Aristotle
lived about
2,300 years
ago. He
came up
with this
model of
the solar
system.
About 500
years ago, a
man named
Copernicus
came up
with this
new model
of the solar
system.
What do you
notice about
it?
Take a look and compare – what do
you notice?
Ancient people liked the idea that the Earth
was at the center of the solar system.
They also thought that the orbits of the
planets were perfect circles. (They aren’t.)
But when people made observations, some
things didn’t make sense. They often tried
to make their theories fit what they
wanted to believe.

The Earth tilts in the same direction no
matter where it is compared to the sun.
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The Vernal Equinox occurs today, at 1:36 in the
afternoon.
What does that mean?

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It is usually
warmer in the
middle latitudes
– near the
equator.
This model
shows part of
the reason.
t

Here’s
another
reason that
it’s warmer
near the
equator.
The energy from the
sun has to go
through a larger
layer of the
atmosphere.
u
The Phases of the
Moon
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New
Waxing crescent
First quarter
Waxing gibbous
Full
Waning gibbous
Last quarter
Waning crescent
waxing = growing
waning = shrinking
gibbous = “humpbacked”
(bigger than half)
Full moon rises at sunset & sets at sunrise
New moon rises & sets with the Sun
1st quarter rises at noon
3rd quarter rises at midnight
If you’re on the moon…
…it’s the
Earth that
appears to
have
phases!

Distances are not to scale, and we have idealized the
illustration by fixing the Earth in space relative to the Sun.
In reality, the Earth will be in motion around its orbit as
the Moon moves around the Earth.
http://csep10.phys.utk.edu/astr161/lect
/time/lunar_anim.html
Lunar Eclipse
A lunar eclipse occurs when the moon passes through the shadow of the
earth.
A lunar eclipse can last up to an hour and a half.
During a lunar eclipse the moon may turn a reddish color.
It is not dangerous at all to look at a lunar eclipse because the moon does
not make its own light.
Animation by Stephen Gray using photos
Sputnik
History changed on
October 4, 1957, when
the Soviet Union
successfully launched
Sputnik I.
The world's first artificial satellite was about the
size of a basketball, weighed only 183 pounds,
and took about 98 minutes to orbit the Earth on
its elliptical path.
A month later, Sputnik II was
launched, carrying a much heavier
payload, including a dog named
Laika.
The Sputnik launch also led
directly to the creation of
National Aeronautics and
Space Administration.
In 1961, President John F.
Kennedy gave a speech. He said
that the U.S. should work quickly
and meet a goal. The goal was to
send people to the Moon and
back.
The U.S. did meet the goal. And it
only took eight years. One day in
July, Apollo 11 launched towards
the Moon. It had three astronauts
on it. They were Neil Armstrong,
Edwin (Buzz) Aldrin and Michael
Collins.
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On July 20,
1969, Neil
Armstrong
put his left
foot on the
rocky
Moon.
It was the
first human
footprint on
the Moon.
They had
taken TV
cameras
with them.
The Lunar Lander
That’s one small step…
The diameter of the sun is about
100 times larger than the Earth.
The sun is big, but the largest stars
are 700 times larger than our sun.
Solar Eclipse
A Solar Eclipse occurs
when the moon goes in
front of the sun and blocks
most of the sun's light
from the earth.
During a total eclipse all
you can see from earth is a
ring of light around the
moon which is part of the
sun the moon did not
cover.

It is dangerous to look at a solar eclipse directly, even if you have sun
glasses or smoked glass. It is better to view solar eclipses through a pin
hole projector.
Solar Eclipse
Diagram c/o Wikimedia Commons