ASTR 1345 Lecture Test 3
Axial tilts and seasons on outer planets (Class Slide) (Note: You also need to know the day and night cycle's relation with seasons on Uranus)
- Jupiter 3degrees no seasons, Saturn: 26.7degrees summers are cold and winters are worse, Uranus: 97.9degrees extreme seasons, Neptune: 29.6degrees all seasons much longer and colder.
Orbits of asteroids (Slides and Sec 9-5): Apollo (or Aten), Amor, and Trojan asteroids
-Apollo: Crosses Earth's orbit. -Amor: Crosses Mars's orbit. -Trojan: Trapped at Jupiter's Lagrange.
Features of Neptune (P 271): belts, zones, the great dark spot, storms, winds (Note: All outer planets exhibit differential rotation)
-Belts & Zones: Have a banded blueish appearance due to methane absorbing red light. -Great Dark Spot: Half as large as Jupiter's Great red spot. Located at same latitude on Neptune as the Great Red spot. Rings: Methane ice.
Features of Saturn (Sec 8-9): belts and zones with less contrast, storms, winds (occasionally)
-Belts and zones with less contrast: Lack the colorful contrast visible on Jupiter. -Storms: Move at speeds of 1600 km/h which is some 10 times faster than Earth's jet streams and 3 times faster than the fastest winds on Jupiter.
Axial tilts and seasons on inner planets (Class slide)
Mercury: 0degrees no seasons, Venus: 177degrees no seasons, Earth: 23degrees all seasons, Mars: 24degrees all season(same as Earth)
Features of Jupiter (Sec 8-1): belts, zones, the great red spot, white ovals, winds, differential rotation
-Belts: Jupiter's cloud pattern (dark reddish bands). -Zones: Cloud pattern alternating with belts (light colored bands). Are white due to ammonia vapor at their tops. -Great red spot: Changes dimensions, is about 25,000 km long by 12,000 km wide. Two Earth's could fit inside. First observed in 1656 by English scientist Robert Hooke or Italian astronomer Giovanni Cassini. -White Ovals: Rotating storms similar to hurricanes. -Winds: Winds on the north side of Great red spot flow westward. Winds on the south of the Great red spot flow eastward. Winds within the Great red spot circulate counterclockwise.
Comets and their composition (P 294)
-Comets are made up of Ice, dust, rock, and frozen gases.
Surface features of Mercury (Sec 7-1): Scarps, spiderlike craters, mountains etc.(Note: Mercury's surface features are similar to our Moon, such as mountains and craters etc. Caloris Basin on Mercury is pretty similar to Orientale basin on the Moon. But some feature we have on Mercury, but not on the Moon and vice-versa, for example, maria exist on Moon, not on Mercury.))
-Craters: Densely packed like the craters on the moon. Produced by impacts 800million years ago. -Scarps: Floors of crater were flooded by lava and formed scarps after the lava cooled. -Mountains: Caloris Basin
Asteroids: definition and physical properties (Slides and Sec 9-3) (Note: Asteroids are also called minor planets or planetoids.)
-Definition: Small rocky objects that revolve around the sun also referred to as minor planets or planetoids. -Physical properties: Tens to hundreds of km in diameter. Irregular in shape. All show craters and dust, some show fractures. Some have satellites.
Spacecraft Galileo's visit to asteroids Gaspra and Ida (Sec 9-4), spacecraft NEAR's visit to asteroid Eros (Sec 9-5) (Note: You don't need to remember the details or physical properties of individual asteroids.)
-Gaspra and Ida: Ida's surface is more heavily cratered than Gaspra's surface, hence is much older. Ida is also bigger than Gaspra (60 km compared to 20 km). -Eros: Spacecraft NEAR shows that Eros is a chunk of rock and metal. Heavily cratered body.
Features of Uranus (Sec 8-14): belts, zones, hazy atmosphere, storms, winds
-Hazy atmosphere: Hydrogen atmosphere, has traces of methane, huge towering clouds. -Belts and zones: Has traces of belts and zones. Clouds go around the planet once every 16 1/2 hours.
Orbits of comets and development of dust and ion tails (Sec 9-7)
-Ion tails: Positively charged ions from the coma are swept away from the sun by solar wind to form ion tails. -Dust tails: Are formed when sunlight strikes dust particles that have been freed from the comet's evaporating nucleus.
Magnetic fields of outer -planets (Class slides)
-Jupiter: 19,000x Earth's field. -Saturn: 570x Earth's field. -Uranus: 50x Earth's field. -Neptune: 35x Earth's field
Origin and orbits of comets (Sec 9-9): Kuiper belt (short-period comets), Oort cloud (long-period comets)
-Long period comets: Have such eccentric orbits that they leave the inner solar system after one pass by the sun and take tens of thousands up to millions of years to return. -Short period comets: Long period comets turn into short period comets, orbiting the sun in fewer than 200 years. -Orbit of comets: Comets are highly elliptical and tend to be inclined relative the ecliptic.
