Patterns in the Solar System Ch 23. Plane of the ecliptic All planets are within 3 o of a line Drawn outward from the Sun’s equator The path of the Sun.

Patterns in the Solar System

Ch 23

Plane of the ecliptic

All planets are within 3o of a lineDrawn outward from the Sun’s equator

The path of the Sun across our sky

Origin of the Solar System

• Nebular Theory• • A nebula is a cloud

of gas and/or dust in space.

• According to the nebular theory, the sun and planets formed from a rotating disk of dust and gases.

Two Groups of Planets

• Terrestrial Planets (land like)

Mercury, Venus, Earth and Mars

Inner planets, small, and rocky

• Jovian Planets (Jupiter-like)

Jupiter, Saturn, Uranus and Neptune

Outer planets, very large, mostly gaseous

Which planet is the most dense?

Which planet would you weigh the most on?

Which planet(s) have not orbited the Sun in your lifetime?

Which planet has the shortest day?

Laws of Planetary Motion

• Johannes Kepler (1571-1630)

• 1st Law – The path of each planet around the Sun is an ellipse, with the Sun at one focus. ( the other focus is symmetrically located at the opposite end of the ellipse)

Kepler’s 2nd Law

• Each planet revolves so that an imaginary line connecting it to the Sun sweeps over equal areas in equal time intervals.

Kepler’s 3rd Law

• The planet’s orbital period (time it takes to orbit the Sun) squared =

the distance from the Sun cubed

p2 = d3

Minor Members of the Solar System

• An asteroid is a small, rocky body whose diameter can range from a few hundred kilometers to less than a kilometer.

• Most asteroids lie between the orbits of Mars and Jupiter. They have orbital periods of three to six years.

Comets

• Comets – pieces of rocky and metallic materials held together by frozen gases

• Known as “dirty snowballs”

• They have very eccentric orbits. They travel in orbits that go to the far reaches of our solar system

Kuiper Belt and Oort Cloud

• Kuiper Belt – a narrow region out at the edges of the solar system

• Oort Cloud – a spherical shell at the outer edges of the solar system

Meteoroid, Meteors, Meteorites

• Meteoroids – small solid particle traveling through space

• Meteor – object falling though our atmosphere

• Meteorite – has survived the fall thru the atmos. , is found on the Earth’s surface