The Sweep of Time

Interesting column by Bob Berman in this month's 'Astronomy' magazine. Well, all of his columns are well done but this one got me thinking. The column is here but you have to be a subscriber to see the whole thing. He talks about certain periodic night time events and how some of them are only a few to a life time. Excerpt:

Great comets are in this category, too. In the past 40 years, the only ones that stood out over cities were Bennett in 1970, West in 1976, Hyakutake and Hale-Bopp in 1996 and 1997, respectively, and McNaught in 2007, though this latter comet was largely seen by Aussies and penguins. From the United States, most people saw only Hale-Bopp. Halley’s Comet had its worst showing since the Roman Empire when it came by in 1985. It will atone 50 years from now, in 2061. Eat those veggies.

Halley's Comet has a special place in astronomical lore. It's one of the few things up there that a) most people know about and b) isn't a planet or the sun. It was the first comet that we realized appeared on a regular basis. Way back in 1705 Edmond Halley figured out that past great comets were all the same big snowball and predicted another return in 1758. He was (mostly) right and another big chunk of understanding was added to the human total. This list of past appearances is pretty interesting.
The thing about Halley's Comet is that it's 75/76 year period is close to the expected human lifespan. Most people will only get a chance to see it once. The next appearance is due 50 years from now. That would put me at 87 years old. Not impossible but far from certain.
What struck me is that this will probably be Relia and DF's only chance of seeing it. They'll both be in their young 50's. I'm somewhat hopeful that their father's enthusiasm for astronomy will translate for the two of them; certainly enough that they'll find some time to trudge out to some dark sky field and look at an historic event.