Download CHAPTER 6: The Solar System

CHAPTER 6:
The Solar System
COMPARITIVE PLANETOLOGY
Comparing and contrasting the properties of
the diverse worlds we encounter to
understand the conditions under which
planets form and evolve.
We need to understand how each
planet/object compares with our own, and
what each contributes to our knowledge of
the solar system as a whole.
CURRENTLY OUR SOLAR SYSTEM
1 Star (Sun)
8 Planets…… (9 if you count Pluto)
169 Moons Orbiting these planets
8 Asteroids
100 + Kuiper belt objects larger than 200 miles
A Myriad of Comets
OUTSIDE OF OUR SOLAR SYSTEM
2003 confirmed exoplanets (extra solar
planets)
4,656 Candidates
Our observations of the exoplanets provide
critical tests of modern theories of planet
formation
Scientists are asking questions like:
How did our solar system form?
Are there other planetary systems like ours?
Is life out there?
Overall Layout of our Solar System
All Orbits Except
Mercury’s are on
the same plane
Planets all on nearly
the same plane
Solar System facts
All the planets orbits are ellipses (sun foci)
All planets move on low eccentricity (except
mercury
Orbits are not evenly spaced out. Further
apart the further we get from the sun.
All planets orbit the Sun Counterclockwise
(CCW)
Solar system appears flat.
Terrestrial vs Jovian Planets
TERRESTRIAL / JOVIAN PLANETS
TERRESTIAL PLANETS:
Mercury, Venus, Earth, Mars
SMALL, DENSE & SOLID
JOVIAN PLANETS
Saturn, Jupiter, Uranus, Neptune
LARGE, LOW DENSITY, GASEOUS
TERRESTRIAL PLANETS (INNER PLANETS)
(Mercury, Venus, Earth, Mars)
Physical & Chemical properties are similar
All are within 1.5 AU of the sun
All are small with relatively low mass
Earth is the largest & most massive
All have rocky composition and solid surface
JOVIAN PLANETS (OUTER PLANETS)
(Saturn, Jupiter, Uranus, Neptune)
Physical & Chemical properties are similar to
each other, but very different from Terrestrial
All orbit far from the Sun
All are much larger than inner planets
Have no solid surfaces
Outer layers are composed of light gasses
Hydrogen and Helium
Differences in Terrestrial Planets
All 4 have Atmospheres, but they are totally
different (mercury- Vacuum / Venus – inferno)
Earth is the only one with Oxygen and Liquid
water on the surface
Surface Conditions (Barren vs Volcanic)
Earth / Mars rotate at almost the same rate (24
hours) Mercury / Venus take months & venus
rotates in the opposite direction
Earth / Mars have moons – Venus/ Mercury do not
Earth / Mercury have magnetic fields- Mars /
Venus do not
Terrestrial – Jovian Comparisons
TERRESTRIAL PLANETS
JOVIAN PLANETS
Close together near the sun
Widely spread far from sun
Small, Dense, Rocky
Large, Less Dense, Gaseous (H , HE)
Solid Surfaces
None (thicken with depth )
weak magnetic fields or none
Strong Magnetic Fields
Large Dense “terrestrial” Cores (10/15 times
earth)
Only 3 moons among them
Many moons (none are the same / none
like ours
No rings
All have rings
INTERPLANETARY MATTER
Cosmic “Debris” –
Asteroids (Large) – Kuiper Belt
Comets (Smaller) –
Meteoroids (Smaller)
Interplanetary Dust (Smallest)
INTERPLANETARY DUST
Large bodies collide and break apart, collide
again and break again….slowly ground into
microscopic particles of Dust.
Eventually settle into the Sun or are swept
away by Solar Wind (charged particles that
flow outward from the Sun)
Hard to detect in Visible Light… But easy in
Infrared
ASTEROIDS & METEOROIDS
Rocky Composition (like outer layers of
Terrestrial planets)
Difference between them is SIZE
Larger then 100M Asteroid / Smaller is a
Meteoroid
VERY IMPORTANT to our study of birth of our
solar system.
Material has hardly evolved since birth of our
solar system.
They conveniently crash onto the Earth
COMETS
Icy rather than Rocky (Some rock material)
1-10KM
Contain truly ANCIENT material. Material
changed LESS than Asteroids
Do not hit the Earth… they burn up
Haven’t been able to study them until
recently
Tails vaporize as they get close to the Sun
and we use Spectroscopic study to study
tails.
KUIPER BELT
Outer asteroid belt beyond Neptune
Icy comets fraction of KM to 1000KM
Small and Far so didn’t discover until mid 90’s
PLUTO CONTROVERSEY
Largest Kuiper Belt object or Planet?????
1930 planet… now doesn’t fit planet
classification by Mass and composition.
More in common with Jovian Moons then
Jovian or Terrestrial planets.
Discovered more Kuiper belt objects
comparable in size and at least one LARGER
then Pluto.
2006 R.I.P Planet Pluto… now Dwarf planet