Exoplanets And Planets: The Truth Is Out There
Exoplanets are in the news, and not just because Google did a doodle on them, either. On February 22, 2017, news of the discovery of seven new exoplanets was announced by NASA. This may be a new word for you non-NASA geeks out there. Let’s examine the difference between planets and exoplanets. A planet is sometimes also called a major planet. It’s any of the …
Read more in this article about some frequently asked questions and fun facts related to our definitions.
Origin of reference frame
First recorded in 1920–25
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
A basis of a four-dimensional coordinate system in which the first coordinate is understood as a time coordinate, while the other three coordinates represent spatial dimensions. Inertial frames and non-inertial frames are both examples of reference frames. Also called frame of reference See also General Relativity space-time Special Relativity.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.