How big is our galaxy?
Units of Measure
- light years
- AU’s
How do we measure the distance to objects in space?
closer than 500 light years - Paralax Method
- trigonometry
- d = 3.23/p
How do we determine the distance to very distant objects?
- average luminosity of pulsating stars - cepheid variables
The Sun & Earth
distance = 1 AU - optimum distance for liquid water
fusion reaction
Magnetic field
Solar weather
Sun Spots and Solar Flares
solar winds
The magnetic field
why is having a magnetic field a good thing
Solar Radiation
Why is it colder in the winter and warmer in summer?
aphelion & perihelion
tilt of the axis
insolation
Seasons
tilt and insolation
duration of daylight