Current space missions to Mars (Class Slides)
-Mars is host to seven functioning space crafts. -Five in orbit: 2001 Mars Odyssey, Mars Express, Mars Reconnaissance Orbiter, MAVEN and Mars Orbiter Mission. -Two on the surface: Mars exploration Rover Opportunity and Mars science laboratory curiosity.
Meteors, Meteoroids, Meteorites (P 304, Sec 9-10, 9-11, 9-12): their properties and differences
-Meteoroids: Rocky and metallic debris smaller than asteroids and are scattered throughout solar system. -Meteors: Meteoroids being vaporized in atmosphere. -Meteorites: Remnants of meteoroids that land intact.
Structure of Comets (Sec 9-7): nucleus, coma, tail , hydrogen envelop
-Nucleus: Solid cometary body, typically between 1 and 10 km across. -Tail: formed from coma gases and dust pushed outwards by radiation and particles from the sun. -Coma: Forms an atmosphere around the nucleus.
Plutoids/Dwarf Planets (Slides and Sec 9-1, 9-2): Order of sizes and distances (no need to memorize the actual numbers), space mission to Pluto (New Horizon); facts about Pluto and its surface features
-Order of sizes and distances: Eris, Pluto, Haumea, Makemake, Ceres. -Space mission to Pluto: NASA launched New Horizons spacecraft in 2006. -Surface features of Pluto: Changes in colors & brightness.
Rings of Saturn* (Sec 8-10): names of rings and gaps, composition, role of shepherd satellites, information about moonlets, spokes etc., why do these rings happen to appear and disappear
-Rings names: A-ring, B-ring, C-ring, F-ring. Saturn is tilted 27 degrees, so rings are seen at various angles. -Gap Names: Cassini division, Encke division, Keeler gap. -Role of Shepherd satellites: Shepherd's are what keep the division clear of small debris. -Moonlets: Often cause the ring ices to develop ripples. -Spokes: Electrically charged particles that are lifted out the ring plane caused by Saturn's magnetic field.
Surface features of Mars (Sec 7-8, 7-9, 7-12): Great canyon: Valles Marineris, the largest mountain in the solar system: Olympus Mon, dried-up riverbeds, dry lakes, hematite rocks, gullies, sand dunes, polar ice (dry ice CO2) caps, human face like features(Note: The surface in the northern hemisphere of Mars is smoother, less cratered and, hence, younger. On the other hand, southern hemispher's surface is older and have highlands (mountains and plateaus) and is full of craters.)
-Valles Marineris: Runs parallel to Martian equator. Stretches over 4000 km, 1/5th the circumference of Mars. Begins with fractured terrain west and ends with ancient-cratered terrain in east. -Olympus Mon: Size of Missouri. Rises 26km (16mi) high, 3x the size of mount Everest. -Polar ice caps: In winter: Large ice cap made of frozen carbon dioxide. In summer: Dry ice melts leaving smaller ice caps. -Sand Dunes: Formed by blown dust similar to those on Earth. -Dried Rivers: Winding Canyons. Similar to those on Earth. -Dry Lakes: Similar to those on Earth. -Gullies: Formed by water running down crater walls. -Hematite Rocks: Usually formed in water.
Surface features of Venus (Sec 7-7): atmospheric composition and what makes Venus the hottest planet; volcanic mountains (shield volcanos): Maat Mons, Saps Mons, Sif Mons, and Gula Mons; Continents: Ishtar Terra and Aphrodite Terra, Lada Terra; rift valleys, shield volcanoes
-What makes Venus the hottest planet: Carbon dioxide atmosphere acts as a "greenhouse" effect trapping heat from the sun. -
The physical properties (Class slides, and Sec 7-15): Sizes, distances, and densities(Note: You should know the comparison of the physical properties with those of the Earth and also among themselves and with outer planets.)
.-Inner planet sizes: Mercury is 38% the size of Earth, Venus is 95% the size of Earth, Moon is 25% size of Earth, Earth has a 6400km radius, Mars is 50% size of Earth. -Outer planet sizes: Jupiter is 11x bigger than Earth, Saturn is 9x bigger than Earth, Uranus is 4x bigger than Earth, Neptune is 3.8x bigger than Earth, Pluto is 0.17x bigger than Earth. -Distances: -Densities: Saturn 700 , Uranus 1200 , Jupiter 1300 ,Neptune 1700 ,Pluto 2000 ,Mars 3900 ,Venus 5300 ,Mercury 5400 ,Earth 5500. (In Order)
Magnetic fields of inner planets (Class slides)
Mercury: weak magnetic field (0.1 times Earths magnetic field, Venus: no magnetic field, Earth: strong global magnetic field, Mars: weak global magnetic at least at 9 places
Space missions to Mercury: Mariner 10 and Messenger (Class Slides)
Launched in Nov. 1973: Went near Mercury in March 1974, Sept. 1974, and March 1975
Collision of comet Shoemaker-Levy with Jupiter (Sec 8-3)
Originally orbited Jupiter, was torn apart by Jupiter's gravitational force, broke into 21 pieces.