; ; ******************************** ; Death of Solar System Simulation ; Toby Skinner ; December 15, 2011 ; ******************************** ; ; Nomenclature note: The term "Orbital Velocity" is actually "Speed" ; with a constant orbital direction ; globals [OriginalMassSun MassSun MassSunM1 SizeSun SizeMercury SizeVenus SizeEarth SizeMars SizeJupiter SizeSaturn SizeUranus SizeNeptune TrueOrbitalRadiusMercury TrueOrbitalRadiusVenus TrueOrbitalRadiusEarth TrueOrbitalRadiusMars TrueOrbitalRadiusJupiter TrueOrbitalRadiusSaturn TrueOrbitalRadiusUranus TrueOrbitalRadiusNeptune DisplayOrbitalRadiusMercury DisplayOrbitalRadiusVenus DisplayOrbitalRadiusEarth DisplayOrbitalRadiusMars DisplayOrbitalRadiusJupiter DisplayOrbitalRadiusSaturn DisplayOrbitalRadiusUranus DisplayOrbitalRadiusNeptune DegreesMercury DegreesVenus DegreesEarth DegreesMars DegreesJupiter DegreesSaturn DegreesUranus DegreesNeptune ColorSun ColorMercury ColorVenus ColorEarth ColorMars ColorJupiter ColorSaturn ColorUranus ColorNeptune OrbitalVelocityMercury OrbitalVelocityVenus OrbitalVelocityEarth OrbitalVelocityMars OrbitalVelocityJupiter OrbitalVelocitySaturn OrbitalVelocityUranus OrbitalVelocityNeptune PlotOrbitalVelocityMercury PlotOrbitalVelocityVenus PlotOrbitalVelocityEarth PlotOrbitalVelocityMars PlotOrbitalVelocityJupiter PlotOrbitalVelocitySaturn PlotOrbitalVelocityUranus PlotOrbitalVelocityNeptune IncDegreesMercury IncDegreesVenus IncDegreesEarth IncDegreesMars IncDegreesJupiter IncDegreesSaturn IncDegreesUranus IncDegreesNeptune XCoordMercury XCoordVenus XCoordEarth XCoordMars XCoordJupiter XCoordSaturn XCoordUranus XCoordNeptune YCoordMercury YCoordVenus YCoordEarth YCoordMars YCoordJupiter YCoordSaturn YCoordUranus YCoordNeptune MinPlanetVelocityThreshold ScaleFactorPlanetSize ConstantG EarthYearsCounter LastPlanetErase] to setup ; ; Initialize Solar Syatem clear-all ; ; Initialize EarthYearsCounter to zero set EarthYearsCounter 0 ; ; Initialize the beginning mass of the Sun set OriginalMassSun 2 * 10 ^ 30 set MassSun OriginalMassSun ; ; Initialize the relative sizes, orbital radii, positions, and colors ; for the Sun and the planets set SizeSun 40 set SizeMercury 5 set SizeVenus 12 set SizeEarth 13 set SizeMars 7 set SizeJupiter 143 set SizeSaturn 121 set SizeUranus 51 set SizeNeptune 49 ; ; Scale sizes of planets to accomodate display set ScaleFactorPlanetSize (4 - 1) / (143 - 5) set SizeMercury SizeMercury * ScaleFactorPlanetSize + 2 set SizeVenus SizeVenus * ScaleFactorPlanetSize + 2 set SizeEarth Sizeearth * ScaleFactorPlanetSize + 2 set SizeMars SizeMars * ScaleFactorPlanetSize + 2 set SizeJupiter SizeJupiter * ScaleFactorPlanetSize + 2 set SizeSaturn SizeSaturn * ScaleFactorPlanetSize + 2 set SizeUranus SizeUranus * ScaleFactorPlanetSize + 2 set SizeNeptune SizeNeptune * ScaleFactorPlanetSize + 2 ; ; True orbital radii (m km) ; E.g., True orbital radius of Mercury = 58 x 10^9 m set TrueOrbitalRadiusMercury 58 set TrueOrbitalRadiusVenus 108 set TrueOrbitalRadiusEarth 150 set TrueOrbitalRadiusMars 228 set TrueOrbitalRadiusJupiter 