the answer is moon. the name tells you what you can't see. since in a solar eclipse you can't see the sun that means that the moon is in between us on earth and the sun. which is why we can't see it
The vessels use three main colors (white, green and red) where each color alone, combination of two colors as well as the three colors together each has a certain meaning. This meaning is sort of an international code that is agreed all over the globe.
So, based on this code, the presence of only visible white light means that your vessel might be overtaking another vessel. In this case, you should give way to either sides. The other vessel should standby until an action is taken from your end.
