astronomical frame of reference
a frame of reference in which the sun or center of mass of the universe is fixed and which does not rotate with respect to the fixed stars.
Five English Words That Are Utterly Unique
Read more in this article about some frequently asked questions and fun facts related to our definitions.
Pluto gains a fourth moon, but what should it be named?
Pluto may have been demoted to a dwarf planet in 2006, but that hasn’t stopped astronomers from studying this intriguing plutoid. NASA recently announced the discovery of a fourth moon, be it a “mini-moon,” circling the former planet. Dubbed “P4” for the time being, the hunt is on for an appropriate name. The practice of naming planets after gods and goddesses can be traced back …
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019