1. Formation of Our Solar System
How do we know?
Shape of our solar system
Differences among the planets
Oldest planetary surfaces
Asteroids, meteorites, and comets.

2. A Collapsing Interstellar Cloud
Formation of Our Solar System
A Collapsing Interstellar Cloud
Interstellar Clouds:
Stars and planets form from clouds of gas and dust.
The interstellar clouds are made mostly of:
hydrogen and helium

3. A Collapsing Interstellar Cloud
Formation of Our Solar System
A Collapsing Interstellar Cloud
As a result of gravity…
interstellar gas starts to condense.

4. A Collapsing Interstellar Cloud
Formation of Our Solar System
A Collapsing Interstellar Cloud
The collapse starts slow, then accelerates
Cloud becomes much denser at its center.

5. Sun and Planet Formation
Formation of Our Solar System
Sun and Planet Formation
The Solar Nebula:
A rotating disk of dust and gas.
The center becomes the Sun.

6. Sun and Planet Formation
Formation of Our Solar System
Sun and Planet Formation
As the disk began to cool, different elements and compounds were able to condense depending on their distance from the Sun
determined compositions of the forming planets.
Hotter
Cooler

7. Sun and Planet Formation
Formation of Our Solar System
Sun and Planet Formation

8. Sun and Planet Formation
Formation of Our Solar System
Sun and Planet Formation
The Growth of Objects
Planetesimals : formed as smaller particles collided and stuck together.

9. Asteroids Pieces of Asteroids
Formation of Our Solar System
Asteroids
Pieces of Asteroids
As the asteroids orbit, they occasionally collide and break into fragments.
A meteoroid is a asteroid fragment or other material that enters Earth’s atmosphere.
A meteor is the streak of light produced when a meteoroid burns up in Earth’s atmosphere.
A meteorite is part of a meteoroid, that does not completely burn up, that collides with the ground.

10. Comets Periodic Comets
Formation of Our Solar System
Comets
Periodic Comets
Meteor showers occur when Earth intersects a cometary orbit and numerous particles from the comet burn up upon entering Earth’s upper atmosphere.
“Shooting stars”

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