778 set TrueOrbitalRadiusSaturn 1427 set TrueOrbitalRadiusUranus 2871 set TrueOrbitalRadiusNeptune 4497 ; ; Compress OrbitalRadii to accomodate display set DisplayOrbitalRadiusMercury log TrueOrbitalRadiusMercury 1.01 ; 408 set DisplayOrbitalRadiusVenus log TrueOrbitalRadiusVenus 1.01 ; 471 set DisplayOrbitalRadiusEarth log TrueOrbitalRadiusEarth 1.01 ; 504 set DisplayOrbitalRadiusMars log TrueOrbitalRadiusMars 1.01 ; 546 set DisplayOrbitalRadiusJupiter log TrueOrbitalRadiusJupiter 1.01 ; 669 set DisplayOrbitalRadiusSaturn log TrueOrbitalRadiusSaturn 1.01 ; 730 set DisplayOrbitalRadiusUranus log TrueOrbitalRadiusUranus 1.01 ; 800 set DisplayOrbitalRadiusNeptune log TrueOrbitalRadiusNeptune 1.01 ; 845 ; ; Initialize orbital position degrees to zero set DegreesMercury 0 set DegreesVenus 0 set DegreesEarth 0 set DegreesMars 0 set DegreesJupiter 0 set DegreesSaturn 0 set DegreesUranus 0 set DegreesNeptune 0 ; ;Initialize orbital velocities to zero set OrbitalVelocityMercury 0 set OrbitalVelocityVenus 0 set OrbitalVelocityEarth 0 set OrbitalVelocityMars 0 set OrbitalVelocityJupiter 0 set OrbitalVelocitySaturn 0 set OrbitalVelocityUranus 0 set OrbitalVelocityNeptune 0 ; ; Create Sun and eight planets create-turtles 1 ; Sun [set color 45 set xcor 0 set ycor 0 set shape "dot" set size SizeSun] create-turtles 1 ; Mercury [set color 24 set xcor (max-pxcor) / 1000 * DisplayOrbitalRadiusMercury set ycor 0 set shape "dot" set size SizeMercury set pen-size 0.0001 pen-down] create-turtles 1 ; Venus [set color 35 set xcor (max-pxcor) / 1000 * DisplayOrbitalRadiusVenus set ycor 0 set shape "dot" set size SizeVenus set pen-size 0.0001 pen-down] create-turtles 1 ; Earth [set color 73 set xcor (max-pxcor) / 1000 * DisplayOrbitalRadiusEarth set ycor 0 set shape "dot" set size SizeEarth set pen-size 0.0001 pen-down] create-turtles 1 ; Mars [set color 15 set xcor (max-pxcor) / 1000 * DisplayOrbitalRadiusMars set ycor 0 set shape "dot" set size SizeMars set pen-size 0.0001 pen-down] create-turtles 1 ; Jupiter [set color 33 set xcor (max-pxcor) / 1000 * DisplayOrbitalRadiusJupiter set ycor 0 set shape "dot" set size SizeJupiter set pen-size 0.0001 pen-down] create-turtles 1 ; Saturn [set color 125 set xcor (max-pxcor) / 1000 * DisplayOrbitalRadiusSaturn set ycor 0 set shape "dot" set size SizeSaturn set pen-size 0.0001 pen-down] create-turtles 1 ; Uranus [set color 95 set xcor (max-pxcor) / 1000 * DisplayOrbitalRadiusUranus set ycor 0 set shape "dot" set size SizeUranus set pen-size 0.0001 pen-down] create-turtles 1 ; Neptune [set color 113 set xcor (max-pxcor) / 1000 * DisplayOrbitalRadiusNeptune set ycor 0 set shape "dot" set size SizeNeptune set pen-size 0.0001 pen-down] ; ; Initialize flag for erasing the last planet set LastPlanetErase 0 ; ; Set up Plots setup-plot ; end to rotateplanets ; ; Update the simulation view - rotate the planets multiple Earth-years, ; until "paused" manually or "stopped" by the disappearance of all of the planets loop [ ; ; Don't update Sun size and mass during erasure of Mercury orbit if (LastPlanetErase = 0) [ ; ; Update the mass of the Sun set MassSunM1 MassSun set MassSun (MassSun * (100 - AnnualSunMassLossPercent) / 100) ; ; Update display size of the Sun ; Size (radius) of Sun reduces as the cube-root of the mass (~volume) reduces set SizeSun SizeSun * ((MassSun ^ (1 / 3)) / (MassSunM1 ^ (1 / 3))) ask turtle 0 [set size SizeSun] ] ; ; At 0% Sun mass loss, 360/IncDegreesEarth = 360/0.1139 = 3160 updates per revolution ; repeat 3160 ; 3160 angular increments per one revolution of the Earth ; (one present-day Earth-year) [ ; ; Compute new orbital rotation velocities for each planet ; Velocity = sqrt ( G x MassSun / OrbitalRadius ) ; G = 6.67x10^-11 m^3/kgsec^2 ; m/s = sqrt(m^2/s^2) = sqrt(((m^3)/(kg s^2))*(kg)/(m/s))) ; set ConstantG 6.67 * 10 ^ -11 ; set OrbitalVelocityMercury sqrt ( ( ConstantG * MassSun ) / (TrueOrbitalRadiusMercury * 10 ^ 9) ) set OrbitalVelocityVenus sqrt ( ( ConstantG * MassSun ) / (TrueOrbitalRadiusVenus * 10 ^ 9) ) set OrbitalVelocityEarth sqrt ( ( ConstantG * MassSun ) / (TrueOrbitalRadiusEarth * 10 ^ 9) ) set OrbitalVelocityMars sqrt ( ( ConstantG * MassSun ) / (TrueOrbitalRadiusMars * 10 ^ 9) ) set OrbitalVelocityJupiter sqrt ( ( ConstantG * MassSun ) / (TrueOrbitalRadiusJupiter * 10 ^ 9) ) set OrbitalVelocitySaturn sqrt ( ( ConstantG * MassSun ) / (TrueOrbitalRadiusSaturn * 10 ^ 9) ) set OrbitalVelocityUranus sqrt ( ( ConstantG * MassSun ) / (TrueOrbitalRadiusUranus * 10 ^ 9) ) set OrbitalVelocityNeptune sqrt ( ( ConstantG * MassSun ) / (TrueOrbitalRadiusNeptune * 10 ^ 9) ) ; ; Initialize "Plot" orbital velocities set PlotOrbitalVelocityMercury OrbitalVelocityMercury set PlotOrbitalVelocityVenus OrbitalVelocityVenus set PlotOrbitalVelocityEarth OrbitalVelocityEarth set PlotOrbitalVelocityMars OrbitalVelocityMars set PlotOrbitalVelocityJupiter OrbitalVelocityJupiter set PlotOrbitalVelocitySaturn OrbitalVelocitySaturn set PlotOrbitalVelocityUranus OrbitalVelocityUranus set PlotOrbitalVelocityNeptune OrbitalVelocityNeptune ; ; Check to see if any planets have exceeded their minimum orbital velocities ; Set flag to plot zero orbital velocity if below threshold ; (Note: Each orbital velocity threshold is related to a corresponding centrifugal ; force threshold, which has reached a minimum necessary to hold the planet.) if (OrbitalVelocityMercury <= 46759) [set PlotOrbitalVelocityMercury 0] if (OrbitalVelocityVenus <= 34337) [set PlotOrbitalVelocityVenus 0] if (OrbitalVelocityEarth <= 29195) [set PlotOrbitalVelocityEarth 0] if (OrbitalVelocityMars <= 23729) [set PlotOrbitalVelocityMars 0] if (OrbitalVelocityJupiter <= 12872) [set PlotOrbitalVelocityJupiter 0] if (OrbitalVelocitySaturn <= 9524) [set PlotOrbitalVelocitySaturn 0] if (OrbitalVelocityUranus <= 6728) [set PlotOrbitalVelocityUranus 0] if (OrbitalVelocityNeptune <= 5386) [set PlotOrbitalVelocityNeptune 0] ; ; Configure for fast erase of orbit paths if (PlotOrbitalVelocityMercury = 0) [set OrbitalVelocityMercury 10 * OrbitalVelocityMercury] if (PlotOrbitalVelocityVenus = 0) [set OrbitalVelocityVenus 10 * OrbitalVelocityMercury] if (PlotOrbitalVelocityEarth = 0) [set OrbitalVelocityEarth 10 * OrbitalVelocityMercury] if (PlotOrbitalVelocityMars = 0) [set OrbitalVelocityMars 10 * OrbitalVelocityMercury] if (PlotOrbitalVelocityJupiter = 0) [set OrbitalVelocityJupiter 10 * OrbitalVelocityMercury] if (PlotOrbitalVelocitySaturn = 0) [set OrbitalVelocitySaturn 10 * OrbitalVelocityMercury] if (PlotOrbitalVelocityUranus = 0) [set OrbitalVelocityUranus 10 * OrbitalVelocityMercury] if (PlotOrbitalVelocityNeptune = 0) [set OrbitalVelocityNeptune 10 * OrbitalVelocityMercury] ; ; Calculate incremental degrees of rotation for each planet, for each update ; Incremental Degrees = 360 / ( orbital circumference / orbital velocity ) set IncDegreesMercury 360 / ((TrueOrbitalRadiusMercury * 10 ^ 9 * 2 * pi ) / OrbitalVelocityMercury) set IncDegreesVenus 360 / ((TrueOrbitalRadiusVenus * 10 ^ 9 * 2 * pi ) / OrbitalVelocityVenus) set IncDegreesEarth 360 / ((TrueOrbitalRadiusEarth * 10 ^ 9 * 2 * pi ) / OrbitalVelocityEarth) set IncDegreesMars 360 / ((TrueOrbitalRadiusMars * 10 ^ 9 * 2 * pi ) / OrbitalVelocityMars) set IncDegreesJupiter 360 / ((TrueOrbitalRadiusJupiter * 10 ^ 9 * 2 * pi ) / OrbitalVelocityJupiter) set IncDegreesSaturn 360 / ((TrueOrbitalRadiusSaturn * 10 ^ 9 * 2 * pi ) / OrbitalVelocitySaturn) set IncDegreesUranus 360 / ((TrueOrbitalRadiusUranus * 10 ^ 9 * 2 * pi ) / OrbitalVelocityUranus) set IncDegreesNeptune 360 / ((TrueOrbitalRadiusNeptune * 10 ^ 9 * 2 * pi ) / OrbitalVelocityNeptune) ; ; Maintain smooth orbital paths, while speeding-up the simulation, ; by decreasing the granularity of orbital graphs by a factor of 10^4 set IncDegreesMercury IncDegreesMercury * 10 ^ 4 set IncDegreesVenus IncDegreesVenus * 10 ^ 4 set IncDegreesEarth IncDegreesEarth * 10 ^ 4 set IncDegreesMars IncDegreesMars * 10 ^ 4 set IncDegreesJupiter IncDegreesJupiter * 10 ^ 4 set IncDegreesSaturn IncDegreesSaturn * 10 ^ 4 set IncDegreesUranus IncDegreesUranus * 10 ^ 4 set IncDegreesNeptune IncDegreesNeptune * 10 ^ 4 ; ; Calculate update position for each planet set DegreesMercury DegreesMercury + IncDegreesMercury set XCoordMercury DisplayOrbitalRadiusMercury * cos ( DegreesMercury ) set YCoordMercury DisplayOrbitalRadiusMercury * sin ( DegreesMercury ) set DegreesVenus DegreesVenus + IncDegreesVenus set XCoordVenus DisplayOrbitalRadiusVenus * cos ( DegreesVenus ) set YCoordVenus DisplayOrbitalRadiusVenus * sin ( DegreesVenus ) set DegreesEarth DegreesEarth + IncDegreesEarth set XCoordEarth DisplayOrbitalRadiusEarth * cos ( DegreesEarth ) set YCoordEarth DisplayOrbitalRadiusEarth * sin ( DegreesEarth ) set DegreesMars DegreesMars + IncDegreesMars set XCoordMars DisplayOrbitalRadiusMars * cos ( DegreesMars ) set YCoordMars DisplayOrbitalRadiusMars * sin ( DegreesMars ) set DegreesJupiter DegreesJupiter + IncDegreesJupiter set XCoordJupiter DisplayOrbitalRadiusJupiter * cos ( DegreesJupiter ) set YCoordJupiter DisplayOrbitalRadiusJupiter * sin ( DegreesJupiter ) set DegreesSaturn DegreesSaturn + IncDegreesSaturn set XCoordSaturn DisplayOrbitalRadiusSaturn * cos ( DegreesSaturn ) set YCoordSaturn DisplayOrbitalRadiusSaturn * sin ( DegreesSaturn ) set DegreesUranus DegreesUranus + IncDegreesUranus set XCoordUranus DisplayOrbitalRadiusUranus * cos ( DegreesUranus ) set YCoordUranus DisplayOrbitalRadiusUranus * sin ( DegreesUranus ) set DegreesNeptune DegreesNeptune + IncDegreesNeptune set XCoordNeptune DisplayOrbitalRadiusNeptune * cos ( DegreesNeptune ) set YCoordNeptune DisplayOrbitalRadiusNeptune * sin ( DegreesNeptune ) ; ; Update the position of each planet; erase orbits of ejected planets ifelse (PlotOrbitalVelocityMercury != 0) [ask turtle 1 [set xcor (max-pxcor / 1000) * XCoordMercury set ycor (max-pycor / 1000) * YCoordMercury]] [ask turtle 1 [set xcor (max-pxcor / 1000) * XCoordMercury set ycor (max-pycor / 1000) * YCoordMercury pen-down set pen-size 2 set color 0]] ifelse (PlotOrbitalVelocityVenus != 0) [ask turtle 2 [set xcor (max-pxcor / 1000) * XCoordVenus set ycor (max-pycor / 1000) * YCoordVenus]] [ask turtle 2 [set xcor (max-pxcor / 1000) * XCoordVenus set ycor (max-pycor / 1000) * YCoordVenus pen-down set pen-size 2 set color 0]] ifelse (PlotOrbitalVelocityEarth != 0) [ask turtle 3 [set xcor (max-pxcor / 1000) * XCoordEarth set ycor (max-pycor / 1000) * YCoordEarth]] [ask turtle 3 [set xcor (max-pxcor / 1000) * XCoordEarth set ycor (max-pycor / 1000) * YCoordEarth pen-down set pen-size 2 set color 0]] ifelse (PlotOrbitalVelocityMars != 0) [ask turtle 4 [set xcor (max-pxcor / 1000) * XCoordMars set ycor (max-pycor / 1000) * YCoordMars]] [ask turtle 4 [set xcor (max-pxcor / 1000) * XCoordMars set ycor (max-pycor / 1000) * YCoordMars pen-down set pen-size 2 set color 0]] ifelse (PlotOrbitalVelocityJupiter != 0) [ask turtle 5 [set xcor (max-pxcor / 1000) * XCoordJupiter set ycor (max-pycor / 1000) * YCoordJupiter]] [ask turtle 5 [set xcor (max-pxcor / 1000) * XCoordJupiter set ycor (max-pycor / 1000) * YCoordJupiter pen-down set pen-size 2 set color 0]] ifelse (PlotOrbitalVelocitySaturn != 0) [ask turtle 6 [set xcor (max-pxcor / 1000) * XCoordSaturn set ycor (max-pycor / 1000) * YCoordSaturn ]] [ask turtle 6 [set xcor (max-pxcor / 1000) * XCoordSaturn set ycor (max-pycor / 1000) * YCoordSaturn pen-down set pen-size 2 set color 0]] ifelse (PlotOrbitalVelocityUranus != 0) [ask turtle 7 [set xcor (max-pxcor / 1000) * XCoordUranus set ycor (max-pycor / 1000) * YCoordUranus]] [ask turtle 7 [set xcor (max-pxcor / 1000) * XCoordUranus set ycor (max-pycor / 1000) * YCoordUranus pen-down set pen-size 2 set color 0]] ifelse (PlotOrbitalVelocityNeptune != 0) [ask turtle 8 [set xcor (max-pxcor / 1000) * XCoordNeptune set ycor (max-pycor / 1000) * YCoordNeptune]] [ask turtle 8 [set xcor (max-pxcor / 1000) * XCoordNeptune set ycor (max-pycor / 1000) * YCoordNeptune pen-down set pen-size 2 set color 0]] ; ] ; end of one present-day Earth-year revolution ; ; Increment counter of Earth-years, if Mercury is still orbiting if(PlotOrbitalVelocityMercury != 0) [set EarthYearsCounter EarthYearsCounter + 1] ; ; Update plot update-plot ; ; Check for pause if