formation of our solar system how do we know? –shape of our solar system –differences among the...
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Formation of Our Solar System
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.
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
Formation of Our Solar System
A Collapsing Interstellar Cloud• As a result of gravity…
interstellar gas starts to condense.
Formation of Our Solar System
A Collapsing Interstellar Cloud
Formation of Our Solar System
– The collapse starts slow, then accelerates
– Cloud becomes much denser at
its center.
Sun and Planet Formation• The Solar Nebula:
– A rotating disk of dust and gas.– The center becomes the Sun.
Formation of Our Solar System
Sun and Planet Formation
Formation of Our Solar System
• 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
Sun and Planet Formation
The Growth of Objects
Formation of Our Solar System
– Planetesimals : formed as smaller particles collided and stuck together.
Asteroids
Pieces of Asteroids
Formation of Our Solar System
– 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.
Comets
Periodic Comets
Formation of Our Solar System
– 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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