Astronomy Animation¶

Object-oriented programming¶

import turtle
import math

class SolarSystem:

def __init__(self, width, height):
        self.thesun = None
        self.planets = []
        self.ssturtle = turtle.Turtle()
        self.ssturtle.hideturtle()
        self.ssscreen = turtle.Screen()
        self.ssscreen.setworldcoordinates(-width/2.0,-height/2.0,width/2.0,height/2.0)
       # self.ssscreen.tracer(50)

def addPlanet(self, aplanet):
        self.planets.append(aplanet)

def addSun(self, asun):
        self.thesun = asun

def showPlanets(self):
        for aplanet in self.planets:
            print(aplanet)

def freeze(self):
        self.ssscreen.exitonclick()

def movePlanets(self):
        G = .1
        dt = .001

for p in self.planets:
           p.moveTo(p.getXPos() + dt * p.getXVel(), p.getYPos() + dt * p.getYVel())

rx = self.thesun.getXPos() - p.getXPos()
           ry = self.thesun.getYPos() - p.getYPos()
           r = math.sqrt(rx**2 + ry**2)

accx = G * self.thesun.getMass()*rx/r**3
           accy = G * self.thesun.getMass()*ry/r**3

p.setXVel(p.getXVel() + dt * accx)

p.setYVel(p.getYVel() + dt * accy)

class Sun:
   def __init__(self, iname, irad, im, itemp):
       self.name = iname
       self.radius = irad
       self.mass = im
       self.temp = itemp
       self.x = 0
       self.y = 0

self.sturtle = turtle.Turtle()
       self.sturtle.shape("circle")
       self.sturtle.color("yellow")

def getName(self):
       return self.name

def getRadius(self):
       return self.radius

def getMass(self):
       return self.mass

def getTemperature(self):
       return self.temp

def getVolume(self):
       v = 4.0/3 * math.pi * self.radius**3
       return v

def getSurfaceArea(self):
       sa = 4.0 * math.pi * self.radius**2
       return sa

def getDensity(self):
       d = self.mass / self.getVolume()
       return d

def setName(self, newname):
       self.name = newname

def __str__(self):
       return self.name

def getXPos(self):
       return self.x

def getYPos(self):
       return self.y

class Planet:

def __init__(self, iname, irad, im, idist, ivx, ivy, ic):
       self.name = iname
       self.radius = irad
       self.mass = im
       self.distance = idist
       self.x = idist
       self.y = 0
       self.velx = ivx
       self.vely = ivy
       self.color = ic

self.pturtle = turtle.Turtle()
       #self.pturtle.speed('fast')
       self.pturtle.up()
       self.pturtle.color(self.color)
       self.pturtle.shape("circle")
       self.pturtle.goto(self.x,self.y)
       self.pturtle.down()

def getName(self):
       return self.name

def getRadius(self):
       return self.radius

def getMass(self):
       return self.mass

def getDistance(self):
       return self.distance

def getVolume(self):
       v = 4.0/3 * math.pi * self.radius**3
       return v

def getSurfaceArea(self):
       sa = 4.0 * math.pi * self.radius**2
       return sa

def getDensity(self):
       d = self.mass / self.getVolume()
       return d

def setName(self, newname):
       self.name = newname

def show(self):
        print(self.name)

def __str__(self):
       return self.name

def moveTo(self, newx, newy):
       self.x = newx
       self.y = newy
       self.pturtle.goto(newx, newy)

def getXPos(self):
       return self.x

def getYPos(self):
       return self.y

def getXVel(self):
       return self.velx

def getYVel(self):
       return self.vely

def setXVel(self, newvx):
       self.velx = newvx

def setYVel(self, newvy):
       self.vely = newvy

def createSSandAnimate():
   ss = SolarSystem(2,2)

sun = Sun("SUN", 5000, 10, 5800)
   ss.addSun(sun)

m = Planet("MERCURY", 19.5, 1000, .25, 0, 2, "blue")
   ss.addPlanet(m)

m = Planet("EARTH", 47.5, 5000, 0.3, 0, 2.0, "green")
   ss.addPlanet(m)

m = Planet("MARS", 50, 9000, 0.5, 0, 1.63, "red")
   ss.addPlanet(m)

m = Planet("JUPITER", 100, 49000, 0.7, 0, 1, "black")
   ss.addPlanet(m)

m = Planet("Pluto", 1, 500, 0.9, 0, .5, "orange")
   ss.addPlanet(m)

m = Planet("Asteroid", 1, 500, 1.0, 0, .75, "cyan")
   ss.addPlanet(m)

numTimePeriods = 10000
   for amove in range(numTimePeriods):
        ss.movePlanets()

ss.freeze()

createSSandAnimate()

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