Class Notes (1,100,000)
CA (650,000)
UTM (30,000)
AST (200)
AST101H5 (100)
Lecture 6

AST101H5 Lecture Notes - Lecture 6: Solar System, Double Planet, Headon


Department
Astronomy
Course Code
AST101H5
Professor
John Lester
Lecture
6

This preview shows page 1. to view the full 4 pages of the document.
Chapter 6: Formation of Our Solar
System
HOW DID THE SOLAR SYSTEM FORM?
Challenge
oSolar system formed 4.5 billion years ago
oWe are here now and cannot go back in time
Approach
oWe use the systematic properties of the solar system
oWe observe clues now
SYSTEMATIC PROPERTIES OF ORBITS
All large objects orbit counterclockwise when viewed from above the
north pole of the earth and sun
All large objects have nearly circular orbits
oJust slightly elliptical
Most larger objects spin in the same direction as their orbit=
counterclockwise
Most orbits nearly align with sun's equator= plane of the solar system
Most of the larger moons share these traits:
oCounterclockwise orbits
oCounterclockwise spin
oAligned above their planet's equator
SYSTEMATIC PHYSICAL TRENDS
Terrestrial planets are all made of rocks and metal and are close to the
sun
Jovian planets are all largely made of gas and *uids and are far from
the sun
Dwarf planets are all ice and rock and are very far from the sun
Asteroids have families and locations
Comets are "dirty snowballs" from two regions of the outer solar
system
DEVIATIONS FROM THE TRENDS
Venus and Uranus spin opposite (clockwise) to their orbit direction
Comets have very elliptical orbits that do not align with the sun's
equator
Most moons are much smaller than their planet, but Earth's moon is
similar in size to earth (also Charon and Pluto)
Theories of the solar system must be *exible enough to handle these
deviations
You're Reading a Preview

Unlock to view full version