Transcript Terrestrial planets

 Identify the basic characteristics of the inner planets
and outer planets.
 Compare the characteristics of the inner and outer
planets.
 Summarize the features which allow Earth to sustain
life.
 Explain why Pluto is different from the other eight
planets of Earth.
•
Terrestrial planets: dense
planets nearest to the sun;
also known as the inner
planets.
•
These planets consist mostly
of solid rock and metallic
cores.
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The number of moons per
planet varies from zero to
two.
•
The surfaces of inner planets
have bowl-shaped
depressions called impact
craters, which were caused
by collisions with other
objects.
Mercury, the planet nearest the Sun, is the
second smallest planet in our solar system.
It is only slightly larger than the Earth's
moon. The surface is covered with craters.
This tiny planet does not have any rings or
moons.
Evidence of
craters
 Orbital period = 88 days
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Rotational period = 59 days
 Large daily temperature
range…as high as 427°C
during the day, and as low as
–173°C at night.
 Second planet from the sun
with an orbital period of 225
days.
 Rotational period = 243
days.
 Venus and Earth are of
almost the same size, mass,
and density, but differ greatly
in other areas.
 Venus’s atmospheric
pressure is about 90 times
the pressure on Earth.
 Venus’s high concentration
of carbon dioxide (96%),
results in an average surface
temperature of 464°C,
compared to Earth’s 15°C
Missions to Venus
 Volcanoes and lava plains
are the most common
features. Maat Mons is
Venus’s highest volcano, at
an elevation of 3 km (about
10,000ft.)
 Instruments indicated that
the surface of Venus is
composed of basalt and
granite.
 Venus is covered by a thick
layer of clouds, mainly
composed of micron-sized
droplets of sulphuric acid and
other aerosols
 Earth is the third planet from the sun, with an orbital
period of 365 1/4 days and a rotational period of 1
day
 Geologic records indicate that Earth’s surface has
undergone many changes over the last 250 million
years.
 Earth’s unique atmosphere and distance from the
sun allow water to exist in a liquid state.
 Earth is the only known planet that has the proper
combination of water, temperature, and oxygen to
support life.
Mars is 50% farther from the sun than Earth, and the 4th
planet in our solar system.
Orbital period
= 687 days
Rotational period =24
hours and 37 minutes
Mars seasons are much like
Earth’s because its axis tilts at
nearly the same angle that
Earth does
The pressure and temperature of Mars’s
atmosphere are too low for liquid water to
exist on the surface of Mars.
•Most of the water is trapped in frozen form within polar icecaps, as
permanent frost, or in liquid form just below the surface.
•Mars even has clouds, but they are very thin.
•Surface features on Mars are characteristic of erosion by water, and
evidence that liquid water did exist in the past.
•It is very cold on Mars, with the average temperature ranging from 140° C to 20° C.
Most asteroids can be found in the Asteroid Belt: an area of numerous asteroids
located between Mars and Jupiter. Asteroids are rocky and metallic objects that orbit
the Sun, but are too small to be considered planets. Asteroids range in size from
Ceres, which has a diameter of about 1000 km, down to the size of pebbles.
 Gas giants: planets with a deep massive atmosphere,
made up of mostly of hydrogen and helium gases and
separated from the inner planets by a ring of debris
called the asteroid belt.
 Pluto is not a gas giant and may not have formed in the
same way as other planets.
 Gas giants are larger and more massive than terrestrial
planets, but much less dense, and are mainly
composed of rock and metal.
 All four gas giants have ring systems made of dust and
icy debris that orbit the planets.
Gas giants: planets with a
deep massive
atmosphere, made up of
mostly of hydrogen and
helium gases and
separated from the
inner planets by a ring
of debris called the
asteroid belt.
•Gas giants are larger and more massive than terrestrial
planets, with 15-300 times the mass, and 4-11 times the
diameter.
•Not believed to have solid surfaces.
Jupiter, the fifth planet from the Sun, is the largest planet in our solar system.
Jupiter is so big that over 1,000 planets the size of Earth could fit into it.
