun at one focus of the ellipse.

2.2. An imaginary line joining a planet to the Sun An imaginary line joining a planet to the Sun sweeps out sweeps out equal areasequal areas in in equal timeequal time. .

Animation: Animation: Beige areas have equal areas.Beige areas have equal areas.http://www.astrobio.nau.edu/~koerner/ast180/lectures/pic/cdrom/animations/movie-02-04.swfhttp://www.astrobio.nau.edu/~koerner/ast180/lectures/pic/cdrom/animations/movie-02-04.swf

3.3. (period)(period)22 = k (semi-major axis) = k (semi-major axis)33

Kepler’ Three LawsKepler’ Three Laws

Example of Kepler’s 3Example of Kepler’s 3rdrd Law Law

Let Let T T = period, and = period, and RR = semi-major axis = semi-major axis

= = kk

For For Mars, Mars, find orbital period find orbital period TT : :

k = = k = =

TT22 = (1) = (1)22 x = 3.51 x = 3.51

T = sqrt (3.51) =1.87 “Earth” yearsT = sqrt (3.51) =1.87 “Earth” years

((TTEarthEarth))22

((RREarthEarth))33

(1 year)(1 year)2 2

(1.00 AU)(1.00 AU)33

TT22

(1.52 AU)(1.52 AU)33

(1.52 AU)(1.52 AU)3 3

(1.00 AU)(1.00 AU)33

EarthEarth MarsMars

Images from Images from Michael Richmond, RIT

Lima, PeruLima, PeruRochester, NYRochester, NY

Parallax from different locationsParallax from different locations

TrigonometryTrigonometry

MarsMars

Measuring Distances Using Measuring Distances Using ParallaxParallax

Nine PlanetsNine Planets

MercuryMercury VenusVenus EarthEarth MarsMars JupiterJupiter SaturnSaturn UranusUranus NeptuneNeptune PlutoPluto

Pluto’s too tiny.Pluto’s too tiny.

Inner PlanetsInner Planets

Mercury Venus Earth MarsMercury Venus Earth Mars

Size to ScaleSize to Scale

#3 Earth#3 Earth Diameter: 7,900 mi or 12,740 km.Diameter: 7,900 mi or 12,740 km. Mass: 6.0x10Mass: 6.0x102424 kg kg Density: 5.52 g/cmDensity: 5.52 g/cm33.. Acceleration due to gravity: 1 Acceleration due to gravity: 1 g g or 9.8 or 9.8

m/sm/s22 or 32 ft/s or 32 ft/s22.. Temp: -88Temp: -88°C°C →→ 58 58°C°C

Orbital radius (mean) 93x10Orbital radius (mean) 93x1066 miles, miles, 150x10150x1066 km, or km, or 1 AU1 AU

Earth Year: 365.25 daysEarth Year: 365.25 days Earth Day: 24 hoursEarth Day: 24 hours

MoonMoon

Diameter: 0.27 Earths (~1/4 Earth diameter)Diameter: 0.27 Earths (~1/4 Earth diameter) Mass: 1.2% EarthMass: 1.2% Earth Density: 3.35 g/cmDensity: 3.35 g/cm3 3

Gravity: 0.16 g (~1/6 Earth gravity)Gravity: 0.16 g (~1/6 Earth gravity)

Orbital radius (mean) 384,000 kmOrbital radius (mean) 384,000 km Lunar Earth Orbit: 27.3 daysLunar Earth Orbit: 27.3 days Lunar Day: 27.3 days Lunar Day: 27.3 days (same (same

side always faces Earth)side always faces Earth)

Earth’s AtmosphereEarth’s Atmosphere

Gas NameGas Name Chemical Chemical SymbolSymbol

Percent %Percent %

NitrogenNitrogen NN22 78.0878.08

OxygenOxygen OO22 20.9520.95

ArgonArgon AA 0.930.93

Carbon DioxideCarbon Dioxide COCO22 0.040.04

Water vapor about 1 - 4% near surfaceWater vapor about 1 - 4% near surface

Axial Tilt 23.5Axial Tilt 23.5°° . .

Precession: 26,000 y period.Precession: 26,000 y period.

EclipticEcliptic Earth reaches its closest distance to Sun in Earth reaches its closest distance to Sun in

January.January. The Earth travels to its farthest point from the The Earth travels to its farthest point from the

Sun in July.Sun in July.

