Study your flashcards anywhere!

Download the official Cram app for free >

  • Shuffle
    Toggle On
    Toggle Off
  • Alphabetize
    Toggle On
    Toggle Off
  • Front First
    Toggle On
    Toggle Off
  • Both Sides
    Toggle On
    Toggle Off
  • Read
    Toggle On
    Toggle Off
Reading...
Front

How to study your flashcards.

Right/Left arrow keys: Navigate between flashcards.right arrow keyleft arrow key

Up/Down arrow keys: Flip the card between the front and back.down keyup key

H key: Show hint (3rd side).h key

A key: Read text to speech.a key

image

Play button

image

Play button

image

Progress

1/10

Click to flip

10 Cards in this Set

  • Front
  • Back
astronomical unit (AU)
Average distance from Earth to the sun; 1.5 x 108 km, or 93 x 106 mi. (p. 6)
galaxy
A large system of stars, star clusters, gas, dust, and nebulae orbiting a common center of mass. (p. 8)
light-year (ly)
A unit of distance. The distance light travels in 1 year. (p. 7)
Milky Way
The hazy band of light that circles our sky. Produced by the glow of our galaxy. (p. 8)
Milky Way Galaxy
The spiral galaxy containing our sun. Visible in the night sky as the Milky Way. (p. 8)
planet
A small, nonluminous body formed by accretion in a disk around a protostar. (p. 6)
scientific notation
The system of recording very large or very small numbers by using powers of 10. (p. 6)
solar system
The sun and its planets, asteroids, comets, and so on. (p. 6)
spiral arm
Long spiral pattern of bright stars, star clusters, gas, and dust. Spiral arms extend from the center to the edge of the disk of spiral galaxies. (p. 8)
star
A globe of gas held together by its own gravity and supported by the internal pressure of its hot gases, which generate energy by nuclear fusion. (p. 6)