Transcript Planetary Orbits and Rotation

Warm Up ???
Planets travel around the Sun along paths called
orbits. What shape do you believe a planetary orbit
consists of?
2. Does the Earth’s distance from the sun ever change as
it follows its orbital path around the sun?
3. What causes seasons on earth (Winter and
Summer)?
1.
Planetary Orbits
 The planets do not orbit the sun in a circular pattern.
 Johannes Keplar (German mathematician, 1600’s)
discovered that the planets orbit the sun in the shape
of an ellipse.
Earth
Sun
Foci (#2)
 The Sun is not at the center of this ellipse but is
slightly offset to one side. It is one of two foci.
Planetary Orbits
Earth’s Tilt and Rotation
 Earth’ axis is tilted 23.5
degrees.
 Thus, at times in the year
the northern and
southern hemispheres
are tilted toward the sun.
 The hemisphere that is
tilted toward the sun
receives more hours and
more direct sunlight
during the day.
Season’s, Solstices, and Equinoxes
 The solstice is the day
when the sun reaches it’s
greatest distance North or
South of the equator.
 Summer Solstice is longest
day of year
 Winter solstice shortest
day of year
 Earth is closest to the sun
during the winter solstices
for the northern
hemisphere.
Season’s, Solstices, and Equinoxes
 An equinox occurs when
the Sun is directly above
Earth’s equator.
 Most of the year the sun
is north or south of the
equator but two times a
year it is directly above it
 These times are called
fall and spring
Equinoxes.
Tilt and Temperature
 After performing the tilt
and temperature lab
answer the following
question to check your
understanding.
 Why do more direct rays
of sun (closest to 90 ̊)
create higher
temperatures or more
heat?