Ok folks, this is it. If you missed the Transit of Venus in June, 2004 then today, June 5, 2012 is the last time you will see this rare astronomical event until December 2117!
For some reason, we all seem to enjoy celestial spectacles, whether they are a total solar eclipse or an occasional spectacular comet the lights up the night sky. When "planetary alignments" happen, we marvel at our prowess in being able to predict them, and then go out and gawk at them right on schedule. When the planet Venus passes between the sun and Earth in exactly the right way, everything lines up and you see a small black dot travel majestically across Old Sol's face. The one we will see today was first predicted by long-gone astronomers over 150 years ago. The mathematical precision of this orbital dance let them wonder about the amazing science that would welcome us when the "flowers next bloomed in June of 2004." So here we are, with the 2004 transit behind us and the last one of this pair about to occur. None of us living today will see the next one, and for me there is something creepy about that realization.
The thing that I love about being an astronomer is that I get to study things that have nothing to do with people, or the day-to-day crises that we have to deal with. As I was doing 15 TV spots this morning for stations across the country, I got snippets of local news being reported just before the slated Transit of Venus segment. It was very surreal! While I was composing my thoughts about the transit, my earpiece was letting me eavesdrop-in on news reports about murders, violence, robbery and other lighter stories too, like the dear that ran through a store in Denver. Then I had to answer a handful of questions about why the transit is important, how to watch it and what NASA scientists will learn from it.
The next time a human sees the black dot of Venus in transit, I can't begin to imagine what kind of society that will be, or the technological circumstances that will prevail then. None of the things we take for granted today were even imagined back in 1882 when astronomer William Harkness penned the quote about the flowers blooming in 2004. As you watch this transit, either in person or through the many web-based video streams, think about those future observers in 2117 and what might be on their minds. Those of us who remember the 1960s recall a 21st Century with flying cars and nuclear power plants in every home, but there was no hint of personal computers and the Internet on the horizon. Will we still worry about our employment, food, the environment and wars? Probably. But I wonder: what will be the background technologies and scientific advancements that the denizens of 2117 will utterly take for granted? Will western society suffer a major crash, taking us back to a life reminiscent of the early-1900s, or will we still be on an upward climb towards greater prosperity, better health and even more fun discoveries in science?
No matter what the prospects will be, the planets in their predictable movements will afford us a steady stream of new spectacles to come, which are sure to entertain and amaze us. On July 28, 2061 we have the return of Halley's Comet. On November 22, 2065 you will be able to see the planet Venus pass across the planet Jupiter. Then on August 11, 2079 Mercury will do the same thing to the planet Mars. But my favorite celestial event is the November 10, 2084 transit of Earth across the face of the sun as viewed from the surface of mars! We might hope that an actual human will be standing on mars to watch this event, which we know about today in all kinds of lovely mathematical detail. But even if a human is not involved, you can be sure that one of several robotic rovers will pause in its labors for just a few minutes. It will point its telescope at the sun and send us a pretty picture of this "cosmic" moment. The far future of 2117 may seem incomprehensible to us today, but 2084 is no more remote from us than 1940 is from us today. Many things have changed, for sure, but much remains more or less as it was back then!