crank wrote:It's kinda surprising this only happens about every 7 years when you think about how far away we are and how big the sun is, plus mercury 's year is about 3 months. If someone asked me how often this would occur, I would have guessed way higher, maybe more than once a year. So my thinking has mercury too close [to the sun] with less difference in inclination.
It's the orbital inclination that makes this a relatively rare event. If there were no difference in inclinations, it would happen about 4 times per year.
Much less rare, though, than Venus, which sees a pair of transits 8 years apart then a gap of either ~ 105 or 121 years before the next pair.
I'm pretty happy having seen this one - since I moved back home after retiring from the Army, I've seen two astronomical transits of the Sun from my home town, and looking forward to seeing another in 2024, when I'll only have to travel a short distance (like about 15 miles) to be on the main track of a total solar eclipse.