It has over 60 moons and 2 rings. Can life exist on Jupiter's moon, Europa?
The “Great Red Spot”
Is actually a huge
Storm system!
Here are a few of Jupiter’s moons
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Hydrogen and helium make
up 92% of Jupiter, so its
composition is much like
the sun
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Believed to be a failed star,
lacking the mass to become
a small one
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Most massive planet in
solar system.
 Rotational period = 9 h and
50 min
 Takes 12 years to orbit the
sun! (Orbital period)
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Gravity almost 2.5 times
that of the Earth.
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The red spot is a
huge storm that has
been continuously
going on Jupiter for
over 400
years! Winds inside
this storm reach
speeds of about 338
mph. With a
diameter of 15,400
miles, this storm is
almost twice the size
of the entire Earth.
Period of Rotation = 778.3 days
Period of Revolution = 11.86 years
Saturn, the sixth planet from the Sun, is the second largest planet in our solar
system. It is often called the ringed planet because many rings of dust and
rocks surround it. Saturn also has over 31 moons.
Saturn with some of
its moons
Some of Saturn’s rings
Titan is a moon of Saturn that may have some conditions necessary for
life! The picture on the right shows an artist’s drawing of how Titan might
have looked when the Cassini-Huygen’s probe dropped into its
atmosphere in Dec., 2004.
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2nd largest planet in
solar system.
Rotational period = 10
h and 30 min, so 1
“day” on Saturn is a
little over 10 hours
long!
Orbital period = 29.5
years, so it takes 29
years to orbit the sun.
Almost 10 times larger
than Earth.
Most visible rings of
any planet, which you
probably already knew!
Period of Rotation = 1,427 days
Period of Revolution = 29.46 years
Uranus is a very unusual planet because it sits on its side with north and
south poles sticking out the sides. It rotates around this axis, making it look
like a ball rolling around in a circle around the Sun.
some of Uranus’s moons
Black rings
 3rd largest planet in the
solar system
 Mass is 14.5 times that of
Earth
 Orbital period = 84 years
 Rotational period = 17 hrs
 Uranus has 24 moons and
at least 11 thin rings
Neptune, the eighth planet from the Sun, is a very cold place.
Occasionally, Pluto crosses Neptune’s orbit.
Its bluish color comes from its atmosphere of methane gas.
Tiny Dark Moon
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Rotational period =
16hrs.
It takes 165 years to
revolve around the
sun! (Rotational
period)
Has a mass 17 times
greater than Earth
Has 13 moons
Pluto, once the ninth planet from the Sun, is the smallest planet in our solar system if
you want to consider it a planet. Some scientists believe that Pluto once was one of
Neptune’s moons, and that it pulled out away from Neptune and made its own orbit.
Clearest view to date
Of Pluto and Charon
 Orbits the sun in an
unusually elongated and
tilted ellipse.
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2/3rds the size of our moon.
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Has one moon, Charon.
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Pluto is composed of frozen
methane, rock, and ice
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The average temperature on
Pluto is –235°C, which is so
cold that oxygen and
nitrogen in its atmosphere is
frozen solid.
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Only planet not visited by a
spacecraft.
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Pluto takes 248 years to
make one orbit around the
sun!
New Horizons Pluto Kuiper Belt Flyby
In recent years, scientists
have discovered hundreds
of objects in our solar
system beyond Neptune’s
orbit in the Kuiper Belt
Some are more than half
of Pluto’s size, so scientists
think Pluto should no longer
be classified as a planet
The mission is expected to arrive
at Pluto sometime in 2015.
Kuiper belt: a region of
the solar system just
beyond the orbit of
Neptune, which contains
small bodies made mostly
of ice
Comets: a mixture of ices (both water and frozen gases) and dust, which for
some reason didn't get incorporated into planets when the solar system was formed.
This makes them very interesting as samples of the early history of the solar system.
Comets have
elliptical orbits.
Comet Halley in 1910
When we see a comet, we
are seeing the tail of the comet
as comes close to the Sun.