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

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


Play button


Play button




Click to flip

15 Cards in this Set

  • Front
  • Back

Astronomical Unit

A unit of measurement equal to Earth's average distance from the sun, about 150 million kilometers

Nuclear fusion

The process by which hydrogen atoms join together in the sun's core to form helium


A loose collection of ice, dust and small rocky particles, typically a long, narrow orbit


Rocky objects revolving around the sun that are too small and numerous to be considered planets


a streak of light in the sky produced by the burning of a meteroid in Earth's atmosphere


an instrument that separates lights into colors and makes an image of the resulting spectrum

light year

the distance that light travels in one year about 9.5 million kilometers


a large cloud of gas and dust in space, spread out in an immense volume


The brilliant explosion of a dying super giant star

neutron star

the small, dense remains of a high-mass star after a super nova

black hole

an object whose gravity is so strong that, nothing, not even light can escape

spiral galaxy

a galaxy with a bulge in the middle anf arms that spiral outward in a pinwheel pattern

big bang

the initial explosion that resulted in the formation and expansion of the universe

dark energy

a mysterious force that appears to be causing the expansion of the universe to accelerate

dark matter

matter that does not give off electromagnetic radiation but is quite abundant in the universe