Pause [ stop ] ; Erase final planet, Mercury, orbit ; and stop once all eight planets have left the Solar System if(PlotOrbitalVelocityMercury = 0) [set LastPlanetErase LastPlanetErase + 1] if(LastPlanetErase > 1) [stop] ; ] ; end of loop ; end to setup-plot set-current-plot "Orbital Velocities" set-plot-x-range 0 100 set-plot-y-range 0 100 end to update-plot ; Plot Sun mass percentage, scaled x 1000 set-current-plot-pen "%Sunx1000" plot (MassSun / OriginalMassSun * 100) * 1000 ; Plot planet velocities in km/s set-current-plot-pen "Mercury" plot PlotOrbitalVelocityMercury set-current-plot-pen "Venus" plot PlotOrbitalVelocityVenus set-current-plot-pen "Earth" plot PlotOrbitalVelocityEarth set-current-plot-pen "Mars" plot PlotOrbitalVelocityMars set-current-plot-pen "Jupiter" plot PlotOrbitalVelocityJupiter set-current-plot-pen "Saturn" plot PlotOrbitalVelocitySaturn set-current-plot-pen "Uranus" plot PlotOrbitalVelocityUranus set-current-plot-pen "Neptune" plot PlotOrbitalVelocityNeptune end @#$#@#$#@ GRAPHICS-WINDOW 451 74 1073 717 32 32 9.42 1 10 1 1 1 0 0 0 1 -32 32 -32 32 0 0 1 ticks BUTTON 154 155 280 226 Rotate Planets RotatePlanets NIL 1 T OBSERVER NIL NIL NIL NIL BUTTON 133 76 300 138 Create Solar System Setup NIL 1 T OBSERVER NIL NIL NIL NIL SLIDER 118 259 337 292 AnnualSunMassLossPercent AnnualSunMassLossPercent 0 2 0.01 0.01 1 NIL HORIZONTAL PLOT 12 321 440 631 Orbital Velocities Time (Earth-Years) Velocity (m/s) 0.0 10.0 0.0 10.0 true true PENS "Mercury" 1.0 0 -3844592 true "Venus" 1.0 0 -6459832 true "Earth" 1.0 0 -15637942 true "Mars" 1.0 0 -2674135 true "Jupiter" 1.0 0 -10402772 true "Saturn" 1.0 0 -5825686 true "Uranus" 1.0 0 -13791810 true "Neptune" 1.0 0 -11783835 true "%Sunx1000" 1.0 2 -4079321 true MONITOR 166 655 296 708 Earth-Years Counter EarthYearsCounter 0 1 13 SWITCH 453 29 556 62 Pause Pause 1 1 -1000 @#$#@#$#@ WHAT IS IT? ----------- This is a model for the eventual demise of our Solar System. Our Solar System is held in place by a delicate balance of opposing centripetal and centrifugal forces. As our Sun generates energy by fusing its hydrogen, its loss of mass reduces the centripetal force, necessitating a reduction in the centrifugal force, as manifested by reduced orbital velocities for each of the planets. As each planet’s orbital velocity falls below a threshold, it is ejected from the Solar System. When all of the planets have left the confines of the Sun, our Solar System ceases to exist. HOW IT WORKS ------------ Each Earth-year, the Sun's mass is updated based on the selected annual percentage mass loss. The (slower) orbital velocity for each of the planets is updated based on the Sun's new mass. Planets whose orbital velocities have fallen below their thresholds are erased from the view. HOW TO USE IT ------------- The user: (1) selects an annual percentage mass loss for the Sun using a "slider", (2) creates the Solar System by pressing a "button", (3) sets the Solar system in motion, toward its demise, by pressing a second "button". and (4) when all of the planets