he Great Galaxy in Andromeda - Credit & Copyright: John P. Gleason,Celestial Images ASTRONOMY EDUCATION & OUTREACHhttp://casswww.ucsd.edu/archive/public/astroed.html#TUTORIALUniversity of California, San DiegoCenter for Astrophysics & Space Scienceshttp://casswww.ucsd.edu/archive/public/tutorial/scale.htmlSpace calendarhttp://www2.jpl.nasa.gov/calendar/ http://hubblesite.org/gallery/ album/solar_system/ http://solarsystem.nasa.gov/index.cfm http://solarsystem.nasa.gov/index.cfm
Chapter 5. The Solar System. Main points:1-Overview of solar system: 2- Origin of the solar system.a- Planets. a- Solar nebula theory.b-Space debris. b- Extra- solar planets Sizes are to scale, but distances are not.
Chapter 5. The Solar System. Main points:If the sun were a large grapefruit (r~ 7 cm), theEarth would be a pinhead 15 meters away.Sizes are to scale, but distances are not.
Solar System Neptune UrThree types of Asteroid an u splanets: Belt Sa t urTERRESTRIAL Ju nJOVIAN pit Ma erAND rs EaDWARF . Ve rth Me nu rcu s ry
Terrestrial Jovian Planets. Planets. Moon Uranus Jupiter Neptune Venus Mars SaturnMercury Pluto Earth The Sun contains about 99.8% of the mass of the Solar System
July 17, 2009: Fortytwo years ago,Apollo astronautsset out on a daringadventure toexplore the Moon.They ended updiscovering theirown planet.
Some general characteristics of the planets.Planets revolve around the sun, counterclockwiseas seen from the north pole, in the same directionand almost in the same plane.
Mercury’s orbit is tipped 7o and Pluto’s 17.2o offthe plane of the ecliptic or plane of the solar system.
Inclination of planets to the plane of the ecliptic. Terrestrial planets Venus rotates backwards
Inclination of planets to the plane of the ecliptic. Saturn 27 0 Jovian planets Uranus rotates on its side. •Sun’s axis is tipped 7o .
Of the following OBJECTS, the orbit of _______,is the most inclined with respect to the plane ofthe solar system.a- Venus b- Earth c- Marsd- Jupiter e- Pluto
The Terrestrial planets are insidethe orbit of the asteroid belt.
Terrestrial planets and their moons.Counting from left to right Venus is the ______ object.a- first b- second c- third d- fourth
I am the planet _____and the large scarf ofabout _____ km and_____ km deep,along the equator iscalled ________.My average surfacetemperature is only_______degrees.
I am the planet MARS and the large scarf of about 4 000 km and 200 km deep, along the equator is called Valles Marineris. My average surfaceOlympus V al temperature is onlyM on les M arin 210 K degrees. eris
Scientist believed that more than 4 billion years ago I had running water on my surface.Olympus V alM on les M arin If that is the case eris what went wrong with me and where is the water?
JOVIAN PLANETSJupiter, Saturn, Uranus and Neptune.
Comparing Terrestrial and Jovian planets Terrestrial Jovian Earth has the Jupiter: 11 Earth’s radius. largest radius Saturn: 9 “ r = 6 380 km. Uranus: 4 “Radius Neptune: 4 “
Comparing Terrestrial and Jovian planets Terrestrial JovianOrbital Mercury 0.39 Jupiter: 5radius in Venus 0.7 Saturn: 10AU Earth 1 Mars 1.5 Uranus: 19 Neptune: 30 orbital Mer. 0.24 Jupiter 11.86period Ven. 0.65 Saturn 29.542 (years) Earth 1 Uranus 83.75 Mars 1.88 Neptune 163.7 P2 = a3
Comparing Terrestrial and Jovian planets Terrestrial Jovian solid, rich in metals: Low % in metals and Fe, Al, Mg, Ni and silicates. silicates ( rocks).Composition Rich in gases , mostly hydrogen and helium. Low concentration of ices of water low melting materials Lots of ammonia (NH ), and 3 such us ices, water methane (CH4). and gasses Low concentrations of metals and silicates. Similar in composition to the sun. (Solar in composition)
Comparing Terrestrial and Jovian planets Terrestrial Jovian Hot molten core of silicate and metals Core: hot molten core of silicate (rocky core) and metals (rocky core)Structure Rocky mantle. Not defined Thin crust Not defined small atmosphere. large atmosphere.
