an object must be orbiting the Sun, nearly spherical, and large enough to clear all matter from its orbital zone.
is defined as an object that is orbiting the Sun, is nearly spherical, but has not cleared matter from its orbital zone and is not a satellite.
Small Solar System Bodies
All objects in the solar system that are not planets, dwarf planets, or moons.
astronomical Unit (AU)
a measurement for distances based on the distance from earth to the sun
The name given to the four inner planets: Mercury, Venus, Earth, and Mars
Jupiter, Saturn, Uranus, and Neptune
a mass that travels through space and is composed of rock particles and dust mixed with frozen water, methane, and ammonia; tends to vaporize and break up after passing close to the Sun many times
a hypothetical huge collection of comets orbiting the sun far beyond the orbit of Pluto
a disk-shaped region of small icy bodies some 30 to 100 AU from the Sun; the source of short-peroid comets
small, rocky bodies orbiting the Sun and lying mainly in a narrow belt between Mars and Jupiter.
remnants of comets and asteroids in space
A streak of light in the sky produced by the burning of a meteoroid in Earth's atmosphere
an event in which many meteorites fall in a short peroid of time.
stony or metallic object that is the remains of a meteoroid that has reached the earth's surface
Protoplanet Nebular Model
the earliest stage in the formation of a planet.
geocentric model of the structure of the solar system that uses epicycles to explain retrograde motion.
heliocentric, or suncentered solar system model developed by Nicholas Copernicus in 1543
Kepler's Laws of Planetary Motion
three laws describing the motion of the planets in the solar system.
Kepler's First Law
states that each planet moves in an orbit that has the shape of an ellipse, with the Sun located at one focus
Kepler's Second Law
states that an imaginary line betweent the Sun and a planet moves over equal areas of the ellipse during equal time intervals.
Kepler's Third Law
states that the square of the peroid of a planet's orbit is proportional to the cube of that planet's semimajor axis.