AST101H5 Midterm: First Test Review Chapter 1-3
Document Summary
Ecliptic plane earth"s orbital pattern defines a flat plane (earth"s orbit pattern) Axis tilt 23 degrees perpendicular to ecliptic plane, pointing at north star/polaris. Earth takes a year to orbit sun and 24 hours to complete a rotation. Reason we don"t notice planets move so fast, is because they"re so far out. 1au 150, 000, 000 km distance between earth and sun. Edge of solar system approximately halfway to next star = 100,000au. Light needs significant amount of time to reach astronomical distances. Even extremely slow changes can cause huge changes over astronomical time. When we observe something now it happened in the past. Although they may seem grouped from earth, they may not be. In ast101, we used stars as fixed background only to detect movement. How far apart things are from each other. 60 minutes in a degree or 3600 seconds in a degree. Distance to the object (km) from earth.
