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

…………………………