Download No Slide Title

The Solar System
Section 2
Section 2: The Inner and Outer Planets
Preview
• Key Terms
• Bellringer
• The Inner Planets
• The Gas Giants
• Beyond the Gas Giants
The Solar System
Section 2
Key Terms
〉 How are the inner planets similar to one another?
〉 What are gas giants?
〉 What type of bodies lie beyond the gas giants?
The Solar System
Section 2
Bellringer
Based on what you have learned, as well as previous knowledge,
answer the following questions.
1. Our solar system consists of the sun and eight planets.
Make a list of at least six of the planets in our solar system.
2. Do you think that all of the planets in our solar system have the
same composition?
If not, describe some of the possible differences.
3. Scientists have sent many probes to explore and study Mars.
What similarities does Mars share with Earth? What are some
differences?
The Solar System
Section 2
The Inner Planets
〉 How are the inner planets similar to one another?
〉 The terrestrial planets are relatively small and have
solid, rocky surfaces.
• terrestrial planet: one of the highly dense planets
nearest to the sun
– The terrestrial planets are: Mercury, Venus, Earth,
and Mars.
The Solar System
The Inner Planets
Section 2
The Solar System
Section 2
Visual Concept: Astronomical Unit (AU)
Click the button below to watch the Visual Concept.
The Solar System
Section 2
Visual Concept: Day, Rotation, Period of
Rotation
Click the button below to watch the Visual Concept.
The Solar System
Section 2
Visual Concept: Year, Revolution,
Period of Revolution
Click the button below to watch the Visual Concept.
The Solar System
Section 2
The Inner Planets, continued
• Mercury has extreme temperatures.
– Mercury is the closest planet to the sun. One year there is
only 88 days on Earth.
– The side of Mercury facing the sun can reach 720 K. The
side facing away from the sun is only 103 K.
– Mercury is covered by craters.
The Solar System
Section 2
The Inner Planets, continued
• Thick clouds on Venus cause a greenhouse effect.
– Venus has a thick atmosphere containing large amounts of
sulfuric acid.
– The atmospheric pressure on Venus is 90 times that of
Earth.
– A runaway greenhouse effect keeps the surface temperature
above 700 K.
The Solar System
Section 2
The Inner Planets, continued
• Earth has ideal conditions for living creatures.
– Earth is the only planet known to harbor life.
• hydrosphere: the portion of Earth that is water
• The atmosphere protects Earth from radiation.
– Earth’s atmosphere is 78% nitrogen, 21% oxygen, and 1%
carbon dioxide and other gases.
– The atmosphere protects Earth from harmful radiation and
high-energy particles emitted by the sun.
The Solar System
Section 2
The Inner Planets, continued
• Many missions have explored the planet Mars.
• Mars has many extreme landforms.
– The Martian volcano Olympus Mons is the largest
mountain in the solar system.
– The surface of Mars is red from large amounts of
iron oxide in the soil.
The Solar System
Section 2
The Inner Planets, continued
• An asteroid belt lies beyond the orbit of Mars.
– The dwarf planet Ceres is in the asteroid belt.
• asteroid: a small, rocky object that orbits the sun;
most asteroids are located in a band between the
orbits of Mars and Jupiter
• dwarf planet: a celestial body that orbits the sun, is
round because of its own gravity, but has not cleared
its orbital path
The Solar System
Section 2
The Gas Giants
〉 What are gas giants?
〉 The outer planets are much larger than the inner
planets and have thick, gaseous atmospheres, many
satellites, and rings.
• gas giant: a planet that has a deep, massive
atmosphere
– The gas giants are: Jupiter, Saturn, Uranus, and
Neptune.
The Solar System
The Gas Giants
Section 2
The Solar System
Section 2
The Gas Giants, continued
• All the gas giants have rings and satellites.
• Jupiter is the largest planet in the solar system.
– Jupiter is big enough to hold 1300 Earths.
– Jupiter rotates once around its axis in less than 10
hours.
– Jupiter’s atmosphere has swirling clouds of
hydrogen, helium, methane, and ammonia.
– Jupiter has more than 60 satellites.
The Solar System
Section 2
The Gas Giants, continued
• Saturn has the most extensive ring system.
– Saturn is 95 times the mass of the Earth and takes
over 29 y to orbit the sun. It rotates in 10.7 h.
– Saturn’s rings are narrow bands of tiny particles of
dust, rock, and ice.
– Saturn has more than 40 satellites.
• Saturn may still be forming.
– Saturn radiates three times more energy than it
receives from the sun.
The Solar System
Section 2
The Gas Giants, continued
• Uranus and Neptune are blue gas giants.
– They hold thick, gaseous atmospheres composed of
hydrogen, helium, and methane.
– The methane gives both planets a bluish color.
– Uranus is 14 Earth masses, and it takes about 84 y
to orbit the sun at its distance of 19 AU.
– Neptune is 17 Earth masses, and takes
approximately 164 y to orbit the sun at a distance
of 30 AU.
The Solar System
Section 2
Visual Concept: Inner and Outer Planets
Click the button below to watch the Visual Concept.
The Solar System
Section 2
Visual Concept: Comparing Prograde
and Retrograde Motions
Click the button below to watch the Visual Concept.
The Solar System
Section 2
Beyond the Gas Giants
〉 What type of bodies lie beyond the gas giants?
〉 Beyond the gas giants are numerous small bodies
composed of ice and rock.
• Not all large objects in the solar system are planets.
– The scientific definition of planet was decided upon
in 2006 by the International Astronomical Union.
– Pluto, formerly considered a planet, was reclassified
as a dwarf planet.
The Solar System
Section 2
Beyond the Gas Giants, continued
• There are many objects beyond Neptune.
– Beyond Neptune lies the Kuiper Belt.
– The Kuiper Belt contains many small bodies of ice
and rock.
– Scientists think that these bodies are the remnants
of the material that formed the solar system.
– At least two dwarf planets, Pluto and Eris, can be
found in the Kuiper Belt.