- relatively small and rocky
- huge, gas giants
a cloud of gas and/or dust in space
colliding matter in space forming small, irregular shaped bodies
the science that studies the universe
Greeks believed the Earth was a sphere that stayed motionless at the center of the universe
Aristarchus was the first Greek to believe in a sun-centered (heliocentric) universe
each planet moves slightly eastward among the stars, then appears to stop and reverse direction for a time, then resume an eastward motion
an oval-shaped path made by the planets around the sun
the average distance between Earth and the sun
one of the main motions of Earth
the other main motion of Earth
very slow motion in Earth's axis over a period of 26,000 years
at perihelion, Earth is closest to the sun, about 147 million kilometers away
at aphelion, Earth is farthest from the sun, about 152 million kilometers away
the moon is closest to Earth
the moon is furthest from Earth
phases of the moon
a change in the amount of the moon that appears lit
when the moon blocks the sun and casts a dark shadow on Earth
when the moon moves within Earth's shadow
round depressions in the surface of the moon
splash marks that radiate outward for hundreds of kilometers
mare (plural: maria)
the dark, relatively smooth area on the moon's surface
found on the surface of the moon, these look similar to valleys and trenches
composed of igneous rock, glass beads, and fine lunar dust (moon dirt)
Imaginary globe where Earth is at the center and provides an easy way of describing position of objects in sky
how much matter is in an object
Which scientist proposed three laws of planetary motion?
What is the shape of a planet's orbit?
second law of planetary motion
each planet revolves so that an imaginary line connecting to the sun sweeps over equal areas and equal time intervals
Which scientist was the first to use a telescope in astronomy?
third law of planetary motion
the square of the length of time it takes a planet to orbit the sun is proportional to the cube of its mean distance to sun
What movement of Earth is responsible for night and day?
What is the moon's period of rotation?
When the moon's phases are changing from new to full, the moon is said to be in what phase?
What must happen for a solar eclipse to occur?
the moon must move directly in line between Earth and the Sun
round depressions on the moon's surface
How did Maria form on the moon?
asteroids punctured the lunar surface allowing magma to bleed out
Why does the moon have more craters on Earth?
the moon has no atmosphere, so incoming objects don't burn up in the sky, they hit the moon directly
How old is the moon?
4.5 billion years old
What information supports the giant-impact hypothesis of the moon's formation?
- made of iron-poor mantle and crustal rocks (created lack of big iron core on the moon)
- material lost water in debris ejection (no water on moon)
Which planets have rings?
Jupiter, Saturn, Neptune, & Uranus
Main difference between Jovian and terrestrial planets
Jovian planets have gas and terrestrial planets have earth/land
How does crater density tell the moon' geologic history.
- the greater the crater density, the older the surface must be
- scientists concluded that the moon evolved in three phases: the original crust, maria basins, and rayed craters
The formation of the solar system from a huge cloud of dust and gases is what theory?
the Nebular Theory
What two main gases do Jovian planets have?
Hydrogen & Helium
Which types of minerals are more abundant on terrestrial than Jovian planets?
Which planet shows evidence of water erosion?
Which planet has a cratered surface?
Which planet has the greatest temperature extremes?
Which planet has high surface temperatures and a dense CO2 atmosphere?
Which thickly clouded planet reveals topography with plains, highlands, & volcanic structures?
What planet is Mons Olympus found on?
Which planet appears as a reddish ball with varied dark regions of changing intensity?
What force is currently responsible for shaping Mars' surface?
Which features on Mars indicate a possibility of the presence of liquid water?
gullies and stream-like channels
Which planet is second only to the moon in brilliance in the night sky?
Which planet has a greater mass than the combined mass of all remaining planets and moons?
Which of Jupiter's moons is volcanically active?
Which planet has the Great Dark Spot?
Which planet's axis of rotation is almost parallel with its plane of orbit?
What is Jupiter's Great Red Spot?
the vortex of a storm
small, rocky bodies usually found orbiting between Mars and Jupiter
Where do most asteroids lie?
between Mars and Jupiter
the glowing head of a comet
In what region do we find comets with short orbital periods?
meteoroids that enter Earth's atmosphere and burn up