Download The Sun and Stars

The Sun, Stars, Galaxies, and
Universes
Earth Science
Mr. Ward
Basic Facts about Stars
• Stars,planets, asteroids, meteorites, and
comets were all formed in a Nebula (Gas
Cloud)
• Stars are fixed points/positions in
space- they don't move only planets
move!!! In fact, planets often eclipse
stars… See pictures
Day 1
Stars are made of Hydrogen and
Helium
• T
Gravity Nuclear Fusion
• Stars 'Burn' Hydrogen
to produce Helium
• This is known as the
process of Nuclear
Fusion or Hydrogen
Fusion
• This is one of 2
forces acting on
stars
• The other force is
gravity
The Life Cycle of Stars
• Because of these 2
forces: Gravity &
Nuclear Fusion Both act on a star in
opposite ways
• A star unlike people
starts very big and
then becomes smaller
overtime due to the
'fuel' from Nuclear
Fusion running out!
Red Giant
Main
Sequence
Black
Hole
The Hertzsprung-Russell (H-R)
Diagram
• Based on this
diagram stars are
tracked by 4 qualities:
• Color and Size
• Luminosity
• Magnitude
• Temperature
The Sun is a Main Sequence Star
• 90% of the stars in our solar system are main
sequence stars or halfway to becoming a
"blackhole“
• Although Stars contain the most mass in space,
space is mostly DARK MATTER
We study stars with different
instruments such as:
• The Hubble Space
Telescope
• Reflecting Telescope
• Refracting Telescope
• Radio Telescope
Final facts about Stars
• Once a star becomes a
Black hole… the gravity is
so strong that light can’t
escape it
• Light travels at a speed of
300,000 km per second
• Stars can “burnout” but
because they are so far
away it would take
millions of years before
we stop seeing the light
Galaxies and Universes
• There are over a
100 billion stars in
a Galaxy
• There are over a
hundred billion
galaxies in a
universe
2 Theories on How the Universe
was formed
• Big Bang Theory
– Over 45 Billion years ago
an explosion happened in
space creating the planets,
stars, etc. (inside a nebula)
• Steady State Theory
– The Universe has
never changed and
has been the same
since the beginning of
time
– Because it was found
that the universe is
expanding… this
theory has become
obsolete
3 Types of Galaxies
• Spiral
– Normal  No bar
– Barred A bar
between the arms
• Elliptical- An oval
shaped galaxy
• Irregular- Has no
definite shape
• Galaxies are
continuing to expand
because of Big Bang
Our Galaxy: The Milky Way
• It is a barred spiral galaxy
• It has a flat disk shape
• The Sun is located on
Orion’s Arm
• It is 100, 000 light years
in size from edge to edge
• A light year is the amount
of time it takes for light to
travel in a year
Copy and Answer these “Check
for Understanding” Questions
1. Where is the Sun located
in the Milky Way Galaxy?
2. How many types of
Galaxies are there?
Name them.
3. What are the 2 forces at
work on stars?
4. What is a light year?
5. What percentage of stars
are main sequence stars?
6. How fast does light
travel?
7. Explain why some stars
become black holes.
8. Which theory is currently
believed about how the
universe was formed?
9. Explain why sometimes
you may see a star and
then sometimes you can’t.
10. What type of galaxy is the
Milky Way galaxy?