ASTRONOMY 8850:Planetary Sciences
Why Sciences?
How to do well inPlanetary Sciences
1. show up to class … and be present
2. participate in class
3. get/borrow the book Planetary Sciences by de Pater and Lissauer
4. find course website: www.astro.gsu.edu/~thenry/PLANETS
5. find Icarus online (or in the library)
6. choose 3 planetary topic(s) you are most interested in --- start project EARLY
7. do homework --- Solar System Explorers, quizzes, etc.
8. NAIL THE SEMESTER PROJECT
Solar System Explorers 01
Find Icarus online (or in the library).
Choose an article relevant to one of your 3 topics.
Print out the first page of the article.
Turn in single page (with your name on it) at the beginning of class TUESDAY, January 20.
Get 5 points in Solar System Explorers.
Solar System Inventory
• stars
• planets
• moons
• ring systems
• minor planets
• Centaurs
• Trans-Neptunian Objects
• comets
• dust
1
8
172a (JPL 2015 JAN 12)
4 (+1?)
670,480 (JPL 2015 JAN 12)
295 (JPL 2015 JAN 12)
1,644 (JPL 2015 JAN 12)
3,319b (JPL 2015 JAN 12)
a add 5 for Plutob any type
Nomenclature• terrestrials
Mercury, Venus, Earth, Marsmany moons
• joviansgas giants
Jupiter, Saturnice giants
Uranus, Neptune• minor planets
asteroidsMain BeltNear-Earth Objects (NEOs)Trojans (and Greeks and Hildas)
Trans-Neptunian Objects (TNOs)Plutinos (Classical) Kuiper Belt Objects
(KBOs)Centaurs Scattered Disk Objects (SDOs)
comets
Solar Family
How are they different?
Jovians and Terrestrials
Planetary Sciences 8
Planet Spacing
Planetary Sciences
Planet Orbits
The 7 Dwarfs (+ interlopers)
X
X X
Terrestrial Planet Surface
Planetary Sciences 12
Surface Variability
Jovian Planet “Surface”
Planetary Sciences
…we can land/work on surfaces
Planet Characteristics
locationspacingmasssizedensitycompositionsurfacealbedorotationmagneticsmoonsrings
0.4-1.5 AU 5.2-30.1 AU close wide 0.05-1.0 Earths 14.5-318 Earths 0.4-1.0 Earth radii 3.9-11.2 Earth radii 3.9-5.5 g/cm3 0.7-1.6 g/cm3
rocky gaseous/icy solid any? 0.1-0.7 0.4-0.5 slow fast none/weak strong (integrated) none/few many none all
Characteristic Terrestrial Jovian
obliquities (tilts)
Planetary Sciences 17
bizarre bar magnets
magnetospheresEarth’s is strongest terrestrial surface mag field = 0.3 G mag moment = 8x1025 G/cm3
enough to protect us from charged particles
Mercury’s, Ganymede’s wimpyVenus?, Io, Europa, Callisto inducedMars’ patchy crustal
Jupiter’s is strongest jovian surface mag field = 4.3 G mag moment = 20000X Earths Io plasma torus complicates affects all Galilean satellites
Sat/Ura/Nep surface mag fields similar strength to Earth’s
Planetary Sciences
Jupiter’s magnetotail
trends in the Solar Systemsize with distance from the Sun
composition with distance
spacing of planets with distance
# moons with planet mass
magnetic fields with mass
rotation speeds with mass
non-trends in the Solar Systemsurface gravities not radically different
obliquities do not behave
7 large moons are worlds of their own:
Moon, Io, Europa, Ganymede, Callisto, Titan, Triton
…………………………