Presentation on theme: "Warm Up Which inner planet is the hottest?"— Presentation transcript:
1Warm Up 3-2-15 Which inner planet is the hottest? What’s so special about Mars?What is the purpose of spending billions of dollars to explore outer space?Agenda-Turn in homework-Notes Chp 27-3-Outer Planets video-Test Review WorksheetHomeworkTest Chp 26/27
4Space Craft Exploration of Jovian Planets Voyager 1 and 2 left Earth in 1977 and reached Jupiter in March and July of 1979Used Jupiter’s strong gravity to send them on to Saturn - gravity assistVoyager 2 used Saturn’s gravity to propel it to Uranus and then on to NeptuneStudied planetary magnetic fields and analyzed multi-wavelength radiationBoth are now headed out into interstellar spaceGalileo - launched in 1989 and reached Jupiter in December 1995Two components: atmospheric probe and orbiterProbe descended into Jupiter’s atmosphere and orbiter went through moon systemCassini mission to Saturn arrived June 30, 2004orbiter continues to orbit Saturn and its moonsHuygens probe launched from the orbiter January 14, 2005 to study Saturn’s moon Titan.Background information Voyager is on going for 37 years
5Jovian Planet Properties Most of their mass is Hydrogen and Helium – light elements = low densitiesHigh surface gravity allows their atmospheres to retain these light elementsDense compact core at the center - no solid surface – gaseous atmosphere becomes denser (eventually liquid) at coreDifferential Rotation – outer regions rotate at a different rate than the inner regions
6Jovian Planet Properties All Jovian planets have strong magnetic fields - rapid rotation and liquid conductive cores or mantlesUranus has the most inclined rotational axis (extreme seasons)
7Jupiter’s Atmosphere helium – 14% molecular hydrogen – 86%helium – 14%small amounts of methane, ammonia, and water vaporDarker belts lie atop downward moving convective cells Lighter zones are above upward moving cells. Belts are low-pressure, zones are high pressureAsJupiter’s rotation causes wind patterns to move East/West along equatorTemperature difference between bands is main reason for color difference
8Weather on Jupiter Main weather feature – Great Red Spot! swirling hurricane windshas lasted over 300 yearsdiameter twice that of Earthrotates with planet’s interiorthe spot appears to be confined and powered by the zonal flowsmaller storms look like white ovalsDiscovered 7th or 8th century BC by the Babylonians (present day Iraq)
9Saturn’s Atmosphere hydrogen 92.4% helium 7.4% traces of methane and ammoniaOverall temperature is cooler than JupiterThicker clouds result in less varied visible colors
10Saturn’s AtmosphereCloud layer thickness is 3 times that of Jupiter (caused by lower surface gravity on Saturn)9 main rings composed of dust and ice particles extend 6 million miles above the surface62 known moons orbiting the planetstorm systems, and turbulent flow patternsCloud layer thickness is 3 times that of Jupiter (caused by lower surface gravity on Saturn) with winds reaching 600mi/hr-Rings hypothesis made from nebula or destroyed moons with titans being the largest
11Atmospheres of Uranus and Neptune Hydrogen 84%Helium 14%Methane 2% (Uranus) 3% (Neptune)Abundance of methane gives these planets their blue color.Methane absorbs longer wavelength light (red) and reflects short wavelength light (blue)
12Atmospheres of Uranus and Neptune Few clouds in the cold upper atmosphere – featurelessUpper layer of haze blocks out the lower, warmer cloudsNeptuneUpper atmosphere is slightly warmer than Uranus (despite its further distance from Sun)More visible features (thinner haze, less dense clouds lie higher)
13Internal Structures – models that fit the data Metallic hydrogen is like liquid metalUranus/NeptuneSaturnJupiterIncreasing temperature and pressure deeper in coreJupiter bulges at radius (7% larger)Saturn less asymmetric – larger core – same basic overall structureUranus/Neptune have a high density “slush” below cloud level - compressed water clouds
14Pluto - and Charon Discovered in 1930 Charon (its moon) found in 1978 40 times the Earth’s distance from the Sun (40AU)No spacecraft flybys but New Horizons mission launched in January 2006 will fly by in July 2015.Only 20% the mass of our MoonSimilar in mass and size to Neptune’s large moon TritonProbably formed in the Kuiper belt (comet birth place)Highly inclined orbital planeHST image of Pluto
16Planet Travel Brochure Each group of 2 needsA travel brochureImportant information on your planetBe creative!You will be graded as a group, so choose wisely. (10pts)
17Planet Travel Brochure (10pts) Criteria: a) Cover page must have the planet name b) Draw a picture of the planet plus two other pictures c) Include the following facts: distance from the Sun, diameter, how many days in a year, surface temperature, atmosphere composition d) Cost of traveling there, living conditions, things to do (be creative) e) Create mock interviews with recent travelers (mock testimony) f) Must be colored and aesthetic looking
19Kuiper Belt Objects compared The discovery of Eris in 2005 showed that Pluto was not unique. These objects, along with Pluto, seem to be the largest of the Kuiper Belt objects.
