A major theme of the blog in the last week has been forecast uncertainty. Where, we wondered repeatedly, would Hurricane Dean go? How strong would it get? Which computer prediction should we trust? Needless to say, forecasting the future is a tricky business, even with the most advanced computer models. But there are some things that are a bit easier to model. For instance, I can make a forecast for ten years from today, and guarantee you with near-absolute certainty that it will come true:

On August 21, 2017, at precisely 10:15 AM and 50 seconds PDT, something will make landfall on the coast of Oregon, just north of the town of Newport. It will proceed across the country on an ESE to southeasterly course, crossing the Grand Teton National Park in Wyoming, Kansas City and St. Louis in Missouri, Nashville and West Knoxville in Tennessee — including our current apartment — and Charleston in South Carolina, before finally touching down in the Atlantic Ocean and leaving dry land behind at 2:49:07 PM EDT off Cape Romain, SC.

What is this “something” I speak of? Not a hurricane, nor any other kind of weather system, but the shadow of the Moon!

That’s right: ten years from today, the continental United States will experience its first total solar eclipse in the lifetime of many of this blog’s readers. Not since 1979 has this most amazing of astronomical events been visible from anywhere in the Lower 48. (Some of you may remember seeing a solar eclipse in 1994, but that one was annular, not total.)

Here is a cool narration of the journey that the Moon’s umbra — i.e., its inner shadow, the small area where the Sun is completely obscured — will take across the country, from coast to coast. And here are a bunch of maps. You can also view the maps on Google Maps or Google Earth.

The eclipse can be viewed from a much wider area — all of North America, in fact, and part of South America — as a partial eclipse. But only in that narrow strip with the eclipse be total. And that makes all the difference in the world. Partial eclipses are awesome, but total eclipse are about a thousand times more awesome, because with a total eclipse, day truly turns to night during the totality phase — and you can actually look directly at the sun, since none of the photosphere (the part whose rays can damage your retinas) is visible. (You must NEVER look directly at the Sun during a partial or annular eclipse, or the partial phase of a total eclipse, no matter how small the sliver of visible photosphere is. Only during totality is direct viewing safe!)

Here’s a broader map showing the penumbral path (where the eclipse is partial) as well as the umbral path. And below it is an animated GIF showing the same thing; the small, fast-moving black dot represents the umbral shadow (i.e., the path of totality). Both images are courtesy of eclipse.org.uk.

As regular readers know, the eclipse has long been on my countdown sidebar at left — 3,653 days and counting! :) Ten years is a long time, but I’m already actively looking forward to this event. You have to understand: total eclipses are unlike anything else in astronomy, or the human experience for that matter. People who’ve seen one (or more) consistently describe them as life-changing experiences.

I’m fully committed to being somewhere along the path of totality on August 21, 2017, regardless of where Becky, the kid(s) and I are living at that point. I’ll apply for time off work years in advance if I have to. :) And we won’t be alone: a few months ago, I told some of the SHA girls about the eclipse, and we made a pact that, wherever we’re living in 2017, we will get together to watch the eclipse. If Becky and I still in Knoxville, we’ll probably get together here, but if not, I’m thinking maybe Grand Teton, since the weather probably stands a pretty good chance of being good there. Of course, wherever we pick, I’ll be obsessively checking the weather in the days before the eclipse, ready to resort to Plan B and Plan C in either direction along the path of totality if necessary. :)

Interestingly enough, although 2017 is the first eclipse in a long time, it won’t be the last for a long time. There will be another total eclipse on April 8, 2024, trekking diagonally across the country in essentially the opposite direction, from southwest to northeast. Among other places, that one goes right through Buffalo. And if you happen to live in the Carbondale, Illinois region (home of the Salukis!), you get the unique experience of having two total solar eclipses in seven years! Here’s a map of the overlapping paths of totality:

Anyway… I don’t know if I’ll still have a blog in ten years, but if I do, I promise to provide complete blog coverage of the eclipse. :)

P.S. I say “near-absolute certainty” because there are various hypothetically possible events, each of which has a negligible but nonzero probability of occurring, that could disrupt the eclipse. For example: the Sun could go nova. It’d be several billion years early, but hey, it coudl happen. Or a large, heretofore undetected asteroid could impact either the Earth or the Moon and the impacted body’s orbit. Or some larger galactic event could mess up both orbits. Or we could all be sucked into a black hole. Or Frank J. could succeed in his efforts to Nuke the Moon. :)

P.P.S. West Town Mall, which is just up the road from where Becky and I live, will quite literally be the northern border of the path of totality:

Of course, one doesn’t want to watch the eclipse from the very edge of the path of totality, because the eclipse is only total for a few seconds there — not even enough time to take off your protective glasses! Instead, you want to head for someplace along the “center line,” where totality will last for more than two minutes. Like for instance, the Sweetwater, TN area…

…or better yet, as I mentioned, Grand Teton: