Our Solar System Unit Interactive Notes
Our Solar System Unit Interactive Notes Table of Contents....45
Illustrations: The Eight Planets….46
Notes: The Eight Planets….47
Illustrations: Rotation and Revolution….48
Notes: Rotation and Revolution….49
Illustrations: Earth, the Moon, and the Sun….50
Notes: Earth, the Moon, and the Sun….51
Illustrations: Phases of the Moon….52
Notes: Phases of the Moon….53
Illustrations: NASA Apollo Program….54
Notes: NASA Apollo Program….55
Illustrations: Four Famous Astronomers….56
Notes: Four Famous Astronomers….57
The Eight Planets
Our solar system is made up of eight planets that orbit, or travel in
a circular path, around the sun. The sun is the center of our solar system
and each planet is located a certain distance from the sun. These plants
located in order based on their position from the sun are Mercury,
Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. We can
place them in order if we remember this sentence: My (Mercury) very
(Venus) energetic (Earth) mother (Mars) just (Jupiter) served (Saturn) us
(Uranus) nachos (Neptune).
These planets can be sorted into two groups, a terrestrial planet or
a gas giant. A terrestrial planet is one that is made up of rocks and
metals and is located close to the sun. They have few moons or no
moons at all. A gas giant is one that is made up of gases and is located
farther from the sun. Gas Giants have multiple moons and have rings
orbiting around them. Mercury, Venus, Earth, and Mars are terrestrial
planets. Jupiter, Saturn, Uranus, and Neptune are gas giants.
Each of these planets have different characteristics that make them
unique. One of these characteristics is their size. The largest of these
planets is Jupiter. Following Jupiter in size is Saturn, Uranus, Neptune,
Earth, Venus, and Mars. The smallest planet in our solar system is
Mercury. In fact, due to its small size and craters it looks like our moon.
Rotation and Revolution
Rotation is when the earth spins on its axis. When our side of the
earth rotates toward the sun, we have daytime. When we rotate away
from the sun, we have nighttime. It takes 24 hours for the earth to spin
on its axis one time.
Revolution is when the earth travels around the sun. It causes
the seasons, because the earth is tilted on its axis. As the earth travels
around the sun, the hemisphere that is tilted toward the sun has summer,
and the hemisphere that is tilted away from the sun has winter. It takes
365 days for the earth to travel around the sun 1 time.
Earth, the Moon, and the Sun
Earth is one of 8 planets that revolve around the sun and make up
the solar system. The Earth, the 3rd planet from the sun, is one of the 4
terrestrial planets. It is 4 times the size of the moon. It is a geologically
active planet with a surface that is constantly changing. Unlike the other
3 terrestrial planets, it has large amounts of life-supporting water and an
oxygen-rich atmosphere. The Earth’s protective atmosphere blocks out
most of the sun’s damaging rays.
Our moon is a rocky satellite, having about 1/4 the diameter of the
earth and 1/80 its mass. It also has extreme temperatures because there
is almost no atmosphere, no water, and no life.
The sun is an average-sized yellow star, about 110 times the
diameter of the earth. More than a million Earths could fit inside of it.
The sun is approximately 4.6 billion years old. Its surface is not solid. It
is made of gases like helium and hydrogen.
Phases of the Moon
The different shapes of the moon are called its phases. The
moon’s phases are caused by its position relative to the Earth and sun.
When we see a new moon, the moon is between the sun and the Earth
and you can’t see the lighted side of the moon. As we see more and
more of the moon we say it is waxing. With a waxing crescent moon,
the lighted side of the moon begins to show. When we see the first
quarter moon, the moon is a quarter of the way around the earth. A
waxing gibbous moon is almost full. With a full moon, the moon is
now halfway around the earth. You can see all of its lighted side. As the
moon continues to move around the earth, we see less and less of it, and
we say it is waning. We see a waning gibbous, a last quarter moon,
and a waning crescent. When the moon is between the Earth and the
sun again, we have another new moon and the cycle starts all over again.
NASA Apollo Program
Much of our knowledge of the moon comes from the investigations
of astronauts who have traveled there by way of the NASA Apollo
program. The NASA Apollo program of the 1960’s and 1970’s had several
goals: to make America the first country to land people on the moon, to
make America first in space exploration, to carry out scientific exploration
of the moon, and to develop man’s ability to work in the lunar
environment. Beginning in 1967 and ending in 1972, the NASA Apollo
program put 12 Americans on the moon.
The NASA Apollo 11 mission is one of the most well-known missions.
July of 1969 was the first manned lunar landing. When Neil Armstrong
stepped on the moon, he spoke these famous words: “That’s one small
step for man, one giant leap for mankind.” He and Buzz Aldrin were on
the moon’s surface for 2 hours and 31 minutes, collecting soil and rocks
and setting up science experiments. They left an American flag and a
plaque which said: “Here men from planet earth first set foot upon the
moon. July 1969 AD. We came in peace for all mankind.”
Four Famous Astronomers
An astronomer is someone who studies stars, planets, and space.
Our understanding of the solar system has changed over the years
because of different astronomers.
Aristotle (384-322 BC), from Greece, believed that the universe
centered around the Earth. This is called the geocentric theory. He
also discovered that the Earth was round and not flat when he watched
an eclipse of the moon and noticed that the Earth’s shadow on the moon
was curved.
Ptolemy (100-170 AD), from Egypt, also believed that the Earth
was the center of the universe (geocentric theory) and he also believed
that the earth was fixed and did not rotate.
Nicolas Copernicus (1473-1543 AD) was a Polish astronomer
who used math to figure out that the sun, not the Earth, was the center
of the solar system. This is known as the heliocentric theory. Many
people did not accept his theory.
Galileo Galilei (1564-1642) was an Italian astronomer who also
believed in the heliocentric theory. He was one of the first people to
use a telescope to observe planets and stars. With the telescope he
observed that Venus had phases just like Earth’s moon. He believed that
if the Earth were the center of the universe, we wouldn’t be able to see all
of Venus’s phases, so the sun must be the center.