sekolah dasar

1
Formation of Our Solar System
By the Lunar and Planetary InstituteFor Use in
Teacher Workshops
Image Lunar and Planetary Laboratory
http//solarsystem.nasa.gov/multimedia/display.cf
m?IM_ID178
2

• Some data to explain
• 1. Planets isolated
• 2. Orbits circular / in same plane
• 3. Planets (and moons) travel along orbits in
  same direction. same direction as Sun rotates
  (counter-clockwise viewed from above)

Lunar and Planetary Institute image
at http//solarsystem.nasa.gov/multimedia/display.
cfm?IM_ID175
3
Some more data to explain 4. Most planets rotate
in this same direction
Mercury 0 Venus 177 Earth 23
Mars 25
Jupiter 3 Saturn 27
Uranus 98
Neptune 30
NASA images edited by LPI
4

• And some more data to explain
• 5. Solar System highly differentiated

Terrestrial Planets (rocky, dense with density
4-5 g/cm3) Jovian Planets (light, gassy,
H, He, density 0.7-2)
Images Lunar and Planetary Laboratory
http//solarsystem.nasa.gov/multimedia/display.cf
m?IM_ID178
5
How Did We Get a Solar System?
Image LPI
Huge cloud of cold, thinly dispersed interstellar
gas and dust threaded with magnetic fields that
resist collapse
Hubble image at http//hubblesite.org/newscenter/
archive/releases/nebula/emission/2006/41/image/a/
6
How Did We Get a Solar System?
Image LPI
Concentrations of dust and gas in the cloud
material starts to collect (gravity gt magnetic
forces)
Hubble image at http//hubblesite.org/newscenter/
archive/releases/nebula/emission/2005/35/image/a/
7
How Did We Get a Solar System?
Gravity concentrates most stuff near
center Heat and pressure increase Collapses
central proto-sun rotates faster (probably got
initial rotation from the cloud)
Image LPI http//www.lpi.usra.edu/education/timel
ine/gallery/slide_1.html
8
How Did We Get a Solar System?

• Rotating, flattening, contracting disk - solar
  nebula!
• Equatorial Plane
• Orbit Direction

NASA artwork at http//en.wikipedia.org/wiki/Image
Ra4-protoplanetary-disk.jpg
9
How Did We Get a Solar System?

• After 10 million years, material in center of
  nebula hot enough to fuse H
• ...here comes the sun

NASA/JPL-Caltech Image at http//www.nasa.gov/vis
ion/universe/starsgalaxies/spitzer-20060724.html
10
How Did We Get a Solar System?

• Metallic elements (Mg, Si, Fe) condense into
  solids at high temps. Combined with O to make
  tiny grains
• Lower temp (H, He, CH4, H2O, N2, ice) - outer
  edges
• Planetary Compositions

Hubble photo at http//hubblesite.org/newscenter/
archive/releases/star/protoplanetary-disk/2005/10/
image/a/layout/thumb/
11
How Did We Get a Solar System?

• Inner Planets
• Hot Silicate minerals, metals, no light
  elements, ice
• Begin to stick together with dust ? clumps

Image LPI http//www.lpi.usra.edu/education/timel
ine/gallery/slide_3.html
12
How Did We Get a Solar System?

• Accretion - particles collide and stick together
  or break apart gravity not involved if small
  pieces
• Form planetesimals, up to a few km across

Image LPI http//www.lpi.usra.edu/education/timel
ine/gallery/slide_3.html
13
How Did We Get a Solar System?

• Gravitational accretion planetesimals attract
  stuff
• Large protoplanets dominate, grow rapidly, clean
  up area ( takes 10 to 25 My)

Image LPI http//www.lpi.usra.edu/education/timel
ine/gallery/slide_4.html
14
How Did We Get a Solar System?

• Outer Solar System
• Cold ices, gases 10x more particles than
  inner
• May have formed icy center, then captured lighter
  gases (Jupiter and Saturn first? Took H and He?)

Image LPI http//www.lpi.usra.edu/education/timel
ine/gallery/slide_5.html
15
How Did We Get a Solar System?

• Early burst of solar wind - sweeps debris out of
  system
• Gravitational accretion of gas for protoplanets
  in the coolest nebular parts

Image LPI http//www.lpi.usra.edu/education/timel
ine/gallery/slide_5.html
16
How Did We Get a Solar System?