Other PlanetsOther Planets

Relative SizesRelative Sizes

Compare the Sun to the size of a 26-inch Compare the Sun to the size of a 26-inch diameter exercise ball:diameter exercise ball:

Earth ¼ inch in diameter (pea-size), about Earth ¼ inch in diameter (pea-size), about 230 feet away (in the student parking lot).230 feet away (in the student parking lot).

Pluto about 2 miles away (at Irwindale Pluto about 2 miles away (at Irwindale Costco). Costco). see demosee demo

#1 Mercury#1 Mercury

Diameter: 0.383 EarthsDiameter: 0.383 Earths Mass: 8.5% EarthMass: 8.5% Earth Density: 5.43 g/cmDensity: 5.43 g/cm33

Gravity: 0.38 gGravity: 0.38 g Equator Temp: Equator Temp: ––170 170 → → 430 430 °C (hot enough to °C (hot enough to

melt lead)melt lead)

Orbital radius (mean) 0.387 AUOrbital radius (mean) 0.387 AU Mercurian Year: 88 daysMercurian Year: 88 days Mercurian Day: 58 daysMercurian Day: 58 days

Closest to Closest to Sun, hotSun, hot

#2 Venus#2 Venus

Diameter: 0.950 EarthsDiameter: 0.950 Earths Mass: 0.815 EarthMass: 0.815 Earth Density: 5.20 g/cmDensity: 5.20 g/cm33

Gravity: 0.90 gGravity: 0.90 g Mean Temp: 460 Mean Temp: 460 °C (also hot enough to melt °C (also hot enough to melt

lead), evenly distributed.lead), evenly distributed.

Orbital radius (mean) 0.723 AUOrbital radius (mean) 0.723 AU Venusian Year: 225 daysVenusian Year: 225 days Venusian Day: 243 days (slow)Venusian Day: 243 days (slow)

AtmosphereAtmosphere: : Carbon dioxide, some sulfuric acidCarbon dioxide, some sulfuric acid

Enshrouded Enshrouded in cloudsin clouds

Venus Venus 9/9/139/9/13

MoonMoon

#4 Mars#4 Mars

Diameter: 0.533 EarthsDiameter: 0.533 Earths Mass: 0.107 EarthMass: 0.107 Earth Density: 3.93 g/cmDensity: 3.93 g/cm33

Gravity: 0.38 gGravity: 0.38 g Temp: Temp: ––107 107 °C°C → → ––17 17 °C °C

COCO22 freezes into dry ice. freezes into dry ice.

Orbital radius (mean) 1.52 AUOrbital radius (mean) 1.52 AU Martian Year: 687 daysMartian Year: 687 days Martian Day: 24.6 hoursMartian Day: 24.6 hours

SurfaceSurface, Mars Viking, Mars Viking

AtmosphereAtmosphere: 95% : 95% Carbon dioxide, 2.7% NCarbon dioxide, 2.7% N22

Red planetRed planet

Mars ExplorationMars Exploration

Mars Science LaboratoryMars Science Laboratory Nicknamed “Curiosity”Nicknamed “Curiosity” Launched November 26, 2011 Launched November 26, 2011 Successfully landed in Gale Crater on Successfully landed in Gale Crater on

August 6, 2012.August 6, 2012.

Mars Springtime in 2020Mars Springtime in 2020

Outer “Jovian” PlanetsOuter “Jovian” Planets

#5 Jupiter#5 Jupiter

Diameter: 10.8 EarthsDiameter: 10.8 Earths Mass: 318 EarthsMass: 318 Earths Density: 1.33 g/cmDensity: 1.33 g/cm33

Gravity: 2.53 gGravity: 2.53 g Temp: Cloud top Temp: Cloud top ––145 145 °C, hot °C, hot

interiorinterior

Orbital radius (mean) 5.20 AUOrbital radius (mean) 5.20 AU Jovian Year: 11.9 Earth YearsJovian Year: 11.9 Earth Years Jovian Day: 9.9 hoursJovian Day: 9.9 hours

Mostly hydrogen and heliumMostly hydrogen and helium

Gas giantGas giant

Galilean MoonsGalilean Moons

Io, Europa, Ganymede and Callisto.Io, Europa, Ganymede and Callisto.