20The Earth The Moon solid inner core, liquid outer core atmosphere ~ 50km thickmagnetosphere – charged particles in magnetic fieldThe Moonno hydrosphere, atmosphere or magnetospheresimilar interior regions as Earth but no liquid core
21Tidal Effects of the Moon on Earth Even though the Sun exerts greater gravitational force on the Earth, tidal effects of the Moon are greater due to its closenessGravitational force exerted by the Moon is different on different parts of the EarthThe moon pulls the waterThe moon also pulls the EarthThis causes two bulges - one on the side facing the moon and one on the opposite side where the water is “left behind”Any point on the Earth experiences two high and low tides per day
22Over time, tides have the following effects on the Earth and the Moon Slowing the Earth’s rotation - the day is increasing by sec/century.Increasing the size of the Moon’s orbit - its distance from the Earth is increasing by 4 cm/year (2 inch/year)The moon is tidally locked to the Earth - the same side of the moon is always facing us (moon rotation period is the same as its orbital period)
23Lunar Surface - lack of atmosphere and water preserves surface features Maria – mantle material“seas” - darker areas resulting from earlier lava flowBasaltic, iron rich, high density (3300 kg/m3).Highlands – crust materialelevated many km above mariaAluminum rich, low density (2900 kg/m3).
24Craters Caused by meteoroid impacts Pressure to the lunar surface heats the rock and deforms the groundExplosion pushes rock layers up and outThe ejecta blanket surrounds the craterThe rate of cratering on the moon is determined from the known ages of the highland and maria regions.The Moon (and solar system?) experienced a sharp drop in the rate of meteoritic bombardment about 3.9 billion years ago (end of accretion era)The rate of cratering has been roughly constant since that time
25Formation of the MoonThe Moon has an overall composition and density quite difference from the Earth, but which resembles the material in the Earth’s mantle. This observation has led to the Impact Theory for the formation of the Moon.Mars-sized body hit the molten EarthParts of the mantle blew off and later formed the moonEarth had differentiated, so the mantle (from which the Moon formed) was already metal poor.
26The laws of planetary motion were determined by Johannes Kepler in The planets’ orbits obey these three laws based on the effects of gravity. The Sun’s gravitational pull dominates the motions of all planets.1st Law3rd Law2nd Law
27The distances to planets are known from Kepler’s Laws Sizes are determined from angular size and distance
28Masses (and densities) - determined through observing the gravitational effect of the planet on some nearby object (moons, nearby planets, satellites)Planets orbit the sun counter-clockwise as seen from the North Celestial Pole.All planets are roughly in the same orbital plane EXCEPT Mercury (and the dwarf planet Pluto).
29Terrestrial Planets Jovian Planets Mercury, Venus, Earth and Mars Close to SunSmall masses, radiiRocky, solid surfacesHigh densitiesSlow rotationWeak magnetic fieldNo ringsFew moonsJupiter, Saturn, Uranus, and NeptuneFar from SunLarge masses and radiiGaseous surfaceLow densitiesFast rotationStrong magnetic fieldMany ringsMany moons
30Comets Dirty snowballs - dust and rock in methane, ammonia and ice All light is reflected from the Sun - the comet makes no light of its ownThe nucleus is a few km in diameterHalley’s Comet in 1986Long period comets take up to 1 million years to orbit the Sun (may originate in the Oort cloud)Short period comets orbit the Sun in 200 years or less (e.g. Halley’s comet) – likely originate in the Kuiper belt and were kicked into an eccentric orbit
31Comet Temple 1 image obtained from Stardust satellite flyby on Feb 14, 2011 Crater with a small mound in the center indicates cometary nucleus is fragile and weak.Caused by impactor from Deep Impact mission in 2005 – found comet to be less icy and more dusty than expected...
