The radius vector (or line joining sun and planet) sweeps out equal areas in equal times.
He also now answered quite satisfactorily, but too late, the question about the radius vector sent to him months before.
And the way it increases will be for the radius vector to lengthen, so as to sweep out a bigger area.
The anomaly is then the angle BFP which the radius vector makes with the major axis.
Thus the path of the attraction between the two bodies is along the radius vector.
The radius vector is the imaginary straight line joining the centres of the sun and the earth or planet.
In the revolution of a planet round the sun, the radius vector describes equal areas in equal times.
The area covered would always be uniform, because the radius vector would always be uniform in length.
The radius vector of a planet (line adjoining sun and planet) sweeps over equal areas in equal times.
The line drawn from the sun to any point of the orbit (the string from pin to pencil point) is a radius vector.
radius vector
