What is the Big Bang
Theory?
Balloon Demonstration…
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1. Partially inflate a balloon. Twist
the opening and hold it shut.
2. Draw and label four squares A,B,C,
& D on the balloon. Measure the
distance between the squares.
Record the data.
3. Inflate the balloon to its fullest
capacity. Repeat your
measurements.
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Balloon Demonstration…
What happened to the distances
between the dots as you inflated the
balloon?
Did some of the dots move farther
apart than others? Why?
Suppose the balloon represents the
universe. How does this activity
show what is happening to the
universe and to the galaxies in it?
What’s in an universe?
A universe contains
the Earth and everything on it.
 It also contains everything in
the solar system.
 All stars, of which the Sun is
one, are part of the universe.
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Speed of Light
Light travels at 300,000 km/s.
 If you traveled at the speed of light
it would take 10,000,000,000
(billion) years just to travel the
distance astronomers see with their
telescopes.
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Astronomers Think…
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They believe the universe was created
10-15 billion years ago.
Billions of years ago, the Universe was
very small. A huge explosion, referred to
by astronomers as the Big Bang, sent
the entire universe flying out at incredible
speeds.
Astronomers Think…
Eventually matter cooled and condensed
into galaxies and stars.
 How did the big bang form galaxies?
Hydrogen and Helium are left in space
after the Big Bang.
 Planets formed.
 That the universe is still expanding.
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How did the big bang form
galaxies?
 About
200 Million years later,
Hydrogen and Helium joined to
form stars.
 Stars were drawn together by
gravity to form a family of stars
called- GALAXIES
What is the name of our galaxy?
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In 1927, the Belgian priest Georges
Lemaître was the first to propose that
the universe began with the explosion
Edwin Hubble found experimental
evidence to help justify Lemaître's
theory. He found that distant galaxies
in every direction are going away
from us with speeds proportional to
their distance.
Astronomers Think…
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Astronomers have discovered the
outward motion of the galaxies have only
slowed down a little since Big Bang.
The universe may continue to get Bigger
and Bigger forever!
Let’s review…
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Who created the Big Bang Theory?
In 1927, the Belgian priest Georges
Lemaître was the first to propose that the
universe began with the explosion.
Explain the Big Bang Theory.
A huge explosion, referred to by astronomers
as the Big Bang, sent the entire universe
flying out at incredible speeds. The universe is
still expanding.