If you stare at sun at the twelve o'clock in the noon, this time the sun light will be the most strongest. Even with your eyes closed, the sun light will still penetrate through your eyelids and do harm to your eyes. So, please don't do like this from the time ten o'clock in the morning till two o'clock in the afternoon. For the sunrise and the setting sun, you can close your eye or even open your eyes for view. If you want to stare at the bright sunlight, you could adopt a goggle to protect your eyes.
No, it's more dangerous. As we all known, the sunlight is beneficial for people's health, including produce vitamin D and improve mood. However, the intensity of direct sunlight could make damage to your eyes when you close your eyes. The eyelid could provide inadequate protection from the sun due to it's only composed of a thin layer of tissue. And the retina is sensitive to light and can be damaged by prolonged exposure to light. Hence, wearing a pair of sunglasses with anti-UV rays' functionality is always recommended in sunny days.
Generally speaking, staring at the sun greatly damages your vision because of its super intensity. And sun beams will do tremendous harm to your pupil, even if your eyes are closed. So, for your benefits, please do not try out of curiosity. Anyway, curiosity is a source of danger, sometimes.
It is not safe to stare at the sun with the eyes closed. Even if the eyes are closed, the strong sunshine may illuminated through your skin into the eyes which may not only damage the pupils but also hurt the skin. Thus, you'd better not do this. In order to protect your eyes, you just avoid the direct strong sunshine.
No, it's dangerous to stare at the sun with your eyes closed. Many people say that exposure to sunlight has a number of health benefits including vitamin D production and improved mood. But on the other hand, the intensity of direct sunlight can do great damage to your eyes even when your eyes are closed. I suggest that you should always wear sunscreen on your skin and control your sun exposure. Only in this way, can you not damage your skin with harmful UV rays. Besides, you should also wear sunglasses which can protect your eyes from UV rays. Your eyes are protected from the damaging effects of the sun.