Transcript The Formation of Stars

The Formation of
Stars
The Emptiness of Space?
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It was once thought
that the space
between stars in our
galaxy was empty.
What we now know is
much different.
The Emptiness of Space?
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The space between
stars is filled with gas,
dust, solar wind from
other stars, and more.
Discovery
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It took scientists
hundreds of years to
finally understand.
At that same time
theories were
developed around the
formation of stars and
planetary systems
such as our own.
Let’s Pause…
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And read page 474.
Theory of Star Formation – You be
the Scientist
Please turn to p.476 in your texts.
 This activity will give you a small insight
into what scientific theorizing is all about.
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The Solar Nebula Theory
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This theory best
explains how our sun
and planets formed.
The Solar Nebula Theory
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Scientist calculate our
sun to be about 5
billion years old.
Some of the oldest
rocks found on Earth
are about 3.5 billion.
This fits with the
theory.
A Cloud of Gas
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More than 5 billion
years ago our solar
system was nothing
more than a huge
cloud of swirling gas
and dust.
Gravity At Work
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Particles in this cloud
came together
because of the force
of gravity.
Gravity at Work
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Eventually
temperatures at the
center of the cloud
reached a point
where fusion
occurred.
Our sun was born.
Other Spheres Form
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In the accretion disc
around the new star,
other spheres began
to form.
These would become
the planets.
It’s Hot Near the Center
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The spheres near the
new star were subjected
to extreme radiation.
These inner planets did
not have enough gravity
to hang on to their thick
gaseous atmospheres
and they were literally
blown away, leaving
rocky spheres.
Things Start to Cool Down
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Slowly temperatures
began to cool.
Water began to
condense on Earth.
Eventually life would
form there.
Catastrophic Theory
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Another theory
suggests the planets
were created in
another way.
It states that the sun
collided with another
large body, most likely
another star.
Catastrophic Theory
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It was this collision
that provided the
matter to form the
other planets.
Evidence for the Solar Nebula
Theory
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Despite there being
competing theories,
there is strong
evidence to support
the Solar Nebula
Theory.
More Evidence
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Photos of accretion
discs around new
born stars strongly
suggest the Solar
Nebula Theory is
correct.
Other Planets Out There?
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Other solar systems
means the possibility
of other planets.
In fact we’ve found
some.
Quite a few in fact,
726 as of January,
2012.
Extra-Solar Planets
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What might these
new planets look like?
Is there life here?
At this point it is all
just speculation.
Extra Solar Planets
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The photo to the right
shows three extra
solar planets around
the star HR 8799.
Homework
Please finish reading section 14.3
 Answer question #1-5 and 7.
 Vocabulary
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 Inter-Stellar
Medium
 Solar Nebula Theory
 Extra-Solar Planets