Predicting the exact timing and characteristics of future comets is challenging, as they are highly unpredictable celestial objects. The appearance of a "great" comet, comparable to or rivaling Hale-Bopp in terms of brightness and visibility, cannot be accurately determined in advance.
Hale-Bopp, a notable comet that made a highly visible appearance in 1997, was considered a rare event due to its large size, bright coma, and long duration of visibility. While it is possible for future comets to exhibit similar characteristics, there is no certainty or specific timeline for when the next great comet will arrive.
Discovering and predicting comets typically relies on advanced telescopes and astronomical surveys that monitor the sky for celestial objects. Astronomers continuously observe the skies in search of comets, and they often provide estimates and predictions based on their observations and calculations. However, comets can still surprise us with unexpected brightness or dimness, and their behavior is influenced by various factors, such as their composition, orbit, and interactions with the Sun.
Therefore, while we can anticipate the occurrence of comets in the future, it is difficult to predict when the next great comet will appear or whether it will rival the visibility of Hale-Bopp. Continued advancements in astronomical observations and surveys will contribute to our understanding and detection of comets, but the specifics of individual comets remain uncertain until they are observed and studied.