Comparing Terrestrial and Jovian planets Terrestrial Jovian Density = High 3.9 to 5.4 Low 0.7 to 1.7 g/cm3 mass/volume g/cm3 Temperature From 273 to Cold atmospheres : 750 K less than 100 K Surface with numerous No surface. impact crates.Jupiter is 316 times the mass of the Earth and Saturn’s is 96.The rest of the planets together only have 33 Earth masses.
Mercury observed by Messenger, September 5, 2011
Comparing Terrestrial and Jovian planets Terrestrial JovianSidereal Mercury 58.64 days Jupiter 9.9 hPeriod of Venus Saturn 10.7 hrotation 243.18 days Uranus 17.2 h Earth 23.93 h Mars 24.62 h Neptune 16.1 h
Slow rotationLike the sun,the Jovianplanets have Fastdifferential rotationrotation. Slow rotation
Comparing Terrestrial and Jovian planetsAtmosphere Small or absent. Large Mercury lacks it. Terrestrial JovianRing No rings All have rings. The only rings visible from Earth are Saturn’s
Jupiter and Saturn have large internal pressurethat converts hydrogen gas to the liquid metallicstate, which is a good conductor of electricity. No boundary between liquid and gas. Jupiter Saturn Earth Hot molten core Metallic Liquid Hydrogen Atmosphere Atmosphere
Comparing Terrestrial and Jovian planets Terrestrial JovianMoons Few or no moons Many moons. Mars has two small Some are larger than and Earth one. our moon. Mercury and Venus: Lots of smaller moons no moons.
The Jovian Largestplanets havemany moons.Some arebigger thanour moon.
The Jovian planetsa- are similar in composition to the sun’s. a- are similar in composition to the sun’s.b- are giant planets and thus, they have largedensities.c- rotate very slowly.d- have cold cores, because they are far away fromthe sun.The presence or absence of atmosphere inplanets or asteroids is related to the escapespeed and surface temperature.
What is escape speed?The initial speed an objects needs toescape from the surface of a planet,star, moon or asteroid is the…….. Vo= 5 km/s Vo= 8 km/s Vo= 11.2 km/s mass Escape speed. VEscape = G radius
If the atoms and molecules of a gas movewith an average speed similar to the escapespeed , that gas is not present in the planet’satmosphere. Light molecules move faster than massive molecules, SO light molecules like hydrogen escape easily than the heavier ones, such as nitrogen or carbon monoxide.
Moon’s escape speed: 2 km/s Mercury’s escape speed: 4 km/sThe Moon and Mercury practically do not have anyatmosphere, because their surfaces get too hot andbecause they have low escape speed.
Recall: atoms and molecules move fast at hightemperature and slow at low temperature.Therefore, a small planet (low escape speed) withhigh surface temperature does not have anatmosphere, buta small planet with low surface temperature mighthave an atmosphere.
Titan cold is cold (100 K) and has Mercury is hot and atmosphere ( 500 K) and does not have any atmosphereMercury and Titan have similar volumes.
The Jovian planets are Jupiter’scold and have a large escape speed:escape speed therefore, 60 km/s ~ 5they have large Earth’satmospheres.
The stars and most planets have Magnetic Fields. South Magnetic pole re phe t os gneMa North Magnetic pole
The stars’ and planets’ magnetic field is dueto the Dynamo Effect. Convection Rotation + of a Magnetic = field. conducting medium M here sp ag ne to -The Earth, the Jovian planets, the sun and starshave magnetic fields.
ct i on ve on .C ne The sun zo rotates very fast and has a large convection zone, thus its magnetic field is intense.
The Earth’s magnetosphere is the region where the magnetic field is felt.Magnetosphere
The “solar wind” consist of charged particles, protons andelectrons escaping the sun’s upper atmosphere. Most of the particles in the solar wind are deflected by The charged particles from the sun interacts the Earth’s magnetosphere. A few particles spiral down with the air molecules producing the aurorae to the northern and southern latitudes forming the borealis or australis. “aurorae”
The charged particles in the solar wind interactwith the air molecules producing the auroraeborealis or australis.
