Our Solar System and Its Origin

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Slide 1

Our Solar System and Its Origin

How was the Solar System Formed?

A viable theory for the formation of the solar system must be

based on physical principles (conservation of energy, momentum, the law of gravity, the law of motions, etc.),

able to explain all (at least most) the observable facts with reasonable accuracy, and

able to explain other planetary systems.

How do we go about finding the answers?

Observe: looking for clues

Guess: come up with some explanations

Test it: see if our guess explains everything (or most of it)

Try again: if it doesn’t quite work, go back to step 2.

Slide 2

What does the solar system look like from far away?

Sun, a star, at the center…

Inner Planets (Mercury, Venus, Earth, Mars) ~ 1 AU

They are all rocky planets…

Asteroid Belt, ~ 3 AU

Outer Planets (Jupiter, Saturn, Neptune, Uranus), ~ 5-40 AU

They are all gaseous planets

Pluto: odd ball planet, more like a comet…

Keiper Belt ~ 30 to 50 AU

Oort Cloud ~ 50,000 AU

Where comets come from…

NASA Figure

Cool link about solar system:

http://liftoff.msfc.nasa.gov/academy/space/solarsystem/solarsystemjava.html

Slide 3

Clues - The Orbits of the Planets

All the planets orbit the Sun in the same direction

The rotation axes of most of the planets and the Sun are roughly aligned with the rotation axes of their orbits.

Orientation of Venus, Uranus, and Pluto’s spin axes are not similar to that of the Sun and other planets.

Slide 4

What does the solar system looks like close up?

GOTO e-textbook, Chapter 6, Section 2….

Read the brief descriptions of the solar system objects…

Slide 5

Summary - What do the inner planets look like?

They are all…

rocky and small!

No or few moons

No rings

Slide 6

Summary - The Jovian Planets

They are all…

gaseous and BIG!

Rings

Many moons

Slide 7

Quantitative Planetary Facts

Slide 8

Terrestrial and Jovian Planets

Why?

Slide 9

The Kuiper Belt and the Oort Cloud

Kuiper Belt

A large body of small objects orbiting (the short period comets) the Sun in a radial zone extending outward from the orbit of Neptune (30 AU) to about 50 AU. Pluto maybe the biggest of the Kuiper Belt object.