Transcript Solar System PPT

Part One: Earth’s Place in
Space
This PowerPoint Presentation is from the Gaston County
Schools Secondary Science Website
• Earth rotates and revolves around the Sun, even
though it appears as though the Sun is moving! The
Sun is the force which keeps our solar system
together!
• Rotation – spinning of Earth on its axis (23
degrees), which occurs once every 24 hours.
• Earth moves around the Sun in a regular, curved
path called an orbit
• It takes about one year for Earth’s revolution
around the Sun
• We have leap years because our planet rotates exactly 365.24
times in one revolution. So we have leap years to make up for
that extra time!
• SEASONS occur due to Earth’s tilted axis and its
revolution around the Sun
TERMS TO KNOW….
• Rotation: When an object spins on its
axis (Think of a basketball spinning on a
finger)
• Revolution: When an object travels
around another object
• Orbit: The path that an object takes as it
revolves around another
A Day on Earth
The Seasons
• Change of seasons is a result of the tilt of the
Earth’s rotation axis (23 degree slant) with
respect to the plane of the ecliptic.
• Sun, moon, planets run along the ecliptic
(their paths)
• We experience summer, when we tilt towards
the sun.
• We experience winter, when we tilt away from
the sun.
The Seasons
Motion of the Moon
• Moon shines not by its own light but by reflected light
of Sun
• Moon revolves around the Earth
• Moon’s period of rotation = 27.3 days
• Period of revolution =27.3 days
• The Tides of the oceans are caused by the moon’s
pull on Earth
• The Moon’s changing shapes are known as phases
The Moon
Phases of the Moon (THE LUNAR
CYCLE)
Caused by the position of the
Earth, the Moon, and the Sun
new to full = waxing
full to new = waning
…and the phases…with Oreos!
Copy this into your notes
Eclipses
• One celestial object hidden by other or in the
shadow of another
• Solar eclipse: sun hidden by the Moon, as
Moon is between the Sun and Earth and the
Moon’s shadow falls on Earth
• Lunar eclipse: Earth is between the Moon
and the Sun and Earth’s shadow falls on the
Moon
• Most spectacular because moon and sun
appear to be the same size from earth
Solar Eclipses
• Umbra – region of total shadow
• Penumbra – region of partial shadow
• Totality lasts only a few minutes!
Solar
Lunar Eclipses
Moon moves
into earth’s
shadow…
Part One Review
1. What is the gravitational force that keeps our
solar system together? Explain.
2. How are rotation, revolution, and orbit different?
3. Explain how the seasons occur. When do we
experience summer and winter?
4. Explain why we have leap years.
5. How do we see the moon? List the phases of
the moon beginning with a new moon.
6. What causes the tides of the earth?
7. What are eclipses? Identify and describe the
differences between the two we discussed.
PART TWO: OUR SOLAR
SYSTEM
THE MILKY WAY
Our Solar System
• Earth orbits the Sun as the solar
system revolves within the Milky
Way, which is among billions of
galaxies that make up the universe
• Introduction to the Solar System –
VIDEO CLIP
Our Solar System is filled with
eight major planets, the Sun, and
other objects that orbit the Sun
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Mercury
Venus
Earth
Mars
Jupiter
Saturn
Uranus
Neptune
Pluto (not classified as a
planet any longer!)
THE SUN
The Sun
• The Sun is one of one-hundred
billion stars in our galaxy.
• It is the brightest object in the sky.
• The sun is by far the largest object
in our solar system.
• It is the sun’s gravitational pull
which holds our planets in order.
Inner Planets
• Solid, with minerals similar to those
on Earth
• Include Mercury, Venus, Earth, and
Mars
MERCURY
Mercury
• Mercury is the closest planet to the sun
and is the smallest planet now that
Pluto is deemed a “dwarf planet”
• There is little to no atmosphere,
resulting in extremes of temperature;
can reach 430 degrees Celsius during
the day and drop to –180 degrees
Celsius at night!
