Today begins a nearly once in a lifetime event.  Something magnificent, epic and (literally) astronomical.  A tiny dot will pass in front of the sun.

Venus begins its transit on June 8, 2004.

To most, this may seem, well, boring.  But this dot is so much more than just a dot.  It’s an entire planet.  Venus, in fact.  It’s something that exists over 40 million km (over 25 million miles) from Earth…that you can see with your own eyes!  By watching this small silhouette, scientists hundreds of years ago were able to calculate just how far away we are from the sun.  So what does this mean for you?  Adam Frank, an astrophysicist at the University of Rochester and co-author of the NPR.org blog 13.7: Cosmos and Culture, explained in much better words than myself:

The next Venus transit will be in 2117. That is 105 years from now. It’s unlikely that anyone reading this today will still exist then. Think about that: The next time the orbits of Earth and Venus align just so to create a transit, the world will be entirely populated by an entirely unborn generation. That essential point about time is really what makes this transit worth a moment of your own.

It’s rare for us to get pulled over the narrow time horizons defining our lives. We struggle through the daily cycle of waking and work, looking to the longer cycle of weekends for some rest. On even longer time scales we make appointments or plan vacations months in advance. We may even think on yearlong cycles dreaming of that summer home we want to buy. But short of worrying about retirement (but not doing much about it), the time horizon of our lives never stretches further than a few years.

Then along comes a celestial event like the Venus transit announcing, “This won’t happen again for 105 years”. It comes as a kind of shock, and we have no experience with this kind of time scale. It’s not like our favorite TV shows disappear for centuries. “Oh, by the way, Game of Thrones will be back on in 2125.” These long time horizons are not easy for human beings to digest, but their recognition is essential piece of our evolution in both science and civilization.

And that’s the point.

This was a chunk out of the middle of Dr. Frank’s post “The Venus Transit: Who Cares?“, which I encourage you to read in it’s entirety (by following the link, obviously).  The point is, visually, it’s not much more than that small dot.  One that takes some effort to even see considering you must take some precautions when looking directly at the sun…lest you intend to go blind (or at least suffer permanent eye damage).  But the meaning behind it, the idea behind what you are looking at is (at least to me)  mind-blowing.

I’d end this post there, but I feel it necessary admit that this isn’t quite a once in a lifetime event.  The Venus Transit occurs in pairs, separated by 8 years (the first of this pair happened on June 8, 2004), with pairs of transits separated by over 100 years…last was December 6, 1882 and  the next won’t be until December 11, 2117.  BUT, if you are like me and somehow completely missed all mention of the transit in 2004, this is you last chance!

Also, I feel it obligatory to direct you to a good resource for how to safely view the transit.  Phil Plait (aka The Bad Astronomer) of discovermagazine.com blog Bad Astronomy has been posting like a mad man about the transit and has collected a great set of viewing tips and websites with even more suggestions (including live web cams!).  You can find this and much more in his post: Everything you need to know about next week’s Transit of Venus (written last week, of course).