When it comes to life on other planets, I can’t help but wonder how they would perceive a solstice on their own planet. Does being highly sentient imply being inclined to seek patterns and search for meaning and reasons behind those patterns? If that is the case, then these sentient beings would likely view solstices and equinoxes in the same way our ancient ancestors did (even prior to the existence of Stonehenge).
They would attempt to assign a purpose or reason to these patterns, as finding meaning or reason allows for predictions and a sense of control (or at least the illusion/delusion of control). Of course, this perspective depends on several factors that influence the severity or tranquility of annual weather patterns.
Does the planet follow a highly circular orbit or a more elliptical one? Is the planet located close to its star, resulting in a short year? Could it possibly be a large habitable moon orbiting a gas giant? Does the planet exhibit minimal axial tilt or a substantial one? Or perhaps a combination of these factors? However, I must make an assumption here.
While humans have always shown a keen interest in marking solstices and equinoxes since prehistoric times, an alien mind may not attach any particular theological or symbolic significance to such cyclical patterns. Solstices may hold no importance for them, and they might be puzzled by the importance we place upon them.
If they possess a religious inclination, their religious beliefs might lead them to focus on other patterns that they deem special and noteworthy. Perhaps they celebrate the birth of their god in the middle of Spring, between solstices or equinoxes.
Maybe their sun holds no significance to them (such as in the case of a blind species or a species that thrives beneath the ice, relying on thermal vents rather than the sun for energy, or even a subterranean species…). It is even possible that they have two or three suns, which would make their special days more complex and infrequent.
Another question is: if there is one God, surely He would be interested in all of His spiritual children (“other children have I…”)), and if so, would He then visit other planets? How would He visit them? Would we recognize that He did in their religious texts and stories?