The Formation of Our Solar System

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Slide 1

Formation of Our Solar System

By the Lunar and Planetary Institute For Use in Teacher Workshops

Image: Lunar and Planetary Laboratory:

Slide 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

Slide 3

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°

Slide 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:

Slide 5

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

Image: LPI

Slide 6

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

Image: LPI

Slide 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)

Slide 8

How Did We Get a Solar System?

NASA artwork at

Rotating, flattening, contracting disk - solar nebula!

Equatorial Plane

Orbit Direction

Slide 9

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

Slide 10

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