Download Name: Pd: _____ Ast: _____ Solar System Study Guide Vocabulary

Name: ______________________________
Solar System Study Guide
Pd: _____
Ast: _____
I.
Vocabulary
a) Study your vocabulary using C5 Solar System Vocab & your blue vocab flash cards
1) Solar System - A star together with the group of planets and other celestial bodies that are held by its
gravitational attraction and revolve around it
2) Celestial Objects - Objects such as planets, moons, and stars that are located in the sky or in space
3) Star - A ball of gas in space that produces its own light and heat
4) Sun - The star around which Earth and other planets revolve and from which they receive heat and light
5) Satellite - An object held in orbit by the gravity of a larger celestial body; for example a moon orbiting a
planet or a man-made object orbiting Earth
6) Planets - Large celestial bodies that orbit the star in the center of a solar system, have a “nearly
spherical shape”, and whose mass is significantly larger than other nearby objects
7) Period of Revolution - The time it takes for an object to travel once around the Sun
8) Period of Rotation - The time it takes for an object to complete one spin around its own axis
9) Atmosphere - A layer of gasses surrounding a planet that is held in place by the planet’s gravity
10) Astronomical Unit (AU) - Unit of measure in space equal to the average distance between Earth and the
Sun.
11) Dwarf Planet - A spherical object that orbits a star but whose mass is not larger than other nearby
objects
12) Moon - A celestial body that revolves around a planet
13) Gravity - The force of attraction that pulls objects toward each other; the force that controls the motion
of our solar system
14) Terrestrial - Rocky and Earth-like
15) Asteroid - Large and small rocks or metallic masses orbiting the Sun; made up of materials similar to
those that formed the planets
16) Meteoroid - A natural chunk of rock or dust existing outside of Earth’s atmosphere
17) Comet - A celestial body of ice, dust, and rock with an elongated and elliptical orbit
II.
Models of the Solar System
1) Compare the geocentric and heliocentric models of the solar system.
The geocentric model proposed that all celestial objects orbit the Earth, while the heliocentric model
proposes that celestial objects orbit the Sun.
2) What do the words, “geocentric” and “heliocentric”, mean?
“geocentric” means “Earth centered”
“heliocentric” means “Sun centered”
3) Which famous astronomers are responsible for proposing and confirming the heliocentric model?
Copernicus proposed the heliocentric model and Galileo confirmed it with his observations.
III. Formation of the Solar System
4) What is a nebula and why is it important?
A nebula is an extremely large “space cloud” made of dust and gas. These are the places where stars are
“born”.
5) Briefly describe the “Nebular Theory”.
Nebular Theory says that solar systems are formed as nebulae condense around areas of higher mass.
These points where matter condenses eventually become stars, and the dust & gas surrounding the star
condenses to form planets through a process called “accretion”.
6) What force causes matter to condense around areas of higher mass as described in the Nebular Theory?
Gravity is responsible for causing areas of higher mass to condense to form stars/planets from a nebula.
7) Describe the distribution of mass in our solar system.
99% of the mass in the universe is contained in the Sun, while the other 1% makes up the planets.
IV. The Role of Gravity
8) What two factors affect the force of gravity?
Gravity is affected by the masses of the objects and the distance between them.
9) Identify two ways gravity influences the objects in our solar system.
Gravity is responsible for forming the Sun and planets into spherical shapes as well as keeping the planets in
elliptical orbits around the Sun.
V.
Measuring Distances Within the Solar System
10) What does “AU” stand for and what does it mean?
“AU” stands for Astronomical Unit. It refers to the average distance between the Sun and Earth; and it is
used to describe distances within the Solar System.
11) What is the value of 1AU in km? 1AU is about 150 million Km.
VI. The Sun
12) What two elements make up 99.9% of the Sun? Hydrogen (92.1%) and Helium (7.8%)
13) What process is responsible for releasing radiant and thermal energy in the Sun? Nuclear Fusion
VII. Planets
14) List the 3 characteristics a celestial body must have to be classified as a “planet”.
1 – Orbit the Sun
2 – Enough mass that its own gravitational force shapes it into a spherical shape
3 – Enough gravitational force to “clear” its orbit of other large objects either by absorbing them or
deflecting them out into space.
15) List the planets in order from the Sun.
Mercury – Venus – Earth – Mars – Jupiter – Saturn – Uranus – Neptune
16) What are some common characteristics of the inner planets?
Inside the Asteroid
Few Moons
Faster Orbits
Belt
Warmer
Relatively Small
Temperatures
17) What are some common characteristics of the outer planets?
Outside the Asteroid
Many Moons
Ring Systems
Belt
Cooler Temperatures
Very Large
Slower Orbits
18) Which is the biggest planet? Jupiter
19) Which is the smallest planet? Mercury
20) Which is the hottest planet? Venus (atmosphere)
21) Which is the coldest planet? Neptune (furthest from Sun)
22) Which is the least-dense planet? Saturn
23) Which planet rotates nearly “sideways”? Uranus
24) As planets get further from the Sun, what pattern emerges with their…
a) Temperatures? Temperatures get cooler farther from the Sun (except for Venus).
b) Revolution? Revolutions take longer the further out from the Sun a planet orbits.
c) Orbital Speed? Planets move slower the further out from the Sun they orbit.
VIII. Dwarf Planets
25) Compare “dwarf planets” to “planets”. How are they similar? How are they different?
Dwarf planets are spherical objects that orbit the Sun, but they have not “cleared” their orbit of other large
objects.
26) How is Ceres unique among dwarf planets? Ceres is the only dwarf planet in the Asteroid Belt.
27) Where are most of the dwarf planets located? Most of the dwarf planets are in the Kuiper Belt & Scattered
Disc
IX. Other Celestial Objects
28) What is an asteroid? A chunk of rock/metal of varying size/mass that orbits the Sun
29) In which regions within the Solar System are most asteroids located? The Asteroid Belt
30) What is a comet? A small chunk of ice/dust/rock that orbits the Sun in an elongated elliptical orbit
31) In which region within the Solar System are most comets thought to originate from? The Scattered Disc