ASTRONOMY
PART II
I.
Types of Planets
A. Terrestrial – rocky & or icy
 Mars, Mercury, Earth etc.
B. Jovian – Gas giants

Jupiter, Saturn, Neptune, Uranus
II.
Other solar system object
A. asteroids – subplanetary objects concentrated between Mars and Jupiter
B. meteors - interplanetary material that may fall to earth as a meteorite
C. Comets – made up of rock an frozen gases
 Very eccentric orbits – close to one
 Tail always points away from the sun
 Examples – Haley’s, Hale –Bopp, Schmacher – Levy
III.
The Big Bang
A. Theory on how the universe began
B. Occurred more than 4.5x109 years ago
C. Evidence
1. Doppler shift
a. use colors of the spectrum to show the universe is expanding
b. ROYGBIV
c. light straight ahead appear as above
d. light moving away from you is shifted to the red
 light moving toward you is shifted to the blue
 this is a normal spectral alignment, the line represent the normal spread of
color
R
O
Y
G
B
I
V
2. Red shift – wavelength of light are shifted to the red end of the spectrum
R
O
Y
G
B
I
V
3. Blue Shift - wavelength of light are shifted to the blue end of the spectrum
R
O
Y
G
B
I
V
IV.
Life Cycle of a Star
A. Energy – from nuclear fusion (2 hydrogen atoms join together{fuse}some mass is
destroyed and energy is created. E=mc2
B. When matter runs low energy generating process covert to fission  less efficient
C. Luminosity and temperature diagrams ( H-R diagrams)
D. The Life of a Star
 The star begins as a c loud of gas in space.
 Due to gravity of every atom in the gas, the cloud will contract.
 As it contracts, it heats up.
 When the heat gets intense enough, atom will begin the process of fusion.
 The star is born and will continue to fuse its atoms until it runs out of fuel. At this
point the star can go on two different paths depending on the size of the star:
If the star is 7x or sun or smaller(low mass If the star is 7x or sun or larger(high mass)



Swell up to a red giant
Shrink to a white dwarf
Slowly cool and die black
dwarf





Swell up to a red giant
Shrink collapse and explode as a
supernova
Dies as a rapidly spinning core
Or better yet...
A black hole!
Star Trail Circumpolar Stars
As the Earth turns once a day, the stars appear to move across the sky in large arcs with
the North Star at the middle of the arc. If a camera was left open for several hours, the
stars will create streaks in the picture forming a bulls-eye around the North Star. The stars
that make a full circle without going below the horizon are called circumpolar stars and
are part of circumpolar constellations. These stars are visible all night, every night of
the year. In NY the Big Dipper is one of a few such circumpolar constellations.