6. The Milky Way
It is the name of our Galaxy.
It has spiral shape.
It contains one trillion stars.
Sun is one of the star in Milky way and
orbits the galaxy's core every 225 million
years.
7. THE UNIVERSE
The Universe contains billions of galaxies
with each galaxy containing billions of
stars.
Universe is always evolving. Everything
that exits in the universe is not permenant.
New stars are being born while existing
stars will eventually die.
8. Origin of The Universe
Two Models proposed
Steady State Theory- the universe has
always existed as it is now
Oscillation Model- universe expands
and contracts repeatedly over time
9. Edwin Hubble
• discovered :
1. galaxies are moving away
from us & each other
2. relationship between
distance to a galaxy & its
speed
10. Hubble’s law
Farther away galaxy is faster it is moving away from us
Doppler Shift- Light changes as it moves toward or away
form an object.
Starlight moving toward Earth shifts to blue-violet end of
spectrum
Starlight moving away from Earth shifts to red end of
spectrum
11. Big Bang Theory
Universe began 13.7 billion years ago with
a huge explosion that caused expansion
everywhere at the same time.
Hubble shows over 1,500 galaxies at a
distance more than 10 Billion light yrs
away showing a young universe
Whether the universe will continue to
expand or begin to contract is unknown.
12. Video
http://www.youtube.com/watch?v=PV0ACIykxQI
Editor's Notes
The universe is also constantly expanding in all directions. It is getting bigger all the time!