32Spring Meteor showers: Lyrids – Apr 21/22 Eta Aquarids – May 5/6 Meteoroids – interplanetary rocky objects smaller than 100m (down to grain size). Consist mainly of iron and nickel with some carboncalled a meteor as it burns in the Earth’s atmosphereif it makes it to the ground, it is a meteoriteOld objects that appear to be as old as the solar system based on carbon datingMost meteor showers are the result of the Earth passing through the orbit of a comet which has left debris along its pathSpring Meteor showers:Lyrids – Apr 21/22Eta Aquarids – May 5/6
33Asteroids - rocks with sizes greater than 100m across Most asteroids remain in the Asteroid belt between Mars and Jupiter but about 2000 have orbits that cross Earth’s path.Based on known Earth-crossing asteroid orbits, it is estimated that 3 asteroids impact Earth every 1 million years!
34Asteroid Watch (Near Earth Object Program) Asteroid 2012 DA14 to Miss Earth on February 15, 2013Asteroid 2012 DA14 (about 45 meters) will pass within about 3.5 Earth radii of the Earth's surface
35Asteroids range in size from 100m to ~1000km They are composed of carbon or iron and other rocky material.The Asteroid belt is a group of rocks that appear to have never joined to make a planet (as opposed to having once been a planet that was later destroyed).Too little massDifferent chemical compositionsPlanet formation probably effected by nearby Jupiter’s strong gravity
36Earth’s Atmosphere nitrogen (78%) oxygen (21%) argon (0.9%) carbon dioxide (0.03%)Protects the surfaceRegulates temperatureVariables that describe a gas (P, ρ, T) are related by the Equation of StateP = (ρ/m)kTm is average mass per particle = 29 x mass of proton. For T = 300K at surface, ρ = 1.1 x 10-3 g/cm3Pressure at Earth’s surface (bottom of atmosphere) = 1 atm (or 1 bar)1 atm = 106 dyn/cm2 (Like 100 people standing on a square meter!)
37Earth’s InteriorCrust - 15 km thick (8 km under ocean km under continents)Mantle km thick (80% of planet volume)Core (3500 km outer core and 1300 km inner core) - High central density suggests the core is mostly nickel and ironDensity and temperature increase with depthDensity “jumps” between mantle and core but smoothly increases between inner and outer core – Why – changes in composition
38Evolution of the Solid Earth Accretion- material comes together to make the planet 4.6 Billion years ago (age of Sun). Earth was bombarded by interplanetary debris which made it hot.Differentiation - different densities and compositions to the earth - Earth was molten, allowing higher-density material to sink to the core (this core material still has temperatures like that of the Sun!)Crustal Formation - cooling and thickening of crust about 3.7 Billion years ago
39The Surface of the Earth The Earth is still active today: earthquakes, volcanoes…Sites of activity outline surface plates - plate tectonicsContinental drift - few cm/yearPlates collide head on (mountains) or shear past (earthquakes)Some plates are separating (under Atlantic) - new mantle material wells up between theConvection of warm mantle material responsible for tectonicsSites of earthquakes / volcanoes in the past 100 years
40Earth’s Magnetosphere – space influenced by Earth’s magnetic field Magnetic field lines run from the south to north magnetic polesMagnetic poles are close to (but not the same as) the axis polesThe field is distorted by the solar windField caused by the rotation of the planet coupled with the electrically conducting liquid metal core = dynamo effectAurora BorealisNorthern Lights – caused when the charged particles escape the magnetic field and collide with Earth’s atmosphere near the poles
41Recycle Your Old Cell Phones Reduce mining in DR CongoSave the environment2 points extra credit per cell phone (applicable to quiz or test)Broken, unused, cracked screen – will accept in any condition