Mercury and Saturn

• The sun and moon, for two
• Stars and planets
• Areas of expertise
• Crystal balls, for example
• Heavenly array
• Domains of influence
• Fields of activity
• Mars, Venus, etc

Wikipedia Word definitions in Wikipedia
The Synchronized Position Hold Engage and Reorient Experimental Satellite (SPHERES) are a series of miniaturized satellites developed by MIT 's Space Systems Laboratory for NASA and US Military, to be used as a low-risk, extensible test bed for the development ...