Download Space and the Solar System

Space and the Solar
System
• Stars are enormous balls of
superheated gases.
• The sun is a star. It is the major
source of energy for the Earth
• The solar system consists of the
sun and eight planets—Mercury,
Venus, Earth, Mars, Jupiter,
Saturn, Uranus, and Neptune
Major Ideas Continued
• The Earth spins or rotates on its
axis. This spinning causes us to have
day and night.
• The Earth is tilted on its axis as it
revolves around the sun. This
explains why the seasons of the year
change from spring and summer to
fall and winter.
• The moon orbits the Earth. The sun’s
light reflects off the moon, causing
us to see the moon at night.
Stars
• Stars are enormous balls of
superheated gases. The nearest star
to Earth, after the sun, is 40 trillion
kilometers away.
• Stars are formed by clouds of gases
and dust in space.
• These gases and dust come together
and begin to spin. This action
eventually forms a star.
The Sun
• The sun is one of millions of stars in the
galaxy known as the Milky Way.
• The sun is the source of most of our energy
on Earth and the rest of the solar system.
• The sun is the source of our heat and
allows living things on our planet to
survive.
• The sun’s energy id the main influence on
Earth’s climate and weather.
• The sun is the largest object in our solar
system.
• Cooler areas on the sun’s surface are
known as sunspots.
The Planets
• Planets are objects of rock,
metal, ice and gas that circle
the sun.
• The largest planet is Jupiter—
ten times the width of Earth.
• In general, the farther away a
planet is from the sun, the
cooler it is.
Diagrams of the Solar
System
• Diagrams and models of the solar
system are not usually made to
scale.
• Scale diagrams showing how far
apart the planets are from each
other would not fit on a page in a
book.
• The same is true of the size of the
planets. The sun’s width is 10 times
that of Jupiter. If drawings were to
scale, the entire solar system would
not fit on one page.
The Movement of the
Earth and Moon
• Earth moves in two different
ways at the same time: it
rotates and it revolves.
Earth’s Rotation
• The Earth rotates, or spins, on
its axis.
• This rotation takes 24 hours,
causing day and night on Earth.
Earth’s Revolution
• The Earth revolves,or circles, around
the sun in just over 365 days or one
year.
• The Earth tilts on its axis as it
revolves.
• This tilt causes the sun’s rays to hit
the Earth more directly or indirectly
in the different hemispheres at
different times of the year, causing
our seasons.
Movement of the Moon
• The moon is a satellite of the Earth.
• The moon takes 29¼ days to orbit
the Earth.
• The moon is about one fourth the
size of Earth
• Because the moon is smaller than
Earth, its gravitational pull is weaker.
• Something with the same mass will
weigh less on the moon than on
Earth.
More on the Movement
of the Moon
• The pull of the moon’s gravity is the
main cause of the rising and fall of
ocean tides.
• The moon does not produce its own
light. It appears bright because it
reflects light from the sun.
• The amount of the moon that is
reflected each night changes every
29¼ days
Moon Phases
• The moon changes that we see on
Earth are known as the moon’s
phases.
• The moon appears to change as the
moon orbits Earth. When both the
Earth and sun are on the same side
of the moon, the moon is lit up. When
the moon is between the Earth and
the sun, the moon appears totally
dark.
• Look on page 134 at the principal
phases of the moon.
Characteristics of the
Moon
• The moon is made of hard rock with
craters.
• There is no water, air, soil or living things.
• There is no wind.
• There is no atmosphere and no weather
like we have on Earth.
• Meteors hit the moon without slowing down
due to the absence of any atmosphere.
• Temperatures on the moon range from 100°
C to -173°C.