Create an account
In Ptolemy's geocentric solar system, the large circle on which a planet's epicycle moved around the Earth.
The point where an inferior planet is as far away from the Sun as it can be (as seen from the Earth).
The point where a superior planet is as far away from the Sun as it can be (as seen from the Earth).
A measure of how an object resists accelerating when acted upon by a force. It is proportional the amount of matter in an object.
The philosophical stand that says a simpler explanation is more likely to be correct than a complicated one.
The larger bodies that formed early in the solar nebula that were chemically differentiated.
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