SECTION D: CHAPTER 3
THE SOLAR SYSTEM
Grade 4: SCIENCE
STUDY GUIDE

 

Vocabulary

asteroid   A small rocky object that moves around the sun
axis   An imaginary line which runs through both poles of a planet
comet   A small mass of dust and ice that orbits the sun in a long, oval-shaped path
gas giants   Planets are large spheres made up mostly of gases - for example, Jupiter, Saturn, Uranus, and Neptune
inner planets   The planets closest to the sun; Mercury, Venus, Earth, and Mars
orbit  
The path that an object such as a plane makes as it revolves around a second planet
outer planets   The planets farthest from the sun; Jupiter, Saturn, Uranus, Neptune, and Pluto
phase   One of the different shapes the moon seems to have as it orbits around Earth
planet   A large object that moves around a star
revolution   The movement of any object in an orbit, such as Earth moving around the sun
rotation   The motion of a planet or other object as it turns on its axis
satellite   An object that moves around another object in space; the moon is a satellite of Earth
solar system   A group of objects in space that move around a central star
space probe   An uncrewed space vehicle that carries cameras, instruments, and other research tools
star   A huge, burning sphere of gases; for example, the sun
telescope   A device people use to observe distant objects with their eyes

 


CRITICAL THINKING

1. Why are the earth and moon both classified as satellites?

Both the Earth and moon orbit an object in space.

2. What are two ways that the Earth moves?

Earth revolves around the sun and rotates on its axis.

3. What causes seasons?

Seasons occur due to the uneven tilt of Earth's axis and Earth's movement around the sun.

4. Why do we see phases of the moon?

The moon reflects light from the sun. As the moon moves through its orbit around Earth, different amounts of its lighted surface can be seen from Earth.

5. What is the sun?

The sun is a star, which is a burning sphere of gases.

6. What is the source of almost all energy in our solar system?

Our sun is the source of almost all energy in our solar system.

7. How does a planet's distance from the sun affect its orbit speed?

The closer a planet is to the sun, the faster it moves in its orbit.

8. What can be thought of as the dividing line between the inner planets and the outer planets?

The asteroid belt is between the inner and outer planets.

9. Compare and contrast Venus and Earth?

Both Venus and earth are inner planets in our solar system. Both are about the same size. They differ in that there is very little water on Venus and the atmosphere of Venus is very dense. Venus rotates on its axis in a direction opposite that of Earth's rotation.

10. What are two types of telescopes and which one would be better to use during severe weather - a radio telescope or an optical telescope? Why?

The two types of telescopes are an optical and radio telescope. A radio telescope would be better during severe weather because it is able to collect data in weather conditions that might affect an optical telescope.

11. How area an optical and radio telescope different?

An optical telescope collects and focuses light, a radio telescope collects and focuses radio waves.

12. What kind of work do astronauts on a crewed space mission do?

People go into space to explore and study how conditions in space affect living and nonliving things.

13. What are the advantages of sending crewed missions instead of probes into space? The disadvantages?

Crewed missions have the advantage of providing firsthand observations by people. Such missions are expensive, as life support systems must be provided. the can also be dangerous.

14. What are some advantages of sending a space probe instead of crewed missions to gather data?

Space probes can operate over long distances and time. A crewed mission is limited because it needs food, water, and an oxygen supply.

Corona

The “crown.” The sun’s upper atmosphere. Like the chromosphere, it is visible only during a solar eclipse

Solar Flares

Sudden blasts of burning gas. They shoot millions of miles into space and release a powerful burst of energy.

Core

The super-hot center where atomic blasts take place. Hydrogen turns into helium. Energy is created. the energy is in the form of gamma rays.

Photosphere

The surface of the Sun which glows bright white due to the heat below. As hot gasses rise they carry energy up to the surface with them. The energy escapes through the surface and spreads into space.

Radiative Zone

In this zone many gamma rays change into less harmful forms of energy. The sun is so dense that energy takes millions of years to rise to the surface.

Chromosphere

The Sun’s atmosphere. It’s a layer of gas above the Photosphere. It is only visible during a solar eclipse

Sunspots

Dark blotches on the Sun’s surface. They peak in number about every 11 years. The spots are cooler than the rest of the surface.

