Create an account
the scientific study of the universe; it includes the observation and interpretation of celestial bodies and phenomena
astronomical unit (AU)
average distane from Earth to the sun; 1.5 X 10 to the 8th power, or 150 million kilometers
an eclipse of the sun; a solar eclipse occurs when the moon moves in a line directly between Earth and the sun, casting a shadow on Earth.
an eclipse of the moon: a lunar eclipse occurs when the moon passes through Earth's shadow
Please allow access to your computer’s microphone to use Voice Recording.
Having trouble? Click here for help.
We can’t access your microphone!
Click the icon above to update your browser permissions and try again
Reload the page to try again!Reload
Press Cmd-0 to reset your zoom
Press Ctrl-0 to reset your zoom
Please upgrade Flash or install Chrome
to use Voice Recording.
For more help, see our troubleshooting page.
Your microphone is muted
For help fixing this issue, see this FAQ.
Star this term
You can study starred terms together