NeptuneNeptuneandand

TritonTriton

Bit of Administration ….Bit of Administration ….• ReadingReading

– BSNV Chap. 12BSNV Chap. 12

• Homework 9Homework 9– Due Friday, April 23, in box by Mathieu office door (6522) SterlingDue Friday, April 23, in box by Mathieu office door (6522) Sterling

• Change in Portfolio Points and Course Grade ScaleChange in Portfolio Points and Course Grade Scale– Portfolio is worth Portfolio is worth 50 pts 50 pts instead of 70instead of 70

– Same as 6- and 12-week examsSame as 6- and 12-week exams

– Course grade scale will be same percentagesCourse grade scale will be same percentages– A 342/380A 342/380– AB 332AB 332– B 285B 285– BC 275BC 275– C 228C 228– D 190D 190

Planetary EvolutionPlanetary Evolution

• Comparative Planetology - EarthComparative Planetology - Earth

Plate tectonics is critical to Earth atmospherePlate tectonics is critical to Earth atmosphere

washed out with H20 rain

Ozone O3

Planetary EvolutionPlanetary Evolution• Comparative Planetology - Mars at 1 billion yrComparative Planetology - Mars at 1 billion yr (end of geologic activity)(end of geologic activity)

1.1. HH22O rain washes COO rain washes CO22 into surface - into surface - permanentlypermanently

2.2. Greenhouse effect reducedGreenhouse effect reduced3.3. Colder temperatures lead to enhanced rain, less gaseous COColder temperatures lead to enhanced rain, less gaseous CO22, less greenhouse, less greenhouse

(“Runaway Icehouse Effect”)(“Runaway Icehouse Effect”)4.4. Most COMost CO22 in carbonate rocks, most H in carbonate rocks, most H22O in permafrostO in permafrost

5.5. UV sunlight breaks up molecules and provides energy of escapeUV sunlight breaks up molecules and provides energy of escape

UV

O,C

Planetary EvolutionPlanetary Evolution

• Comparative Planetology - Earth and VenusComparative Planetology - Earth and Venus

VenusVenus EarthEarth

Active volcanos Active volcanosActive volcanos Active volcanos

Planetary EvolutionPlanetary Evolution

• Comparative Planetology - Earth and VenusComparative Planetology - Earth and Venus

VenusVenus EarthEarth

Active volcanos Active volcanosActive volcanos Active volcanosVVescesc = 10.3 km/sec V = 10.3 km/sec Vescesc = 11.2 km/sec = 11.2 km/sec

COCO22 atmosphere atmosphere N N22/O/O22 atmosphere atmosphere

(90 atmos) (1 atmos)(90 atmos) (1 atmos)Dry (10Dry (10-4-4 Earth H Earth H220) Water at present0) Water at present

Note: Based on measurements of deuterium (“heavy water”)Note: Based on measurements of deuterium (“heavy water”) Venus had substantially more water in the pastVenus had substantially more water in the past Consistent with outgassing from volcanos and largeConsistent with outgassing from volcanos and large escape velocityescape velocity

Planetary AtmospheresPlanetary Atmospheres

• Comparative Planetology - VenusComparative Planetology - Venus• Suppose Venus were “Earth-like” (liquid water) and …Suppose Venus were “Earth-like” (liquid water) and …

Light from Sun Light from Sun or COor CO22, H, H22O O

Temperature Temperature

COCO22, H, H22O O

from oceansfrom oceansfrom rocksfrom rocks

““Runaway Greenhouse Effect”Runaway Greenhouse Effect”

Planetary AtmospheresPlanetary Atmospheres

• Runaway Greenhouse EffectRunaway Greenhouse Effect

• once RGE begins …once RGE begins …

RGERGEHH220 in0 in

atmosatmos

UVUVfromfromSunSun

HH22

OO22

EscapeEscape

SurfaceSurfaceCompoundsCompounds

++

Irreversible!!Irreversible!!

Planetary AtmospheresPlanetary Atmospheres

• Comparative Planetology - Venus at 4.5 billion yrComparative Planetology - Venus at 4.5 billion yr

Dry (10Dry (10-4-4 Earth H Earth H220)0)

Planetary Evolution - SummaryPlanetary Evolution - Summary

MercuryMercury

Trace ofTrace ofHe, Na, OHe, Na, O

VenusVenus

96% CO96% CO22

470 470 ooCC90 atmospheres90 atmospheres

EarthEarth

77% N77% N22, 21% O, 21% O22

15 15 ooCC1 atmosphere1 atmosphere

Moon Trace of He, Na, ArMoon Trace of He, Na, Ar

MarsMars

95% CO95% CO22

-50 -50 ooCC0.01 atmospheres0.01 atmospheres

Planetary Evolution - SummaryPlanetary Evolution - Summary

• Geological EvolutionGeological Evolution• Mercury, Moon - smallest radii => dormant, crateredMercury, Moon - smallest radii => dormant, cratered• Mars - active for 10Mars - active for 1099 yr, now dormant (shield volcanoes) yr, now dormant (shield volcanoes)• Venus - current volcanos (shield volcanoes)Venus - current volcanos (shield volcanoes)• Earth - convection => plate tectonicsEarth - convection => plate tectonics

• Atmospheric EvolutionAtmospheric Evolution• Moon, Mercury - low escape velocity, hot, atmos escapesMoon, Mercury - low escape velocity, hot, atmos escapes• Venus RGE, massive COVenus RGE, massive CO22 atmos atmos• Earth COEarth CO22, H, H22O , NO , N22 N N22, O, O22

• Mars Runaway Icehouse,Mars Runaway Icehouse, thin COthin CO22 atmos atmos

Jovian PlanetsJovian Planets

Jovian PlanetsJovian Planets

2.5 x rest of Solar System (excepting Sun)2.5 x rest of Solar System (excepting Sun)

(Methane, Ammoniaat surface)

Methane CH4, Ammonia NH3

(Methane, Ammoniaat surface)

Jovian PlanetsJovian Planets

• RotationRotation• Jupiter - 9 hours, 55 minutes at equatorJupiter - 9 hours, 55 minutes at equator• Saturn - 10 hours, 20 minutesSaturn - 10 hours, 20 minutes

QuickTime™ and aMicrosoft Video 1 decompressorare needed to see this picture. DifferentialDifferentialRotationRotation

Jovian PlanetsJovian Planets

• RotationRotation• Jupiter - 9 hours, 55 minutes at equatorJupiter - 9 hours, 55 minutes at equator• Saturn - 10 hours, 20 minutesSaturn - 10 hours, 20 minutes

• Oblateness and Internal StructureOblateness and Internal Structure

• Jupiter - 4% in solid core (13 x Earth mass)Jupiter - 4% in solid core (13 x Earth mass)• Saturn - 26% in solid coreSaturn - 26% in solid core

Jovian PlanetsJovian Planets

•Oblateness and Internal Structure - JupiterOblateness and Internal Structure - Jupiter

Jovian PlanetsJovian Planets

•Jovian WeatherJovian Weather

Jovian PlanetsJovian Planets

•Jovian WeatherJovian Weather

QuickTime™ and aYUV420 codec decompressorare needed to see this picture.

Jovian PlanetsJovian Planets•Jovian WeatherJovian Weather

Jupiter emits 2x the energy it receives from the Sun!Jupiter emits 2x the energy it receives from the Sun!

Infrared VisibleInfrared Visible

Jovian PlanetsJovian Planets

•Jovian WeatherJovian Weather

ConvectionConvection