have ejected, the simulation halts, with the final elapsed time in Earth-years displayed on a "monitor". It is recommended that the user select an annual percentage of Sun mass loss in the range from 0.01% to 1.0%. Higher values execute instantaneously; lower values execute in excessive amounts of time. THINGS TO NOTICE ---------------- Three windows in the view provide real-time data on the progress of the simulation: 1. The main window shows the Solar System, with progressively shrink Sun and slowing and ejecting planets. 2. A "moniter" counts the passage of time in Earth-years. 3. A "plot" graphs the declining Sun mass and decreasing orbital velocities. THINGS TO TRY ------------- 1. Set the "Pause" slider to on, press the "Create Solar System" button, and then press the "Rotate Planets" button to see the relative orbital velocities portrayed, after the Earth completes one revolution. 2. Set the "AnnualSunMassLossPercent" slider to different values and engage the simulation, to observe the relationship between the rate at which the Sun loses mass, and the number of years remaining for our Solar System. 3. Set the "AnnualSunMassLossPercent" slider to an initial value, engage the simulation, and change the sliders value during execution (faster or slower) to observe non-linear relationships between the rate at which the Sun loses mass, and the number of years remaining for our Solar System. EXTENDING THE MODEL ------------------- 1. Add the terminal special effects of the Sun’s gaseous radius extending beyond the inner planets, in the final millions of years, to create a hybrid theoretical view of the end of the Solar System. 2. Conduct simulation experiments with non-linear rates of annual Sun mass loss, and observe the effects on Solar System longevities. 3. Learn or develop some physics for the selection of the orbital velocity ejection thresholds, and incorporate that knowledge into the model. NETLOGO FEATURES ---------------- Standard. RELATED MODELS -------------- None. CREDITS AND REFERENCES ---------------------- Created by Toby Skinner, at Portland State University, for CS-346, Fall 2011. @#$#@#$#@ default true 0 Polygon -7500403 true true 150 5 40 250 150 205 260 250 airplane true 0 Polygon -7500403 true true 150 0 135 15 120 60 120 105 15 165 15 195 120 180 135 240 105 270 120 285 150 270 180 285 210 270 165 240 180 180 285 195 285 165 180 105 180 60 165 15 arrow true 0 Polygon -7500403 true true 150 0 0 150 105 150 105 293 195 293 195 150 300 150 box false 0 Polygon -7500403 true true 150 285 285 225 285 75 150 135 Polygon -7500403 true true 150 135 15 75 150 15 285 75 Polygon -7500403 true true 15 75 15 225 150 285 150 135 Line -16777216 false 150 285 150 135 Line -16777216 false 150 135 15 75 Line -16777216 false 150 135 285 75 bug true 0 Circle -7500403 true true 96 182 108 Circle -7500403 true true 110 127 80 Circle -7500403 true true 110 75 80 Line -7500403 true 150 100 80 30 Line -7500403 true 150 100 220 30 butterfly true 0 Polygon 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