• The Asteroid Belt
• ? Should have been a planet instead of a debris
  belt? Jupiter kept it from forming

Eros image at http//solarsystem.nasa.gov/multimed
ia/gallery.cfm?CategoryPlanetsObjectAsteroidsP
age1
17
How Did We Get a Solar System?

• Beyond the Gas Giants - Pluto, Charon and the
  Kuiper Belt objects
• Chunks of ice and rock material
• Little time / debris available to make a planet
  slower!!

18

• Play Doh Activity

19
Early in the Life of Planets

• Planetesimals swept up debris
• Accretion Impacts HEAT
• Eventually begin to melt materials
• Iron, silica melt at different temperatures
• Iron sank density layering

Image from LPI http//solarsystem.nasa.gov/multim
edia/display.cfm?IM_ID168
20
Planetary Interiors
Image from LPI http//solarsystem.nasa.gov/multim
edia/display.cfm?IM_ID168

• Differentiation
• Separation of homogenous interior into layers of
  different compositions
• Early hottest time dense iron-rich material ?
  core
• Releases additional heat
• Leaves mantle with molten ocean enriched in
  silica
• Crust eventually forms from lightest material

21
Planetary Interiors
Image from LPI http//solarsystem.nasa.gov/multim
edia/display.cfm?IM_ID168

• Differentiation
• Continues!
• Radioactive decay primary heat source
• Partial melting of mantle material ? rising magma
  ? volcanoes / lava flows

22

• Pause to recall the Play Doh accretion activity
• But wait, theres more .
• We can differentiate!

23
When did Our Solar System Form How do We Know?
Image Lunar and Planetary Laboratory
http//solarsystem.nasa.gov/multimedia/display.cf
m?IM_ID178
24
When Did the Solar System Form?

• 4.56 billion years ago
• How do we know? (evidence for formation)

• Lunar samples - 4.5 to 4.6 Ga
• Meteorites - 4.56 Ga
• Earth 3.9 (or 4.4 Ga)

Lunar meteorite at http//meteorites.wustl.edu/lun
ar/stones/mac88105.htm
Meteorite photo by Carl Allen at http//ares.jsc.n
asa.gov/Education/Activities/ExpMetMys/..5C..5CS
lideSets/ExpMetMys/Slides1-9.htm
25
How Do We Know How Our Solar System Formed?
26
Solar System SamplesMeteorites
Image http//solarsystem.nasa.gov/multimedia/disp
lay.cfm?IM_ID2093 And http//nssdc.gsfc.nasa.gov
/photo_gallery/photogallery-asteroids.html
27

• Earliest history of Solar System - chemical and
  physical info about formation and building blocks
  of planets (rest of stuff was pulled into the Sun
  or other planets.)
• Sample Return
• 1/15/2006
• Stardust
• Passed through Comet Wild 2 Coma 1/2004

Stardust image at http//stardust.jpl.nasa.gov/new
s/news97.html
Info and images at http//deepimpact.jpl.nasa.gov/
index.cfm
28
We Can Also Look Around .
Close-up of "Proplyds" in Orion Thanks Hubble!
Hubble images at http//hubblesite.org/newscenter/
archive/releases/nebula/emission/1994/24/image/a/
and http//hubblesite.org/newscenter/archive/relea
ses/nebula/emission/1994/24/image/b/
29
Comets

• Dirty snowballs - small objects of ice, gas,
  dust, tiny traces of organic material

Image from http//antwrp.gsfc.nasa.gov/apod/ap000
805.html
30
Comet Parts
Image from http//hubblesite.org/newscenter/archiv
e/releases/2004/52/image/a/
Image credit K. Jobse, P. Jenniskens and NASA
Ames Research Center http//solarsystem.nasa.gov/
multimedia/display.cfm?IM_ID903
Nucleus, Coma Dust tail white, smoke,
reflects sun. 600,000 to 6 million miles
long Ion tail Solar UV breaks down CO gas,
making them glow blue. 10s of millions of miles
31
Naming Comets
NASA/ JPL image of Comet Halley at
http//www.solarviews.com/cap/comet/haldet.htm
32
Where do Comets Originate?
33
Whats in a Tail?
Image credit K. Jobse, P. Jenniskens and NASA
Ames Research Center http//solarsystem.nasa.gov/
multimedia/display.cfm?IM_ID903
34
Comet Planet Interactions
Image from http//www2.jpl.nasa.gov/sl9/image3.ht
ml