Transcript earth in space ppt

EARTH IN SPACE
DAY AND NIGHT
• The Earth completes
one rotation on its axis
every 24 hours. The
rotation of the Earth on
its axis is responsible
for day and night.
• The Earth rotates
counterclockwise. The
counterclockwise
rotation is what makes
the sun appear to rise
in the east and set in
the west.
SEASONS
• The Earth completes
one counterclockwise
revolution around the
sun every 365 ¼ days.
• The revolution of the
Earth around the Sun,
along with a tilt of 23.5
degrees on its axis, is
responsible for seasons
on Earth.
SEASONS
• Shadows are
shortest in the
summertime and
longest in the
wintertime. The
appearance of the
shorter shadows is
due to the sun being
more directly
overhead in the
summertime.
THE MOON
• The apparent shape of
the Moon in our sky
depends on how much
of the Moon’s
illuminated side is
visible from Earth.
• As the moon orbits
(revolves around) the
Earth, it goes through a
predictable cycle of
changes called phases.
THE MOON
• The Moon’s cycle is divided into eight
equal parts:
THE MOON
• During the waxing
moon, the illuminated
portion is continually
growing bigger (right
side is lit).
• During the waning
moon, the illuminated
portion is continually
growing smaller (left
side is lit).
ECLIPSES
• An eclipse can occur
when the Sun, Earth,
and Moon align
perfectly
• A solar eclipse can
occur only during a
new moon.
• A lunar eclipse can
occur only during a
full moon
ECLIPSES
• SOLAR ECLIPSE: Occurs during a new
moon, when the Moon comes between the
Sun and Earth and casts a shadow on part
of the Earth.
ECLIPSES
• LUNAR ECLIPSE: Occurs during a full
moon, when the Earth comes between the
Sun and Moon and casts a shadow on the
Moon.
THE SUN AS AN ENERGY
SOURCE
• Radiation is the direct transfer
of energy by electromagnetic
waves
• Solar radiation is energy from
the Sun. It is a major source of
energy on Earth.
• The farther away an energy
source, the greater its energy
output must be to produce the
same effect as a closer source.
• Earth and its atmosphere
absorb and reflect the Sun’s
radiant energy; the absorbed
energy heats the planet and its
atmosphere.
SUNSPOTS AND SPACE
WEATHER
• A sunspot is a region of the
Sun’s surface that is relatively
cooler and darker than its
surroundings
• Sunspots vary in size,
locations, and number
• Changes about the locations of
sunspots reveal information
about the rotation of the Sun
on its axis
• Space weather is the result of
solar disturbances such as
sunspots, which affect people
and equipment in space and
on Earth.
THE MOON- IMPACT CRATERS
• Impact craters are bowl-shaped holes in solid, rocky
surfaces that are formed when large meteoroids,
asteroids, or comets smash into the surface of a
terrestrial planet, asteroid, or moon.
• The character of an impact crater depends on the size of
the impacting object and the speed which it strikes the
surface
• Rays of ejected materials
radiate outward from an impact
crater in all directions
• Many craters on Earth have been
eroded by wind and water and
destroyed by tectonics and volcanism.
SURFACE GRAVITY
• Gravitation is the force that
attracts objects to each other.
• Surface gravity holds us to the
Earth’s surface.
• Surface gravity depends on the
mass and radius of the planet.
• Mass is the amount of matter
in an object.
• Weight is the measure of the
force of gravity on an object.
• An object with more mass has
a stronger gravitational force
pulling on it and therefore
weighs more.
GRAVITY AND ORBITAL
MOTION
• Any two objects, from the largest galaxies to the
smallest particles, attract each other with a force
called gravity.
• Gravity keeps planets in orbit around the Sun
and governs all motion in the solar system
• Most objects in the solar system are in regular
and predictable motion
• Unbalanced forces, including gravity, can
change the speed and/or direction of an object’s
motion.
GRAVITY AND ORBITAL
MOTION
GRAVITY AND TIDES
• Tides are the periodic rise and fall of the sea
level and other bodies of water
• The gravitational attraction between Moon and
Earth (and Sun and Earth) contributes to the
formation of tides
• Normally two high and two low tides occur each
day
• The time at which high and low tides occur
changes by about 50 minutes each day due to
the Moon’s orbit around Earth.
GRAVITY AND TIDES
ASTEROIDS, COMETS, AND
METEOROIDS
• Asteroids are rocky and metallic (nickel/iron)
objects that orbit the Sun, but are too small to be
considered planets.
• The majority of asteroids move between Jupiter
and Mars in an area known as the “asteroid
belt.”
• There are over 200 asteroids that regularly cross
the path of Earth.
• These “Earth crossers” are usually about 1 km in
diameter.
ASTEROIDS, COMETS, AND
METEOROIDS
• Comets are relatively small solar system
bodies made of ice, rock, and dust; each is
in an independent elliptical orbit around
the sun, often outside of the solar system.
• Ancient Greek scientists referred to
comets as “hairy stars.”
• A comet is made of three parts: head, tail,
and core / nucleus.
ASTEROIDS, COMETS, AND
METEOROIDS
• Meteoroids are space matter too small to
be called asteroids or comets. (They do
not orbit the sun.)
• Meteors are streaks of light produced
when meteoroids are illuminated as they
fall into the Earth’s atmosphere (shooting
stars)
ASTEROIDS, COMETS, AND
METEOROIDS
• Meteorites are the actual rock pieces that hit the
surface of the Earth.
• Meteorites that hit the Earth’s surface are
moving at about 45 miles per second (162,000
miles per hour).
• Estimates suggest that more than 20 million
meteors enter the Earth’s atmosphere daily –
most break down before they get to the surface.
ASTEROIDS, COMETS, AND
METEOROIDS
INNER PLANETS
OUTER PLANETS