Transcript Beyond our Sol. System

Beyond our Solar System
Solar System - consists of 1 or 2 stars, planets, satellites, asteroids, meteors, and
comets
Galaxy – consists of about 1 billion stars and possibly their solar systems
Local Group – our Local Group contains our Milky Way and about 28 other
galaxies
Cluster – a group of 100 galaxies
Supercluster – a group of clusters
Universe – there is an estimated 50 billion galaxies in the Universe.
No one really knows where the Universe ends or if it does end. We do
not even know what shape it has. Does it extend outward in every
direction?
Mrs. Degl
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The Nebular Hypothesis – the theory on how our Solar System formed.
Our Sun formed in this nebula. It was quite an explosion (nuclear fusion) that sent a
lot of extra material propelling into space. All of this left over material that did not
get used up in the formation of the Sun was still spinning around in space.
Eventually it all combined together because of gravity. The inner planets formed
next, and kept spinning. The inner planets are made of the heavier elements. The
left over light material kept propelling into space and eventually these light materials
came together because of gravity and formed the outer gas planets. That is why the
inner planets are made of more dense materials than the outer planets. Only light
gasses could make it so far out into space.
Sun
Inner Planets
Outer Planets
Mrs. Degl
That’s the order!!
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There are 4 types of Galaxies
1. Spiral
(Our Milky Way Galaxy is a rotating Spiral Galaxy)
2. Barred
3. Elliptical
(These are the most common)
4. Irregular
(No shape)
These are usually very young
galaxies with very young stars.
Mrs. Degl
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The Earth is part of the Milky Way Galaxy. The next
nearest is the Andromeda Galaxy.
Our solar
system is
here
Above is a side view of the Milky Way Galaxy. It is a rotating
spiral galaxy. We live in one arm of the galaxy. The ball in
the middle is called the Central Bulge. That is where most of
the other star systems are located. That is what makes it much
brighter.
Mrs. Degl
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Above is a top view of the Milky Way Galaxy.
Since the galaxy rotates, the Sun "orbits" the center, taking 200
million years to complete one circuit.
Mrs. Degl
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This is the Orion Nebula, where other solar systems appear to be forming.
Orion is located in the same arm of our galaxy (Milky Way). It takes light 1500
years to reach Earth from the Orion Nebula. Maybe the solar systems are
already formed?
Mrs. Degl
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This is the Trapezium nebula. Here, you see solar systems
forming.
Mrs. Degl
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The Big Bang Theory – theory on how the entire Universe
formed. Estimated between 10 and 20 billion years ago.
The Universe was once confined to a point of matter that was very massive,
very dense, and very hot. This is before space and time existed.
It is believed that there was an explosion so big that all of the matter in the
Universe today was created in that explosion. Just like after any explosion,
matter was thrown out in all directions. The same matter is still traveling
outward today. It is believed that the matter closer to the center of the
explosion came together to form stars and planets first. It seems like the
distant parts of space are still forming.
We can now prove that the Universe is expanding at an accelerating rate. That
means that the speed of expansion is increasing all of the time. Stars and other
objects that are further away from us are traveling faster than we are. We have
evidence that the Universe is expanding. It is the Red Shift part of the Doppler
Effect. Everything in space is moving away and we can tell by the increasing
wavelengths of light that they give off.
Mrs. Degl
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This is the deepest view of space ever seen. It was taken by the Hubble
Telescope and it tells us a lot about what is out there in the Universe. And this
picture is only facing one small section of space. There are so many stars and
galaxies. Who knows where the end is. And if the Universe is constantly
expanding, is there an end?
Mrs. Degl
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What happened after Earth formed?
It took quite a while for the
planet to cool down.
The inner Earth is still molten
today.
After most of the planet’s
surface was solid rock, the inner
Earth was still outgassing
(giving off water vapor, carbon
dioxide, methane, nitrogen etc..)
There was virtually no oxygen. The atmosphere was
mostly Methane.
Steam from the cooling planet eventually condensed to form the primitive oceans.
Bacteria were the first life forms on Earth, and it started in the oceans. Plants began to
evolve because they breath carbon dioxide, not oxygen. These plants then began to
release oxygen into the atmosphere and water. This caused the oxygen content to
increase over time. It took about 4 billion years after Earth formed before there were
any organisms that breathed oxygen.
The Earth is 4.6 billion years old.
Mrs. Degl
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