earthOrbit.add( earthMesh );
	objects.push( earthMesh );

	const moonOrbit = new THREE.Object3D();
	moonOrbit.position.x = 2;
	earthOrbit.add( moonOrbit );

	const moonMaterial = new THREE.MeshPhongMaterial( { color: 0x888888, emissive: 0x222222 } );
	const moonMesh = new THREE.Mesh( sphereGeometry, moonMaterial );
	moonMesh.scale.set( .5, .5, .5 );
	moonOrbit.add( moonMesh );
	objects.push( moonMesh );

	// add an AxesHelper to each node
	objects.forEach( ( node ) => {

		const axes = new THREE.AxesHelper(