               lastEarthDayUpdate = now;
            }
        }

        // 绘制场景
        function drawScene() {
            const centerX = canvas.width / 2;
            const centerY = canvas.height / 2;

            // 清除画布
            ctx.clearRect(0, 0, canvas.width, canvas.height);

            // 绘制轨道
            ctx.drawImage(orbitCanvas, 0, 0);

            // 绘制太阳和行星
            planets.forEach(planet => {
                let x, y;

                if (planet.