Theories of the Universe

							       Origin of the Universe
•All matter came together at a single point

•An enormous explosion occurred (“Big Bang”)
and the universe began expanding.

•Galaxies are moving away from each other
      Wavelengths of light




•Blue light has shorter wavelength
•Red light has a longer wavelength
       Red Shift and Blue Shift
• Star is moving away from Earth then
  the light wave is slightly expanded
  and shifts to red end of light
  spectrum
• Star is approaching Earth then light
  wave is pushed together and shifts to
  blue end of light spectrum.
Theories of the Universe
            Big Bang Theory
• The Universe began with a densely packed
  mass and exploded out.
• The Universe continues to expand.
• Evidence found in Red Shift.
Steady State
Theory
-The Steady State
Theory, developed in
1948, concluded the
Universe had no
beginning and no end.
-Steady State Theory
proposes that matter
is being continuously
created. This would
allow the density of
the universe to remain
constant as it expands.
        Open Universe Theory
• Such a universe will never end, but will
  eventually become very cold and dark because
  stars gradually lose all of their energy.
• Galaxies continue to expand because of lack of
  gravitational forces between them.
     Closed Universe Theory
the universe is closed if it is sufficiently
dense, and therefore possesses
enough gravitational force to stop or
reverse the expansion started by the
big bang
               Spiral Galaxies
• Spiral: They are in the shape of a flat disk with
  a bright central nucleus and spiral arms that
  extend out from the nucleus.
• The arms of a spiral galaxy have lots of gas and
  dust, and they are often areas where new
  stars are constantly forming.
             Elliptical Galaxies
• Elliptical galaxies have very little gas and dust.
  Since stars form from gas, little star formation
  occurs in elliptical galaxies. Most of their stars
  are old and red.
            Irregular Galaxies
• Irregular galaxies are usually found in groups
  or clusters, where collisions and near-misses
  between galaxies are common