Jupiter, Io, and Shadow, Jupiter, Io, and Shadow, CassiniCassini

#6 Saturn#6 Saturn

SaturnSaturn, from Voyager, from Voyager

Diameter: 9.0 EarthsDiameter: 9.0 Earths Mass: 95 EarthsMass: 95 Earths Density: 0.69 g/cmDensity: 0.69 g/cm33 (less than water)(less than water)

Gravity: 0.91 gGravity: 0.91 g Temp: Cloud top Temp: Cloud top ––150 150 °C, hot interior°C, hot interior

Orbital radius (mean) 9.58 AUOrbital radius (mean) 9.58 AU Saturnian Year: 29.7 Earth YearsSaturnian Year: 29.7 Earth Years Saturnian Day: 10.6 hoursSaturnian Day: 10.6 hours Saturn RingsSaturn Rings, from Cassini, from Cassini

Mostly hydrogen, helium, some Mostly hydrogen, helium, some sulfursulfur

Stunning ringsStunning rings

Saturn, from Hubble Space Telescope

#7 Uranus#7 Uranus Discovered 1781, first planet Discovered 1781, first planet

discovered with a telescope.discovered with a telescope. Diameter: 4.0 EarthsDiameter: 4.0 Earths Mass: 14.5 EarthsMass: 14.5 Earths Density: 1.27 g/cmDensity: 1.27 g/cm33

Gravity: 0.89 gGravity: 0.89 g Temp: Cloud top Temp: Cloud top ––220 220 °C, cold interior°C, cold interior

Orbital radius (mean) 19.2 AUOrbital radius (mean) 19.2 AU Uranian Year: 84.3 Earth YearsUranian Year: 84.3 Earth Years Uranian Day: 17.2 hoursUranian Day: 17.2 hours

UranusUranus, from Voyager 2, from Voyager 2

Blue-green Blue-green and tiltedand tilted

UranusUranus, from Hubble, from Hubble

Mostly hydrogen, helium, Mostly hydrogen, helium, some methanesome methane

UranusUranus

Spins on axis tilted 98Spins on axis tilted 98° from ° from perpendicular.perpendicular.

Discovered 1846, influences Uranus orbit.Discovered 1846, influences Uranus orbit. Diameter: 3.8 EarthsDiameter: 3.8 Earths Mass: 17 EarthsMass: 17 Earths Density: 1.64 g/cmDensity: 1.64 g/cm33

Gravity: 0.91 gGravity: 0.91 g Temp: Cloud top Temp: Cloud top ––200 200 °C, hot interior°C, hot interior

Orbital radius (mean) 30.1 AUOrbital radius (mean) 30.1 AU Neptunian Year: 165 Earth YearsNeptunian Year: 165 Earth Years Neptunian Day: 16.1 hoursNeptunian Day: 16.1 hours

#8 Neptune#8 Neptune

Mostly hydrogen, helium, some Mostly hydrogen, helium, some methanemethane

Blue planetBlue planet

Virtually no Virtually no atmosphereatmosphere

Pluto (now, a Dwarf Planet)Pluto (now, a Dwarf Planet) Discovered 1930, due to suspected Discovered 1930, due to suspected

influence on orbits of Uranus and influence on orbits of Uranus and Neptune, by Clyde Tombaugh, Lowell Neptune, by Clyde Tombaugh, Lowell Observatory, Flagstaff, AZ.Observatory, Flagstaff, AZ.

Diameter: 0.2 Earths (smaller than the Diameter: 0.2 Earths (smaller than the Moon) Moon)

Mass: 0.0021 EarthsMass: 0.0021 Earths Density: 2.0 g/cmDensity: 2.0 g/cm33, rock and ice., rock and ice. Gravity: 0.06 gGravity: 0.06 g Temp: Temp: ––230 230 °C°C

Artist ConceptArtist Concept

Orbital radius (mean) 39.5 AU.Orbital radius (mean) 39.5 AU. Plutonian Year: 248 Earth Years.Plutonian Year: 248 Earth Years. Plutonian Day: 9.4 hours.Plutonian Day: 9.4 hours.

Pluto ImagesPluto Images

Motion observed by Clyde TombaughMotion observed by Clyde Tombaugh

New Horizons SpacecraftNew Horizons Spacecraft Velocity approximately 16,000 mi/hr (4.4 Velocity approximately 16,000 mi/hr (4.4

mi/s). Launched January 2006.mi/s). Launched January 2006. Encounter July 2015. Encounter July 2015. Location TodayLocation Today..

As it approaches Pluto, will take about 9 As it approaches Pluto, will take about 9 hours for round trip radio communicationshours for round trip radio communications——EEarth to Pluto/New Horizons.arth to Pluto/New Horizons.

Charon

Sun