Dwarf planets.In 2006 the International Astronomical Union(IAU) created a new category of planets: Dwarf planets.Name Distance Period (Y) Location from sun (AU)Ceres 4.6 4.6 Asteroid beltPluto 40 248 Kuiper beltHaumea 43 285 Kuiper beltMakemake 48 310 Kuiper beltEris 68 557 Kuiper belt
Three Dwarf Planet.. Ceres Pluto. Eris 2 247 Km 3 330 km 1000 kmIn the In the Kuiper beltAsteroid belt
Most of the dwarf planets are in the Kuiper belt, acold region, beyond the orbit of Neptune. Pluto Kuiper belt Eris
definitions:Icy Frozen water, gases and liquids such as:body: NH3 ammonia, CH4 methane, CO2 .Rocky A solid body rich in silicates,body: SiO2 and metals: Fe, Ni, Al, and Mg.
Space Debris: Meteorites Comets Asteroids Asteroids
Asteroids.Asteroids are the remains of the Mars‘planetesimals” that built the planets ~ 1.5 AU4.6 billion years ago!Where are the asteroids ?1- Most in the asteroid belt, Trojanwith orbits between 1.8AU and 3.3 AU.2- The Trojanasteroids, share the orbit Trwith Jupiter. oj an Jupiter 5.2 AU
The Apollo asteroids cross the Earth’s orbit. Many asteroids are in the Kuiper belt, beyond the orbit of Neptune Jupiter 5.2 AU
The asteroids, in the Kuiper belt, are large chunksof solid material, mainly icy, held by gravity.
There are basically Three types of Asteroids: C-type: carbonaceous, dark S-type: silicate (rocky) M-type: metallic; iron and nickel Low density ~ 1.3 g/cm3 and are not made of solid hard rock.
Asteroids observed by Galileo spacecraft inthe asteroid belt.
Most asteroids, haveirregular shapes, rotate ontheir axis and come indifferent sizes from large,to small (pebbles).The self-gravity of theasteroids is not enough topull them into a sphericalshape.About 100 000 havebeen identified so far. Ida rotating on its axis (HST).
Asteroid VestaVestaobserved byDawnspacecraftfrom adistance ofabout 3,200miles (5,200kilometers).on July 24,2011. Vesta ~ 600 km is the largest.
The spacecraft NEAR Shoemaker landed on theasteroid 433 Eros on February 2001.
These objects area- rocks from the moon b- dwarf planetsc- asteroids d- meteorites
Some asteroidsa- have been discovered orbiting Jupiterb- are similar in composition to Jupiterc- have running water on their surfaced- have diameters of 2 000 miles. e- none of the above.e- none of the above.
Bayeaux TapestryNorman Invasion of Comet of 15771066
Nucleus of comet Hartley 2 taken by NASAs EPOXI missionhttp://solarsystem.nasa.gov/index.cfm
NucleusIrregular fluffy (lots of voids) mixture ofices and pulverized rock (tiny particles).Ices: water, carbon dioxide, ammoniamethane and others.Rock: mainly pulverized silicates. nucleus of comet Hale, asDiameter of nucleus: from 10 to 50 km seen by Giottoand a density of (0.1 to 0.25) g/cm3. spacecraft.
The tails are produced Tailsby vaporizing ices anddust (rock) from thenucleus. Tail st Du ail T g as n or Io Comet West (1975))
Ion or gas tail consists of ionized gases. TheCO+ ions scatters the blue light more efficientlythan any other color and thus it looks blue Tail g as n or Io Comet West (1975)
The dust tail consist of tiny dusty particles. Thedust reflects all the visible light from the sunand looks white. Tail st Du
Tails point away from the sun pushed by the solar wind and solar radiation pressure.Tails are ~ 150 x106 km long.
Coma A Neat Comet. Kitt Peak National ObservatoryTenuous cloud of (C/2001 Q4 z)evaporated gas, (CO2, H, water, ammonia, etc)and dust with adiameter of more than 100000 km surrounding thenucleus.Surrounding the comais an invisible layer, orhydrogen envelope; thehydrogen may come Comafrom water molecules.
