Unit 2 Lesson 1 What Objects Are Part of the Solar
System?
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Unit 2 Lesson 1 What Objects Are Part of the Solar System?
Florida Benchmarks
• SC.5.E.5.2 Recognize the major common
characteristics of all planets and compare/contrast
the properties of inner and outer planets.
• SC.5.E.5.3 Distinguish among the following
objects of the Solar System—Sun, planets, moon,
asteroids, comets—and identify Earth’s position in
it.
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Unit 2 Lesson 1 What Objects Are Part of the Solar System?
The Solar System
• Earth, other planets, and moons are part of a
solar system.
• Solar systems are made up of a star and the
planets and other space objects that revolve
around it.
• Planets are large, round bodies that revolve
around a star.
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Unit 2 Lesson 1 What Objects Are Part of the Solar System?
The Solar System
• There are eight planets in our solar system.
• All planets rotate, or spin, around an axis.
• An axis is an imaginary line that goes through the
center of the planet.
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Unit 2 Lesson 1 What Objects Are Part of the Solar System?
The Solar System
• Earth rotates once on its axis every 24 hours.
• That is the length of one day on Earth.
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Unit 2 Lesson 1 What Objects Are Part of the Solar System?
The Solar System
• In our solar system, the planets orbit the sun.
• The orbits are oval-shaped, or elliptical.
• The planets in our solar system are very far from
one another.
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Unit 2 Lesson 1 What Objects Are Part of the Solar System?
The Solar System
• Moons are small, natural objects that revolve
around other objects.
• Earth has one moon that revolves around Earth
about every 27 days.
• Some planets have more than one moon.
• Mercury and Venus do not have any moons.
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Unit 2 Lesson 1 What Objects Are Part of the Solar System?
The Inner Planets
• The four inner planets are Mercury, Venus, Earth,
and Mars.
• The inner planets are very dense and rocky. They
also have thin atmospheres and small diameters.
• The inner planets have large solid cores and few
moons.
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Unit 2 Lesson 1 What Objects Are Part of the Solar System?
Mercury
• Mercury is the smallest planet in our solar system.
• The surface of Mercury is full of craters.
• Mercury is the closest planet to the sun.
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Unit 2 Lesson 1 What Objects Are Part of the Solar System?
Venus
• Temperatures on Venus are high enough to melt
lead.
• Thick clouds on Venus are made up mostly of
carbon dioxide.
• There are more than 1,000 volcanoes on Venus’s
surface.
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Unit 2 Lesson 1 What Objects Are Part of the Solar System?
Earth
• Earth has an atmosphere made of mostly
nitrogen, oxygen, and carbon dioxide.
• Earth is the only planet known to have abundant
liquid water.
• Water helps keep Earth at temperatures that allow
life.
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Unit 2 Lesson 1 What Objects Are Part of the Solar System?
Mars
• Mars is known as the “Red Planet” because of its
red, rocky surface.
• Giant dust storms cover the entire planet.
• There are also huge volcanoes on Mars.
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Unit 2 Lesson 1 What Objects Are Part of the Solar System?
The Outer Planets
• The planets farthest from the sun are Jupiter,
Saturn, Uranus, and Neptune.
• The outer planets are known as gas giants. They
are huge and made up mostly of gases.
• All of the outer planets have many moons and
ring systems.
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Unit 2 Lesson 1 What Objects Are Part of the Solar System?
Jupiter
• Jupiter is the largest planet in the solar system.
• Massive, spinning storms, such as the Great Red
Spot, are visible on Jupiter.
• Jupiter has rings, but they are faint.
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Unit 2 Lesson 1 What Objects Are Part of the Solar System?
Saturn
• Saturn is the second-largest planet in the solar
system.
• Saturn has thousands of rings around it. The rings
are made of ice and chunks of rock.
• Saturn has many moons and large storms, like
Jupiter.
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Unit 2 Lesson 1 What Objects Are Part of the Solar System?
Uranus
• The axis of Uranus is tilted so far that it appears
to rotate on its side.
• Heated gases deep inside Uranus bubble and
burst onto the surface, causing bright clouds to
form.
• Uranus has at least 13 faint rings.
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Unit 2 Lesson 1 What Objects Are Part of the Solar System?
Neptune
• Winds on Neptune can reach 2,000 km/hr.
• The Great Dark Spot on Neptune is a storm that
travels around the planet.
• Neptune has nine rings around it.
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Unit 2 Lesson 1 What Objects Are Part of the Solar System?
Compare Inner and Outer Planets
• Size, surface features, distance from the sun,
temperatures, number of moons, and diameter
make the inner and outer planets different.
• The period of revolution of a planet is the time it
takes for a planet to revolve around the sun.
• The period of rotation of a planet is the time it
takes to rotate on its axis.
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Unit 2 Lesson 1 What Objects Are Part of the Solar System?
The Flying Objects
Moons
• Moons in our solar system differ from each other.
• Some moons may contain a lot of ice.
• Some moons have many volcanoes.
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Unit 2 Lesson 1 What Objects Are Part of the Solar System?
Dwarf Planets
• Pluto was once classified as a planet. Now it is
classified as a dwarf planet.
• Dwarf planets are nearly round bodies whose
orbits cross the orbits of other bodies.
• Dwarf planets are very far away and hard to
study.
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Unit 2 Lesson 1 What Objects Are Part of the Solar System?
Asteroids
• Asteroids are rock and iron objects that orbit the
sun.
• Millions of asteroids are found in the wide region
between Mars and Jupiter known as the asteroid
belt.
• Asteroids range in size from as small as a city
block to the size of an ocean.
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Unit 2 Lesson 1 What Objects Are Part of the Solar System?
Meteoroids, Meteors, and Meteorites
• Meteoroids are pieces of rock that break off
asteroids and travel through space.
• Meteor is a term used to describe the streak of
light caused when a meteoroid burns up in Earth’s
atmosphere.
• If a meteoroid reaches Earth’s surface, it is called
a meteorite.
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Unit 2 Lesson 1 What Objects Are Part of the Solar System?
Comets
• A chunk of frozen gases, rock, ice, and dust is
known as a comet.
• As comets pass close to the sun, part of the
frozen surface breaks away and turns into gases
and dust.
• These particles reflect sunlight and look like long
tails that always point away from the sun.
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Unit 2 Lesson 1 What Objects Are Part of the Solar System?
Space Watch
• Objects such as comets, meteoroids, and
asteroids can hit the surface of other bodies in the
solar system.
• The impact, or hit, from space objects creates
impact craters.
• Scientists keep track of the size, position, and
motion of space objects near Earth using
telescopes.
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