Download Solar nebula theory

Definition:
A gigantic cloud of dust and gas in
the universe that clumps together to
form stars and planets.
Example: The eagle
nebula.
Facts:
The gas is mostly the smallest atomshydrogen and helium. The dust is
extremely small particles too small to be
seen with the eye.
Gravity pulls the gas and dust together.
Nebula
Non-example:
The Milky Way galaxy which already has
gone beyond a cloud of gas and dust to
form a galaxy.
Definition:
An explanation that is supported by a
lot of evidence and which is widely
accepted by scientists and other people.
A theory can sum up a lot of
observations and is used to make
predictions.
Generally a theory is a working
hypothesis until new evidence comes
along. It is not a fact!
Ex: The theory of evolution keeps
changing as we learn new facts.
Theory
Examples:
Theory of Evolution
Theory of Plate Tectonics
String Theory of Gravity
Solar Nebula theory
A good theory can be used to predict
phenomena or behavior. The theory of
evolution is a poor predictor.
Definition:
A pulling force that draws things with
mass together.
Facts:
Gravity acts over extremely large
distances.
Gravity acts on the smallest of particles
(a molecule or bit of dust or atom) to
the largest of objects (a star, a galaxy
and the universe).
Gravity
Example:
Gravity pulls the Earth and Moon
towards each other and keeps the moon
in orbit around the Earth.
Gravity pulls the Earth and Sun
together and keeps the Earth in orbit
around the Sun.
Non-Example:
Gravity is not friction or a pushing
force.
First: The fusion rate
increases. This means,
hydrogen atoms fuse
together to become
helium until all of the
hydrogen is used up.
Some very low mass
stars never go beyond
this stage. They use up
their hydrogen and cool
and become like a
planet. They are called
Brown Dwarfs.
Second: In big enough
stars: the temperature
increases and more energy
is released.
Some low mass stars use
up all of their hydrogen ,
cool, and shrink. They
become White Dwarfs.
Third: Some
moderate mass stars
get brighter when
they run out of
hydrogen. The outer
shell expands and
cools. They become
Red Giants. Their
outer shell gets
blown away and
becomes a nebula
while the core
becomes a White
Dwarf.
Really massive stars end their lives by exploding as a
Supernovae. The core will then collapse and become
a black hole.
5 billion years ago:
75% hydrogen
25% helium
Today:
35% hydrogen
65% helium
5 billion years in the future:
0% hydrogen
100% helium
Earth’s temperature will be about 40 0F hotter. The oceans
will be gone.
The Sun’s outer core will expand and the Sun will become
a Red Giant.
Theory #1: The Earth will get engulfed by the Sun and
exist no more.
Theory #2: When the Sun first begins to shrink,
gravitational attraction between the Earth and Sun will
become less. Some scientists think the Earth may move
away from the Sun as gravity no longer holds them
together. If this happens, the Earth will be a cold, desolate,
barren rock in space.
• Title Page: Solar Nebula Theory
• Page 1: Explain what a scientific theory is and is not.
Use examples.
• Page 2: Describe a nebula.
• Page 3: Step 1: Draw a cloud of gas and dust (nebula).
Describe how this cloud begins to contract due to
gravity.
• Page 3: Draw a disk with a bulge at the middle.
Describe how this forms from the nebula.
• Page 4: Draw a star with matter surrounding it.
Describe how a star begins.
• Page 5: Draw a planetary system around the star.
Describe how the matter forms into planets.
• Page 6: Describe the life cycle of an ordinary star.