The time it takes an object to complete one rotation on its axis
period of rotation
The average distance from Earth to the Sun
Astronomical Unit
The time it takes an object to travel once around the Sun
period of revolution
An increase in temperature caused by energy trapped by a planet's atmosphere
greenhouse effect
An inner planet
terrestrial planet
The four largest moons of Jupiter
Galilean Moons
The streak of light in Earth's atmosphere made by a glowing meteoroid
Meteor
Meteorites often form_______
impact craters
Name for a meteoroid that strikes a planet or moon
meteorite
This causes streaks of light called meteors
meteoroid
Which solar system object is the largest - Jupiter, Neptune, the Sun or Saturn?
the Sun
The asteroid belt is made up of _______
millions of small rocky objects
What happens to a planet's speed as it orbits the Sun?
it increases then decreases
The thing that makes planets orbit around the Sun
gravitational pull of the Sun
The greenhouse effect is ______
energy trapped by the atmosphere
How are the terrestrial planets similar?
similar rocky surfaces
Which inner planet is the hottest?
Venus
How does Earth differ from other inner planets?
Its surface is covered by large amounts of liquid water
Which two gases make up most of the outer planets?
hydrogen and helium
Shape of dwarf planets
spherical
A bright streak of light in Earth's atmosphere
a meteor
Asteroids are made of _______
rock and ice
Name the terrestrial planets
Mercury, Venus, Earth and Mars
An Astronomical Unit is the average distance from _____ to ______
Earth to the Sun
Name three characteristics of all planets
1) each exceeds the total body mass of nearby objects
2) they have a nearly spherical shape
3) they make an elliptical orbit around the Sun
The thick inner layer of Saturn is made of which material?
liquid hydrogen
Three things found on Mercury's surface
1) impact craters
2) lava flows
3) sand dunes
What is the primary cause of the extremely high temperatures on the surface of Venus?
the greenhouse effect
What is a meteorite?
A fragment of rock that strikes a planet or moon
What gives Mars its reddish color?
soil rich in iron oxide
What features of Earth make it suitable for supporting life as we know it?
Earth's protective atmosphere + presence of liquid water + moderate temperatures caused by the greenhouse effect = variety of life as we know it.
The inner planets are also called the _____
terrestrial planets
The outer planets are also called _____
gas giants
The relative size of the inner planets is ______
Similar or smaller than Earth
The relative size of the outer planets is _____
much larger than Earth
The main material the inner planets are made of
solid rocky material and metal
The main material the outer planets are made of
ice and gas
The general structure of the inner planets
solid or liquid core, sometimes an outer core, mantle and crust
The general structure of the outer planets
a thick gas and liquid layer covering a small, solid core
Number of moons the inner planets have
0 except Earth which has 1
Number of moons the outer planets have
Many moons - anywhere from 13 - 63
Do any of the inner planets have rings?
No
Do all of the outer planets have rings?
Yes
Which space objects orbit the Sun?
planets, dwarf planets asteroids and comets
Which space objects have spherical shapes?
planets and dwarf planets
Do asteroids have other objects orbiting near them?
No
Which space objects have more mass than objects in nearby orbits
only planets - no others
Terrestrial planets
The planets closest to the Sun, are made of rock and have solid outer layers
Greenhouse effect
Occurs when a planet's atmosphere traps solar energy and causes the surface temperature to increase
Name the Galilean (four largest) moons of Jupter
Io, Europa, Ganymede and Callisto
A round depression formed on the surface of a planet, moon or other space object by the impact of a meteorite
impact crater
A small rocky particle that moves through space
meteoroid
Millions of small, rocky objects that orbit the Sun in a belt between the orbits of Mars and Jupiter
asteroid
Average distance from Earth to the Sun
Astronomical Unit = 150 million km
made of gas, dust and ice and moves around the Sun in an oval-shaped orbit
comet
Which dwarf planet used to be a planet?
Pluto
The largest object in the solar system
The Sun
What type of object is the Sun?
A star
What is the largest object in the solar system?
The Sun - ten times the size of the largest planet, Jupiter
What is the Sun made of?
Mostly hydrogen gas
The Sun makes up ___% of the solar system's mass
99
How is energy produced by the Sun?
Nuclear fusion inside the Sun produces energy
How many planets does the Sun's light shine on each day?
All of them
A spherical object that orbits the Sun that is not a moon of another planet adn in a region of the solar system wehre there are many other objects orbiting near it.
Dwarf planet
How are the inner planets similar?
They are made of rock and metal. They hahve cores made of iron and nickel and have solid outer layers.