 

 

 

Mercury
Symbol
Solid or Gas: Solid surface
Atmosphere: Trace amounts of hydrogen and helium
Moons: None
Other Information: Mercury takes 59 earth days to make a rotation, but only 88 earth days to circle the Sun. The average temperature is -184°C (-300°F) to 427°C (800°F). Mercury is a little larger than the earth's moon. Most of its surface is covered with craters.

 

Venus
Symbol
Solid or Gas: Solid surface
Atmosphere: Very dense; Carbon dioxide (96%), Nitrogen (3%) and trace amounts of other gases
Moons: None

Other Information: Venus is the brightest planet in our sky and can sometimes be seen with the naked eye if you know where to look. The average temperature is 457°C (855°F). Venus is hotter than Mercury. Rotation: 243 earth days. Revolution around the sun: 225 earth days. Venus is the closest planet to the earth.

 

Earth
Symbol
Solid or Gas: Solid surface
Atmosphere: 78% Nitrogen, 21% Oxygen, 1% Other gases
Moons: One: the Moon
Other Information: Earth has more exposed water than land.  Three quarters of the Earth is covered by water. The average temperatures are -89°C (-128°F) to 57.7°C (136°F). Rotation: 24hours. Revolution around the sun: 365 days 5 hours.

 

Mars
Symbol
Solid or Gas: Solid surface
Atmosphere: 95% Carbon dioxide, 3% Nitrogen, 1.6% Argon
Moons: Two: Phobos and Deimos
Other Information: Mars is the home of Olympus Mons, the largest volcano found in the solar system.  It stands about 27 kilometers high with a crater 81 kilometers wide. The average temperatures are -82°C ( -116°F) to 0°C (32°F). Rotation: 24.6 hours. Revolution around the sun: 687 earth days.

 

 

Jupiter
Symbol
Solid or Gas: Gas Giant
Atmosphere: Jupiter's atmosphere includes complicated molecules such as ammonia and methane, as well as simple molecules such as helium, hydrogen, and sulfur. The composition is: 90% hydrogen, 10% helium, .07% methane
Moons: 17 and a ring system: The four Galilean satellitesare: Io, Europa, Ganymede, and Callisto. Other "small moons" in order are; Metis, Adrastea, Amalthea, Thebe, Leda, Himalia, Lysithea, Elara, Ananke, Carme, Pasiphae, Sinope and S/1999 J1
Other Information: Jupiter is the largest planet in the solar system, but it spins very quickly on its axis.  A day on Jupiter lasts only 9 hours and 55 minutes.The average temperatures are -150°C (-101°F). Revolution around the sun: 12 earth years. The Great Red Spot is a storm that has appeared on Jupiter for many years.

 

Saturn
Symbol
Solid or Gas: Gas Giant
Atmosphere: The dramatic appearance of Saturn stems mainly from the spectacular rings. The atmosphere looks much less dramatic. The clouds of Saturn are much less colorful than those of Jupiter. This is because the composition of Saturn's atmosphere includes more sulfur. This adds to Saturn's overall yellow appearance. The composition is: 97% hydrogen, 3% helium, .05% methane
Moons: 28 known moons, many rings: The moon Titan is one of the only moons in the solar system with a significant atmosphere. Other unusual moons of Saturn include the "Death Star" shaped Mimas, the half-black, half-white Iapetus, and the garbage-can shaped Hyperion. Other moons, in order, are; Pan, Atlas, Prometheus, Pandora, Epimetheus, Janus, Enceladus, Tethys, Telesto, Calypso, Dione, Helene, Rhea, Phoebe, S/2000 S1-S/2000 S4 and S/2000 S5-S/2000 S10.
Other Information: Saturn is the second biggest planet, but it’s also the lightest planet.  If there was a bathtub big enough to hold Saturn, it would float in the water. The average temperatures are -170°C (-274°F). Rotation: 10.67 hrs. Revolution around the sun: 29.5 earth years.

 

Uranus
Symbol
Solid or Gas: Gas Planet
Atmosphere: The planet appears to be blue-green because the methane gas of the atmosphere traps red light and does not allow that color to escape. The composition is: 83% hydrogen, 15% helium, 2% methane
Moons: 21 known moons, faint rings: The moons are, in order; Cordelia, Ophelia, Bianca, Cressida, Desdemona, Juliet, Portia, Rosalind, Belinda, and Puck. These moons are part of a group called the "Small Moons". Icy moons of Uranus are; Miranda, Ariel, Umbriel, Titania, Oberon, Caliban, and Sycorax. In 1999, four more Uranian moons were found. They include Prospero, Setebos, Stephano and 1986 U 10.
Other Information: Uranus’ axis is at a 97 degree angle, meaning that it orbits on its side. The average temperatures are -200°C ( -328°F). Rotation: 17.24 hrs. Revolution around the sun: 84 earth years.

