Create an account
Polish astronomer who produced a workable model of the solar system with the sun in the center (1473-1543)
Big Bang Theory
the theory that proposes that the universe originated as a single mass, which subsequently exploded
a galaxy shaped like a round or flattened ball, generally containing only old stars
the apparent change in frequency of electromagnetic or sound waves caused by the relative motions of the source and the observer
n. The throwing off or back of light, heat, sound, or any form of energy that travels in waves.
a lens that is thicker in the middle than at the edges and bends light rays towards one another
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
It looks like your browser might be zoomed in or out. Your browser needs to be zoomed to a normal size to record audio.
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