Voyager II

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setup

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Animation of Trajectory

Voyager II left Earth on 1977 August 20, and reached Jupiter on 1979 July 10. It then cruised passed Saturn on 1981 August 26, followed by Uranus on 1986 January 24 and finally Neptune on 1989 August 25. By using these dates we can crudely define the trajectory of Voyager II by using the SetCoordinates function.

{{d0,p0},{d1,p1},
{d2,p2},{d3,p3},{d4,p4}} =
Apply[{ModifiedJulianDay[#1],
Coordinates[#2, #1,
ViewPointSun]}&,
{{{1977,8,20}, Earth},
{{1979,7,10}, Jupiter},
{{1981,8,26}, Saturn},
{{1986,1,24}, Uranus},
{{1989,8,25}, Neptune}}, 1];

SetCoordinates[Voyager2,
Which @@ Expand[{
d < d0, p0,
d < d1, p0+((p1-p0)*(d-d0))/(d1-d0),
d < d2, p1+((p2-p1)*(d-d1))/(d2-d1),
d < d3, p2+((p3-p2)*(d-d2))/(d3-d2),
d < d4, p3+((p4-p3)*(d-d3))/(d4-d3),
True, p4+((p4-p3)*(d-d4))/(d4-d3)}
], d];

Having defined a new object called Voyager2 we can animate its path as it visits the outer planets using the SolarSystemPlot function. In the animation below Voyager2 is the white dot spiraling outwards from the center.

Do[dd={y,m,1};
SolarSystemPlot[dd,
Distance34 AU,
ViewPointSun,
Epilog{RGBColor[1,1,1],
PointSize[0.02],
Point[Take[
Coordinates[Voyager2,dd,
ViewPointSun], 2]]}],
{y,1977,1991}, {m,1,12,6}];