Exam 3 Study GuideProvided is an outline of topics discussed during our third section. I’ve tried my best to organize topics effectively (Terms, Sections, People, and some miscellaneous Information.) It’s a lot to look at, but pace yourself and remember we won’t need to know everything. I hope the outline will be beneficial to the class. Good Luck and happy studying! ~Terms~asteroids- minor planets (usually between Mars and Jupiter)comets- remnants of early solar system with highly eccentric orbits-develop a tail when close to the sunmeteors- (shooting stars) mostly tiny particles burning up in the atmosphere(Orionids: Oct.21st, Eta Aquarids: May 6th) zodiacal light- light extending from the horizon to the ecliptic (faint cone of light)Gegenschein- type of faint light that shines opposite of the position of the sunsolar eclipse- (season lasts 32 days)lunar eclipse- more common, totality lasts over an hour(season lasts 22 days) AST 2003 1st EditionSaros cycle- eclipse cycle with a period of 223 synodic monthsannular eclipse- eclipse of the sun where a ring can be observedpartial eclipse- eclipse of the sun or moon where only partially is shadowednode- point where the path of the moon crosses the ecliptic synodic month- time between successive phasessynodic period- time it takes to show the same phase with relation to the Earth draconic month- time between two similar nodesanomalistic month- time for the moon to move to the same position in its eclipse sidereal month- true orbital rate of the moonsidereal period- time it takes a planet to orbit the sunprograde- moving west to eastretrograde- moving east to westelongation-angle between sun and planet greatest elongation- greatest angular distance that can be from the sunoccultations- when one object blocks out another conjunctions- when objects appear to be close togetherinferior conjunction- “the alignment of the Earth and a planet on the same side of the sun”superior conjunction-opposite side of the sun from the Earthcardinal points- (North, East, West, South)radiant- “the point in space from which a meteor shower appears to emanate”Trigon of Great Conjunctions- three consecutive conjunctions make a triangle (trigon)~Kepler’s laws of planetary motion~. 1. Planets orbit the sun in ellipses with the sun at one focus (orbits close to being circular) 2. A line connecting a planet to the sun sweeps out equal areas in equal time-Equation of Time on sundials-An Empirical (proven) Law-Used in calculating orbital paths 3. The square of a planets orbital period is proportional of the cube of its distance from the sun T(2) = R(3) (Years to orbit sun) = (AU)~Formation of the Solar System~. Patterson- associated with aging process through ancient rock,which helped confirm Earth’s age of about 4,550 million years . Descartes- “proposed that the solar system began as a massive cloud of gas and dust…and through external forces, conditions become intense enough to form a star at the center”. Laplace- proposed conversation of angular momentum (as nebula spin increases it collapses and changes shape into flattened disk)~Motion of the Moon~. -moves at an angular distance equal to its size in about an hour or 13 degrees a day. -shadows of the moon are best viewed at the terminator (best viewed at full phase) . -orbits earth in an ellipse (perigee-closest, apogee-farthest). -always has the same face pointing the Earth. -rises in the East, sets in the West. -waxing moon- the phases get “bigger” as the evening moves on (see diagrams page 10-2a). -waning moon- seen in the sky when the sun comes up then phases turn into waxing phases (see diagrams page 10-2a). -Aristarchus used lunar eclipses to estimate the size of the moon .. Why is there not an eclipse every month?. -Because of the tilt of the moon’s orbital path which cannot drift more than 5.2 degrees away from the ecliptic~Phases of the Moon~~Inner Planets~SUN- 93 million miles away-closest star-center of other planets orbit-half-way through its lifetimeMERCURY (Hermes/Messenger)- slightly larger than moon-weak magnetic field-“Mariner” only space probeVENUS (Aphrodite)- twin of Earth- high volcanic activity-only to spin opposite way- EARTH- 4500 million years old- well developed atmosphere- affected by the life existing on itMARS (Ares)- length of a day similar to Earth’s- has seasons- once had water- 2 moons (Phobos + Deimos) ~Outer Planets~JUPITER (Zeus)-metallic core-(H)strong magnetic field-moons: 61 in total… (Io, Europa, Ganymede, Callisto)SATURN (Cronus)-30 years to orbit sun-least densest planet-biggest moon is TitanURANUS -faint ring system detected using stellar occultation- 27 moons (ex:Miranda)NEPTUNE (Poseidon)- most distant of gas giants- interior of planet rotates faster than the atmosphere-faint ring- moon (ex: Triton)PLUTO- more like Kuiper belt object-most eccentric orbit-small moon (and 2 recently found): Charon- New Horizons probe 10-year journey-declares not a planet by the IAU (2006)-there are currently 3 dwarf planets (Pluto, Ceres, Eris)To be a planet….. It must orbit the Sun . It must be large enough to become spherical . It must clear out its orbit of other objects~Motion of the Planets~-Composition of protoplanets depends on location-density and temperature is greater near the center-larger planets form from gas molecules, because of the outer regions material condensing quickly-looping- motion of the planets movement due to Kepler’s 3rd Law (wandering among the stars)-occurs because the Earth is closer to the Sun, therefore moving faster in orbit (Mars moves the fastest)-size of the loop depends on distance from the sun~People~ Hipparchus-1st star catalogue and astronomer-precessionGalileo-discoveries supported Copernicus-made many discovers with homemade telescope(1609)-accused of heresy Ptolemy-Earth was stationary-sphere theory-“planets orbit the earth” or “Geocentric”Copernicus-sun at the center “Heliocentric”-created system (model)Tycho Brahe-meticulous/eccentric astronomer -invented new instruments to improve accuracy -was funded to build observatory -hired Kepler as an assistantWilliam Hershel (URANUS)-Known for his “discovery” of Uranus, which he originally thought was a comet- Was made court astronomer to king George and tried to name it George’s planet.Adams and Le Verrier (NEPTUNE)-predicted mass and orbit Airy, Galle (NEPTUNE)- caused controversy of who was pre-eminent in the