private void SimulateWithBarnesHut()
    {
        quadtree.Clear();
        quadtree.TryAddRange(planets);

        if (!IntegrateMovement)
        {
            return;
        }

        foreach (PlanetController planet in planets)
        {
            planet.Acceleration =
                quadtree.CalculateForce(
                    planet, CalculateNewtonGravityAcceleration
                    );
        }
    }