The comets havelong ellipticalorbits, becausethey come from faraway.Orbit of Comet Kohoutek, 1973-1974.http://history.nasa.gov/SP-4208/p391.htm
Oort cloudLong periodcomets (morethan 200 years ofreappearance) Suncome from theOort cloud andshort period- less The Kuiper Belt.than 200 years -comets comefrom the Kuiperbelt. Ort Cloud
Dimensions of the U 5x10 5 AOort cloud. AUInner radius 10 410 000 AU. SunExternal Planetaryradius region50 000 AU.
No directevidence of theOort cloud! Comets from the Oort cloud, come in any direction from the sky,
The Kuiper belt: region of icy planetesimals.Pluto, Charon, Triton, Quaoar, Sedna, Eris, andmore.
Why do cometsleave their In the Oort cloudhomes? occasional passing stars may perturb the orbits. In the Kuiper belt collision between them, or the gravitational force of Jupiter.
A solar system object, of rocky compositionand comparable in size to a small city is mostlikely.a- a meteorc- an asteroid b- cometc- an asteroid d- a planete- a meteoroid.
Short period comets and origin of meteors. First Second Third Hundredth Orbit Orbit Orbit. Orbit . ……The nuclei of comets are fragile and lose lotsof matter every time they come close to thesun leaving behind a trail of tiny particles.
Some definitionsMeteoroid. Small solidparticle moving towardsearth’s atmosphere. Meteor. Trail of light. “Shooting star’.Meteorite. A particle thatreaches earth’s surface.Many have been found.
Meteor Meteors and the meteor Showers. showers are produced when the Earth enters the trail of particles left behind by comets.The meteorscaptured by Earthincrease its mass200 tons per day. Meteors are related to comets!
Meteor showers,seem to comefrom the sameplace in space.The Leonidmeteor shower,(November 14-19), seems tocome from theLeonidconstellation.
1997 Leonids from OrbitAfter midnight the speedof the meteors and the The 1833 stormrotation of the Earthsspeed adds up improvingthe chance to see a meteor
Meteorites.Particles that reach earth’s surface are the Meteorites. Meteorites endure the high temperature caused by air’s friction . Meteorites appear to be fragments of asteroids and even of terrestrial planets. Iron-Ni, with ~ 7% Ni.
There are basically Three types of meteorites: C-type: carbonaceous, dark S-type: silicate (rocky) M-type: metallic; iron and nickelSo: three types of asteroids. Fe
Meteorite from thesurface of Mars. It washurled into space byand impact.
Which of the following is most likely relatedto comets?a- asteroidsb- meteoritesc- meteorsc- meteorsd- dwarf planetse- a & d.
Age of Solar System .- All objects in the solar system were formed around the same time.- The age of the meteorites gives the age of the solar system. Radioactive dating,Go to. http://lectureonline.cl.msu.edu/~mmp/applist/decay/decay.htm
Radioactive sample In ten hours at t = 0 hours Half life time - 10 hours. daughterThe age of rocks is found comparing the originalamount of radioactive (unstable) atoms and daughterabundance.
Examples of half life. Parent Daughter Half life years 238 U 206 Pb 4.5 billion 40 K 40 Ca, 40Ar 1.3 billion 226 Rb 87 Sr 47 billionHalf-life is the time in which half of theradioactive mass decays.
The meteorites and the rocks from the moon areabout 4.6 billion years old. This is the age of thesolar system.Most of the oldest rocks found on Earth are onlyabout 3.9 to 4.1 years old. The oldest rocks have been destroyed because the Earth is very active.
Decay of In 3 billion“Nonex” years how many particles of Nonex have decayed? a. 150 b. 1050 c. 220 c. 1050 d. 1000 1200 - 150 = 1050
Summary:Meteors: come from comets they are fragile andeasily burnt upon entering the atmosphere.Meteorites: come from asteroids or planets. They arehard and make it to Earth.Comets have highly elliptical orbits.Asteroids are solid with rocky composition (carbon,silicates and metals).Objects in the Kuiper belt are icy and very cold.The age of the solar system, about 4.9 billion years,is estimated from the age of the meteorites.
See this videohttp://www.youtube.com/watch?v=Uhy1fucSRQI