diff --git a/sim_scenes/science/sun_earth_moon.py b/sim_scenes/science/sun_earth_moon.py
index 7c9df3257ca78ae9d7f27545e0aa35aa684cd038..697cca2b33ec204688d64c8caed345751c00d62f 100644
--- a/sim_scenes/science/sun_earth_moon.py
+++ b/sim_scenes/science/sun_earth_moon.py
@@ -48,6 +48,8 @@ if __name__ == '__main__':
 
         # 1个月有29.5天
         days_per_month = 29.5
+        # TODO: 月绕地公转周期为 27.3 天，两次到日地延长线的时间间隔才是29.5天
+        # days_per_month = 27.3
         # 1天多少角度
         angle_per_day = 360 / days_per_month
         # 当前天数的角度（度）