Mercury Facts
VENUS
Venus
• Venus is the third brightest object in the sky.
• It is the second closest planet from the sun and
is the sixth largest.
• Heavy cloud layer; clouds trap solar energy,
making the planet extremely hot ~ 470 degrees
Celsius!
• Considered to be Earth’s twin because it’s
similar in size.
Venus Facts
EARTH
Earth
• Earth is the third planet from the sun
and is the fifth largest.
• This planet is the densest major body in
our solar system.
• The Earth’s atmosphere protects its life
from the harmful rays of the sun.
• Life on Earth is possible because of
water availability and the stability of
temperatures.
Earth Facts
MARS
Mars
• Mars is the fourth planet from the sun
and is the seventh largest.
• The first space craft to visit Mars was
the Mariner 4 in 1965.
• Has seasons and polar ice caps; may
have water shaping its surface
• Red due to rocks containing iron oxide
• Two small moons
Exploring Mars
Asteroid Belt
• Separates the inner (rocky) and outer (gas
giants with lots of moons and rings) planets
• It is located between the planets of Uranus
and Neptune
• Pieces of rock made of minerals similar to
those that formed the rocky planets and
moon
• Jupiter’s huge gravitational force might have
prevented a small planet from forming in the
area of the asteroid belt
JUPITER
Jupiter
• Jupiter is the fifth planet from the
sun and is by far the largest planet.
• Jupiter is the fourth brightest object
in the sky.
• 28 moons; Giant Red Spot is a
giant storm on the planet’s surface
Jupiter Facts
SATURN
Saturn
• Saturn is the sixth planet from the sun
and is the second largest.
• Saturn is the least dense of all the
planets because it is mostly composed
of gases (hydrogen and helium)
• Has 30 moons; several broad rings of
ice and dust.
Saturn Facts
URANUS
Uranus
• Uranus is the seventh planet from
the sun and the third largest.
• Uranus has only been visited one
time, by the Voyager 2 in 1986.
• Axis makes the planet spin nearly
sideways; has rings and 21 moons
Exploring Uranus
NEPTUNE
Neptune
• Neptune is the eighth planet from
the sun and is the fourth largest.
• Neptune has 8 moons.
• Atmosphere is composed of
hydrogen, helium, and methane
(make planet blue)
Neptune Facts
PLUTO
Pluto
• Pluto is the farthest object from
the sun and is by far the
smallest.
• Pluto is the only dwarf planet
that has not been visited by a
space craft.
Exploring Pluto
All planets move in same plane
except Pluto
Is Pluto a planet?
• Orbit too
weird
• Too small
• Today Pluto
may not be
classified as
a planet.
Comets
• Large body of frozen ice and rock that travels
toward the center of the solar system
• As a comet approaches the Sun, radiation
vaporizes some of the material; solar winds blow
vaporized gas and dust away from the comet,
forming what appears from Earth as a bright,
glowing tail
Meteorites
• Fragments of space material that land
on Earth’s surface
• Pieces may be iron, rock, or both
• Age (4.5 billion years) provides a clue to
the Solar System’s age
Stars
• About 5000 stars visible with naked eye
• About 3500 of them from the northern hemisphere
• Stars that appear to be close are grouped together
into constellations
• Officially 88 constellations
• Names range from
• mythological (Perseus, Cassiopeia)
• technical (Air Pump, Compass)
Lives of Stars
• A star has a life that depends on its size
• Stars begin their lives as huge clouds of gas
and dust
• Force of gravity causes dust and gases to
move closer together
• Temperatures within the cloud begin to rise
• Star is formed when this cloud gets so dense
and hot that the atoms within it merge (fusion)
Galaxies
• Group of stars, gas, and dust held together
by gravity
• Earth is in a spiral galaxy called the Milky Way
• 100 billion galaxies might exist ~ all these
galaxies with all their stars make up the
UNIVERSE!