As you know, the comet’s tail is directed away from the Sun. Therefore, if a comet suddenly finds itself between the Sun and the Earth, and its tail is long and bright enough, its apparent length in the sky will reach 180 °. In this case, the tail will extend from the Sun to the anti-sun point of the sky. Of course, in this case the comet itself will be in conjunction with the Sun and will not be visible. A comet located at an angular distance d from the Sun, the tail length can reach 180 ° -d. The last time a comet with a tail of about 100 ° was observed was in 1996 (comet Hyakutake).
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.