Astronomy 101The Solar SystemTuesday, Wednesday, ThursdayTom [email protected] 101The Solar SystemTuesday, Wednesday, ThursdayTom [email protected] Planets•Have different surface properties– Due to size of the planet–Distance from Sun–Distance from Sun–Speed of Planetary RotationTerrestrial PlanetsHave different surface propertiesSpeed of Planetary RotationGoldilocks Principle•The Goldilocks Principle can be summed up neatly as "Venus is too hot, Mars is too cold, and Earth is just right.”Goldilocks PrincipleThe Goldilocks Principle can be summed up neatly as "Venus is too hot, Mars is too cold, and Earth is just right.”http://college.cengage.com/geology/resources/protected/physicallab/thelab/interior/index.htmcollege.cengage.com/geology/resources/protected/physicallab/thelab/interior/index.htmEarth’s InteriorEarth’s InteriorEarth’s crust• 46.6% O• 27.7% Si• 8.1% Al •5.0% Fe •5.0% Fe • 3.6% Ca• 2.8% Na• 2.6% K • 2.1% Mg Earth’s crustEarth is made of mineralsEarth is made of mineralsMineral•A naturally occurring, homogeneous inorganic solid substance having a definite chemical composition and characteristic crystal structurecomposition and characteristic crystal structureMineralA naturally occurring, homogeneous inorganic solid substance having a definite chemical composition and characteristic crystal structurecomposition and characteristic crystal structureOlivine• (Mg, Fe)2SiO4• Fayalite (Fa) - Fe2SiO4• Forsterite (Fo) - Mg2SiOOlivineSiO4Pyroxenes• XY(Si, Al)2O6• X can be Ca, Na, Fe+2, Mg, Zn, Mn, and Li• Y can be Cr, Al, Fe+3, Mg, Mn, Sc, Ti, V, and FeAugite FerrosilitePyroxenes, Mg, Zn, Mn, and Li, Mg, Mn, Sc, Ti, V, and Fe+2FerrosiliteHow do we know what’s in the interior of the Earth?How do we know what’s in the interior of the Earth?How do we know what’s in the interior of the Earth?• Seismic Waves –vibrations created by earthquakesHow do we know what’s in the interior of the Earth?vibrations created bySeismic Waves• P waves – primary waves – (pushing) – travel faster – can travel through anythinganything• S waves – secondary –(side to side) – travel slower – only through solidsSeismic Waves•http://alomax.free.fr/alss/examples/hodo/hodo_example.htmlhttp://alomax.free.fr/alss/examples/hodo/hodo_exSurface Waves•Travel on the surface of the Earth• Love Wave –side by side•http://www.geo.mtu.edu/UPSeis/images/Love_animation.gif• Rayleigh Wave –rolling movement•http://www.geo.mtu.edu/UPSeis/images/Rayleigh_animation.gif•Most of the shaking felt from an earthquake is due to the Rayleigh wavesSurface WavesTravel on the surface of the Earthside by sidehttp://www.geo.mtu.edu/UPSeis/images/Love_anirolling movementhttp://www.geo.mtu.edu/UPSeis/images/RayleighMost of the shaking felt from an earthquake is dueP (primary) wavesS (secondary) wavesSurface waves: Rayleigh and Love wavesP (primary) wavesS (secondary) wavesSurface waves: Rayleigh and Love wavesRichter Scale•Measures the magnitude of an earthquake•Single number to quantify the amby an earthquake. Amplitude of largest displacement•Under 6.0 -At most slight damage to well•Under 6.0 -At most slight damage to wellCan cause major damage to poorly constructed buildings.• 6.1-6.9 -Can be destructive in across where people live.• 7.0-7.9 -Major earthquake. Can cause serious damage over larger areas.• 8 or greater -Great earthquake. Can cause serious damage in areas several hundred kilometers across.Richter ScaleMeasures the magnitude of an earthquake the amount of seismic energy released by an earthquake. Amplitude of largest displacementAt most slight damage to well-designed buildings. At most slight damage to well-designed buildings. Can cause major damage to poorly constructed buildings.ive in areas up to about 100 kilometers Major earthquake. Can cause serious damage over Great earthquake. Can cause serious damage in areas several hundred kilometers across.How do we get information?•The precise speed and direction of the waves depends on the composition, density, pressure, temperature, and phase (solid or liquid)temperature, and phase (solid or liquid)How do we get information?The precise speed and direction of the waves depends on the composition, density, pressure, temperature, and phase (solid or liquid)temperature, and phase (solid or liquid)Which of these bodies have they used seismic waves to study?Which of these bodies have they used seismic waves to study?How can you study the interior of a planet?How can you study the interior of a planet?Density• Density = mass/volume•If the density is higher than the surface rock, there must be denser material in the interiormust be denser material in the interiorDensityIf the density is higher than the surface rock, there must be denser material in the interiormust be denser material in the interiorρ= Mass/VolumeρEarth= 5.515 g/cmMetallic ironMetallic ironBasaltWaterCold ices and hydrogen= Mass/Volume= 5.515 g/cm3Density (g/cm3)7.877.873.31.00.07-0.09Density (g/cm3)Iron 7.87Basalt3.3What do these densities tell us?Basalt3.3Water 1.0Cold ices 0.07-0.09DensityGravity•If you can measure the gravity (force) on a spacecraft as it rotates around a body, you can determine how mass is distributed on the bodydetermine how mass is distributed on the bodyGravityIf you can measure the gravity (force) on a spacecraft as it rotates around a body, you can determine how mass is distributed on the bodydetermine how mass is distributed on the bodyMagnetic Field•Tells if a planet has a molten metal interiorMagnetic FieldTells if a planet has a molten metal interiorhttp://www.gcsescience.com/pme1.htmhttp://www.gcsescience.com/pme1.htmEarth’s magnetic field is believed to be caused by the convection of molten iron, within the outer liquidrotation of the planet http://geomag.usgs.gov/images/faq/Q6.jpgElectrons flowEarth’s magnetic field is believed to be caused by the convection of molten iron, liquid core along with the rotation of the planet http://geomag.usgs.gov/images/faq/Q6.jpghttp://www.scifun.ed.ac.uk/card/images/left/earthhttp://www.scifun.ed.ac.uk/card/images/left/earth-magfield.jpg• Magnetic pole
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