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Chapter 19
I. The Sun, Earth and Moon
A. __________is our closest star
B. Everything ______________ around the Sun
C. Planets and distant stars are visible in the _________________
D. Earth is part of ______________________
E. _________________________ holds the solar system together
1. We usually think of gravity as the ____________________ that pulls us to
the Earth.
2. True definition of gravity is the attractive force between ____________.
3. The more _________ an object has the ________ its gravitational pull.
a. The _______ has more mass than any object in the solar system
b. everything in solar system orbits around Sun
c. tides are caused by the __________ gravitational pull on the
Water on the Earth
F. The Moon
1. Moon __________ orbit the Sun directly
a. orbits the ________
i. due to this the moon has ___________
2. How was the moon formed?
a. Earth collided by large body & part of the Earth _______________
i. ejected material _______________ together
ii. moon began to orbit the ___________
3. Evidence?
a. _____________________of the moon is the same as the Earth’s
4. Phases of the moon
a. phases of the moon are ____________ by Earth’s shadow
b. also see book page 634
5. Eclipses
a. occur when Earth, Moon and Sun line up…….SOLAR ECLIPSE
b. _________________- eclipse
Formation of the Solar System
Nebular Model of Space Formation
A. according to this theory the solar system is about _________________ years old.
B. See transparency A
II. During this process small celestial bodies also formed
A. _________- long tails and icy centers
1. orbits around Sun usually very long
B. ___________- made from different elements
C. ____________- sometimes strike the Earth
Chapter 20
I. The Life and Death of Stars
A.
What are stars?
1. Stars are huge spheres of ___________ that emit _______ and other radiation
2. they are driven by _______________________________ reactions
a. may take ______________ of years for energy to make its way through
B. Why are some stars brighter than others?
1. depends on star’s _______________, __________ and _______________ from earth
C. How do we get information about stars
1. ____________________
a. the wavelengths ( including those out of the visible spectrum) tell us all about
the _______________________ of the star
i. stars color tell us its temperature
*______________ are the hottest
*______________ are the coolest
ii. spectral lines tell us what kinds of _____________ the stars are made of
D. The fate of stars
1. Remember the sun formed from a cloud of _______ and ____________
2. It now has a balance of _____________ and ________ forces
3. AS __________ slows, the pressure in the core will drop and contract this will cause
the outer layers to expand
a. the sun will become a ______________________
4. After about ______________________years the core will run out of helium and will
contract further which will cause outer layers to __________________.
a. the sun will then become a __________________
i. about the size of ___________
5. Supergiants- very massive star
1. evolve ___________ than smaller stars
2. core is _________
a. iron _________________ fuse together to make heavier element
b. put more energy in than is given out……..______________ reaction
c. star will explode……____________________
d.. after this explosion either a ____________ star (very massive, but only
few kilometers large) thimble full of a neutron star has more mass than_____ million times
the earth
e. or a ____________ will form (matter so massive and compressed not
even light can escape it)
6. ____________________ shows how stars evolve
1. compares the __________________to the _____________________
II. Origin of the Universe
A. Universe- everything __________________ that exists in space and time
B. We see the universe now as it was in the________
1. Recall we get information about the stars from ________
2. It takes _______ for light to travel the enormous distances it needs to get to us
3. By the time this light reaches us, the star may _______________ be there
C. Most of the universe is __________________
D. What do we know about the Universe?
1. The universe is _______________________
2. Doppler effect…..weather or train
a. _________________……object coming closer to us
b. _________________……moving away
E. Future of the Universe
1. Future is uncertain
a. 3 possibilities….depends on the total amount of matter in the universe
i.
____________________________________…not enough
mass, gravitational forces too weak to stop expansion
ii. _________________________________________……just right
amount of mass…will slow but never stop completely
iii. _________________________________________________…..
more mass than gravity will overcome this expansion and the
universe will start to contract
*eventually this contraction could collapse into a single point
in space (__________________)……maybe the universe will
end or maybe start all over with another big bang
2. Universe contains _______________________….scientist don’t know how
much or how to detect
3. Scientists are using ______________ to build better models
a. Time travel