1. Stars
#20

2. Birth of a Solar System 5 Steps Nebula
rotating cloud of dust and gas expelled by a previous star that exploded
Shock wave causes part of nebula to collapse
Collapsed area begins to condense forming
A protoplanetary disk with a protostar at the center
Prostar continues to contract until fusion occurs, which creates a star
Rest of material begins to form planetesimals which then become planets.

3. Nebulas

4. Nebulas

5. Properties of a Star Color and Temp Brightness Hot to cold
Blue  White  Yellow  Orange  Red
Brightness
Measures distance
Apparent brightness
View from earth
Watts/meter squared
Absolute brightness
Actual brightness excluding distance
Watts/second

6. Hertzsprung-Russell Diagram
H-R diagram
Surface temp vs. luminosity
Can estimate distance
Main sequence
90% of stars
Runs from upper left to lower right of diagram

7. Other Stars Super giants Giant stars White dwarfs
Much brighter than most main sequence stars
Giant stars
Larger, cooler stars
White dwarfs
Small dense remains of a low or medium mass star

8. Life Cycle Nebula – 1st phase Protostar – 2nd phase Low-mass High-mass
Two possible sequences based on mass
Low-mass
Red giant  planetary nebula  white dwarf
High-mass
Red supergiant  Supernova  neutron star
Black hole

9. Geologic Time Earth forms Atmosphere forms Rise of life
Fossil Record indicates that single celled life first emerged 3.5 billion years ago
Cretaceous-Tertiary (K-T) extinction
65.5 million years ago
Dinosaurs extinct
Permian extinction
million years ago
Largest extinction of all
90-95% of marine species became extinct
Ice age
ended about 11,000 years ago

10. Universe is Expanding 1st Expanding universe 2nd Background Radiation
Distance between galaxies is increasing
Red Shift
Wavelength shifts to red as galaxies move further away, shift to blue as they get closer.
2nd Background Radiation
Microwaves left over from big bang

11. Words of Wisdom