Chapter 28 Vocab Flashcards
Space object built of solid particles that can form planets through collisions and mergers.
Planetesimal
A planet’s apparent backward movement in the sky.
Retrograde motion
An oval that is centered on two points called foci; the shape of a planet’s orbit.
Ellipse
Ratio of the distance between the foci to the length of the major axis; defines the shape of a planet’s elliptical orbit.
Eccentricity
Earth’s average distance from the sun.
Astronomical unit
Rocky-surfaced, relatively small, dense inner planets closest to sun.
Terrestrial planet
A line of cliffs produced by erosion or faulting.
Scarp
Large, gaseous planet that is very cold at its surface, has ring systems, many moons, lacks solid surface.
Gas giant planet
An object that, due to its own gravity, is spherical in shape, orbits the Sun, is not a satellite, and has not cleared the area of its orbit of smaller debris.
Dwarf Planet
Piece of interplanetary material that comes toward Earth and enters its atmosphere.
Meteoroid
Streak of light produced when a meteoroid falls toward Earth and burns up in Earth’s atmosphere.
Meteor
A small fragment of an orbiting body that has fallen to Earth, generating heat; does not completely burn up in Earth’s atmosphere and strikes Earth’s surface, sometimes causing an impact crater.
Meteorite
Region of the space that lies outside the orbit of Neptune, 30-50 AU, where small solar system bodies that are mostly rock and ice probably form.
Kuiper Belt
Small, eccentrically orbiting body made of rock and ice which have one or more tails that point away from the sun.
Comet
Occurs when Earth intersects a cometary orbit and comet particles burn up as they enter Earth’s upper atmosphere.
Meteor Shower