 

Neptune
Symbol
Solid or Gas: Gas Planet
Atmosphere: Neptune's atmosphere shows a striped pattern of clouds. This cloud pattern is very similar to that of Jupiter and Saturn. Neptune even has a Great Dark Spot similar to Jupiter's Great Red Spot. The composition of Neptune clouds is thought to be methane molecules. The composition is: 74% hydrogen, 25% helium, 1% methane
Moons: Eight known moons, faint rings: The major moon of Neptune is Triton. It may have active geysers, like those found at Yellowstone Park. Other moons are Despina, Galatea, Larissa, Naiad, Proteus, Thalassa and Nereid.
Other Information: Neptune was discovered in 1846 (over 150 years ago).  Since that time it has still yet to make a complete orbit around the sun, because one Neptune year lasts 165 Earth years! The average temperatures are -210°C ( -346°F). Rotation: 17.24 hrs. Revolution around the sun: 165 earth years.

 

Pluto
Symbol
Solid or Gas: Solid surface
Atmosphere: Very thin, perhaps methane and nitrogen
Moons: One known: Pluto's moon, Charon, is 12,200 miles from the planet and has a diameter of 1,200 km (740 miles). Charon was first seen from Earth in 1978. Pluto and Charon are similar in size, and they orbit each other like a double planet, with the same sides permanently facing each other.
Other Information: Pluto’s orbit sometimes brings it closer to the Sun than Neptune.  It jumped ahead of Neptune on September 5, 1989 and remained there until February, 1999 when it went back to being the farthest.The average temperatures are -229°C (-380°F). Rotation: 6.4 days. Revolution around the sun: 248 years.

 

 

Aeronautics Terms

aeronautics   The scientific study of the design, manufacturing and operation of aircraft.
Bernoulli's Principle   The scientific law which explains the lift of an airplane.
Wright Brothers   Brothers who perfected and flew the first successful motor-powered plane in 1903 at Kitty Hawk, North Carolina.
gravity   The force which pulls all objects towards the center of the earth.
lift   The physical force which allows an aircraft to rise.
thrust   The physical force which drives a rocket, jet engine or airplane forward.
drag   The physical force which slows down an airplane.

 

Rocketry Terms

Dr. Robert Goddard   The American scientist who launched the first successful liquid propellant rocket and accomplished a great deal of early research on rockets.
Werner Von Braun   The German scientist who developed the first guided missile. This person came to the United States after World War II to work on the United States space program.
Sputnik I   The first satellite launched into orbit around the earth by Russia on October 4, 1957.
Yuri Gargarin   The first human to fly into space on April 12, 1961. He was Russian.
Alan Sheppard   The first American astronaut to fly into space on May 5, 1961. He rocketed to a height of 116 1/2 miles, but did not orbit the earth.
John Glenn   The first United States astronaut to orbit the earth on February 20, 1962.
Mercury   The first phase of the manned United States space program. Mercury capsules contained only one astronaut.
Gemini   The second phase of the the manned United States space program. Gemini capsules contained two astronauts and were sued to practice maneuvers in space.
Apollo   The third phase of the manned United States space program. Apollo rockets carried three astronauts and were designed to land a person on the moon.
Neil Armstrong   The first person to step on the moon on July 20, 1969.
Cape Canaveral   The location of the John F. Kennedy Space Center. All major rockets of the United States are launched from this site.
Skylab   An experimental space station launched by the United States in 1973.
Space Shuttle   A reusable spacecraft used by the United States to put astronauts and equipment into orbit around the earth.


Websites for the Solar System, Rocketry, and Aeronautics

 

NASA's Windows on the Universe

Planet Facts

National Air and Space Museum: Exploring the Planets

Directory of Solar System Web Sites

History of Rocketry

A Brief History of Rocketry

Rocketry.org: The Online Resource for Experimental Amateur Rocketry

NASA Aeronautics History

Encyclopedia Smithsonian: Aeronautics and Space History

 

 

 

 

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