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Formation of Our Solar System
By the Lunar and Planetary Institute
For Use in Teacher Workshops
Image: Lunar and Planetary Laboratory: http://solarsystem.nasa.gov/multimedia/display.cfm?IM_ID=178
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 athttp://solarsystem.nasa.gov/multimedia/display.cfm?IM_ID=175
Some more data to explain:
4. Most planets rotate in this same direction
NASA images edited by LPI
Mercury 0° Venus 177° Earth 23° Mars 25°
Jupiter 3° Saturn 27° Uranus 98° Neptune 30°
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.cfm?IM_ID=178
How Did We Get a Solar System?
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/
Image: LPI
Concentrations of dust and gas in the cloud; material starts to collect (gravity > magnetic forces)
How Did We Get a Solar System?
Hubble image at http://hubblesite.org/newscenter/archive/releases/nebula/emission/2005/35/image/a/
Image: LPI
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/timeline/gallery/slide_1.html
How Did We Get a Solar System?
NASA artwork at http://en.wikipedia.org/wiki/Image:Ra4-protoplanetary-disk.jpg
•Rotating, flattening, contracting disk - solar nebula!
Equatorial Plane
Orbit Direction
•After ~10 million years, material in center of nebula hot enough to fuse H
•“...here comes the sun…”
How Did We Get a Solar System?
NASA/JPL-Caltech Image at http://www.nasa.gov/vision/universe/starsgalaxies/spitzer-20060724.html
How Did We Get a Solar System?
Hubble photo at http://hubblesite.org/newscenter/archive/releases/star/protoplanetary-disk/2005/10/image/a/layout/thumb/
•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
How Did We Get a Solar System?
Inner Planets:•Hot – Silicate minerals, metals, no light elements, ice
•Begin to stick together with dust clumpsImage: LPI http://www.lpi.usra.edu/education/timeline/gallery/slide_3.html
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 acrossImage: LPI http://www.lpi.usra.edu/education/timeline/gallery/slide_3.html
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/timeline/gallery/slide_4.html
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/timeline/gallery/slide_5.html
The Asteroid Belt? Should have been a planet instead of a
debris belt? Jupiter kept it from forming
How Did We Get a Solar System?
Eros image athttp://solarsystem.nasa.gov/multimedia/gallery.cfm?Category=Planets&Object=Asteroids&Page=1
Beyond the Gas Giants - Pluto, Charon and the Kuiper Belt objects
Chunks of ice and rock materialLittle time / debris available to make a planet
– slower!!
How Did We Get a Solar System?
Play Doh Activity
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/multimedia/display.cfm?IM_ID=168
Pause to recall the Play Doh accretion activity
But wait, there’s more …. We can differentiate!
When did Our Solar System Form … How do We Know?
Image: Lunar and Planetary Laboratory: http://solarsystem.nasa.gov/multimedia/display.cfm?IM_ID=178
When Did the Solar System Form?
• 4.56 billion years ago
• How do we know? (evidence for formation)
Meteorite photo by Carl Allen athttp://ares.jsc.nasa.gov/Education/Activities/ExpMetMys/..%5C..%5CSlideSets/ExpMetMys/Slides1-9.htm
•Lunar samples - 4.5 to 4.6 Ga•Meteorites - 4.56 Ga•Earth – 3.9 (or 4.4 Ga)
Lunar meteorite athttp://meteorites.wustl.edu/lunar/stones/mac88105.htm
How Do We Know How Our Solar System Formed?
Solar System Samples
Meteorites
Image: http://solarsystem.nasa.gov/multimedia/display.cfm?IM_ID=2093 And http://nssdc.gsfc.nasa.gov/photo_gallery/photogallery-asteroids.html
• 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 Return1/15/2006
• StardustPassed through Comet Wild 2 Coma 1/2004
Stardust image athttp://stardust.jpl.nasa.gov/news/news97.html
Info and images at http://deepimpact.jpl.nasa.gov/index.cfm
We Can Also Look Around ….
Close-up of "Proplyds" in Orion
Thanks Hubble!
Hubble images athttp://hubblesite.org/newscenter/archive/releases/nebula/emission/1994/24/image/a/ and
http://hubblesite.org/newscenter/archive/releases/nebula/emission/1994/24/image/b/
Comets
• Dirty snowballs - small objects of ice, gas, dust, tiny traces of organic material
Image from: http://antwrp.gsfc.nasa.gov/apod/ap000805.html
Comet Parts
Nucleus, ComaDust tail – white, “smoke,” reflects sun. 600,000 to 6 million miles longIon tail – Solar UV breaks down CO gas, making them glow blue. 10’s of millions of miles
Image from http://hubblesite.org/newscenter/archive/releases/2004/52/image/a/
Image credit: K. Jobse, P. Jenniskens and NASA Ames Research Center http://solarsystem.nasa.gov/multimedia/display.cfm?IM_ID=903
Naming Comets
NASA/ JPL image of Comet Halley at http://www.solarviews.com/cap/comet/haldet.htm
Where do Comets Originate?
What’s in a Tail?
Image credit: K. Jobse, P. Jenniskens and NASA Ames Research Center http://solarsystem.nasa.gov/multimedia/display.cfm?IM_ID=903
Comet – Planet Interactions
Image from http://www2.jpl.nasa.gov/sl9/image3.html
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