Games [XUI2D] How to make a rotating circle rotate in circle

Public Sub Start
    X2.Reset
    TileMap.Initialize(X2, File.DirAssets, "hello world with background.json", Null)
    TileMap.SetSingleTileDimensionsInMeters(X2.ScreenAABB.Width / TileMap.TilesPerRow, X2.ScreenAABB.Height / TileMap.TilesPerColumn)
    TileMap.PrepareObjectsDef(ObjectLayer)
    Earth = TileMap.CreateObject2ByName(ObjectLayer, "earth")
    Sun = TileMap.CreateObject2ByName(ObjectLayer, "sun")
    Earth.Body.ApplyForceToCenter(X2.CreateVec2(0, 30))
    Earth.Body.AngularVelocity = 3
    Dim v As B2Vec2 = Earth.Body.Position.CreateCopy
    v.SubtractFromThis(Sun.Body.Position)
    Dim rope As B2RopeJointDef
    rope.Initialize(Sun.Body, Earth.Body, X2.CreateVec2(0, 0), X2.CreateVec2(0, 0), v.Length)
    world.CreateJoint(rope)
    X2.Start
End Sub