synodicPeriod_days

Given a predicate that represents a relationship or action between entities, generate a one-sentence description explaining its meaning.  
# Instructions
Focus on describing the relationship, not the entities themselves. 
# Response Format
Begin the description with \' Indicates...\'

Predicate: synodicPeriod_days

Indicates the length of time, measured in days, between successive identical configurations (e.g., conjunctions or oppositions) of two orbiting bodies as seen from a given reference point.