The Cosmic Perspective: A Modern View of the Universe (Chapter 1) Flashcards
The plane of Earth’s orbit around the Sun
Ecliptic Plane
The amount by which a planet’s axis is tilted with respect to a line perpendicular to the ecliptic plane
Axis Tilt (Of a planet in our solar system)
Another term for Solar System
Star System
The portion of the Milky Way Galaxy that is located relatively close (Within a few hundred to a couple of thousand light-years) to our Sun
Local Solar Neighborhood
Generally, the region of our solar system beginning at about the orbit of Jupiter
Outer Solar System
Spacecraft that go into the orbit of another world for long-term study
Orbiters (of other worlds)
The name given to the event is thought to mark the birth of the universe
Big Bang
The group of about 40 galaxies to which the Milky Way Galaxy belongs
Local Group
The orbital motion of one object around another
Revolution
The name is used both for our galaxy and for the band of light we see in the sky when we look into the plane of our galaxy
Milky Way
A moderately large object that orbits a star and shines primarily by reflecting light from its star
Planet
Term for a cluster of stars
Star Cluster
A great island of stars in space, containing millions, billions, or even trillions of stars, all held together by gravity and orbiting a common center
Galaxy
The idea that the space between galaxies or clusters of galaxies is growing with time
Expansion (of the universe)
An object that orbits the Sun and is massive enough for its gravity to have made it nearly round in shape, but doesn’t qualify as the official planet because it hasn’t cleared its orbital neighborhood
Dwarf Planet
Another term for a cluster of galaxies
Galaxy Cluster
The distance that light can travel in 1 year, which is 9.46 trillion kilometers
Lightyear (ly)
Any object orbiting another object
Satellite
The supercluster of galaxies to which the Local Group belongs
Local Supercluster
A large, glowing ball of gas that generates energy through nuclear fusion in its core
Star
A star (sometimes more than one star) and all objects that orbit it
Solar System
The path followed by a celestial body because of gravity; an orbit may be bound (elliptical) or unbound (parabolic or hyperbolic)
Orbit
The average distance (semimajor axis) of Earth from the Sun, which is about 150 million kilometers
Astronomical Unit (AU)
An alternative name for the universe
Cosmos
The portion of the entire universe that, at least in principle, can be seen from Earth
Observable Universe
The sum total of all matter and energy
Universe
An asteroid, comet, or other object that orbits a star, but is too small to qualify as a planet or dwarf planet
Small Solar System Body
A graph that plots rotational (or orbital) velocity against distance from the center for any object or set of objects
Rotation Curve
Another name for an elliptical galaxy
Spheroidal Galaxy
M31, the Great Galaxy in Andromeda, the nearest large spiral galaxy to the Milky Way
Andromeda Galaxy
A relatively small and rocky object that orbits a star
Asteroids
