Note:  Do not rely on this information. It is very old.

Radius Vector

Radius Vector is a line drawn from a centre of force to a body describing an orbit round that centre, and is a term of special application in astronomy, where it usually denotes the line drawn from the sun to the position of a planet at any time. It is obvious that this line is continually changing its length and direction.

“Now faith is being sure of what we hope for and certain of what we do not see.”
Hebrews 11:1