During my half century on Earth, two summers really stand out as magical: 1987 and 2000. And given recent events, surely we are all about due for another exceptional summer! It turns out summer 2017 could be that very season. Because near its end, a scant few days before Labor Day, there will be the grandest spectacle the sky can provide as a total solar eclipse cuts a diagonal swath across the U.S., moving from sea to shining sea on August 21. The image above shows that everyone in the lower 48 will get to see a serious partial eclipse. And it looks like just a little traveling will carry millions into one of those zones of precious totality. They say the difference between a total and partial solar eclipse is … well, fill in the blank yourself!
The last time I saw a really good eclipse was so long ago it’s mostly grayed out by early childhood. I was barely in grade school back in 1970, in the Bluegrass State, when the total eclipse region cut a line up the east coast from Florida through DC, all the way to Maine. But after all those years, I still remember the actual eclipse: around noon, with the sun blazing overhead on a warm, clear March day, it started getting dim and the world grew still, almost deathly quiet. We ran back and forth between looking at the event using the pinhole technique and watching it on TV. From Kentucky, the eclipse was about an 85 to 90 percent event.
But this one—this one—will cruise the entire U.S. as a full and total solar eclipse, an extremely rare event all around. There’s an interactive tool here. Other than that, come below the fold and learn just how rare it is, and when it will be coming to a sky near you.
Total solar eclipses are so rare because the moon’s apparent diameter is, on average, just a tiny bit smaller than the sun’s width in the sky. But the Earth doesn’t go in a perfect circle around the sun, and the moon doesn’t travel in a perfect circle around the Earth. Between the two there are times when the moon’s apparent diameter is a tiny bit wider than the sun’s. And every now and then those positions happen when the moon is directly in between the sun and the Earth.
At other times, when the moon grazes the sun or when the moon manages to get right in front of it but is slightly smaller in the sky than the sun, we get a partial eclipse or an annular eclipse, respectively. Those are both still really neat to behold, but a total solar eclipse is unlike either of them.
The moon so perfectly occludes the sun when all three bodies are properly lined up that the solar corona becomes instantly and completely visible. A flaming halo hanging in the sky, ringing a pitch black hole, is so dramatic and so rare that ancient people had to think the world might be coming to an end. Total solar eclipses are still so rare that getting a good, clear one on the photographic record in the early 20th century held up one of the most important verifications of Einstein’s General Theory of Relativity for years and years.
It’s rarer still for such an event to traverse a continent as wide as North America, but that’s what will happen starting in about 11 weeks. It will start just before and after noon, depending on your time zone, about as prime as it could be. I’ve tried to be careful in translating the estimated UTC times below to their local analogues, but use the guidelines at your risk.
The eclipse will begin to become noticeable at just before 11 AM local time (UTC 15:46) in the Pacific Northwest. The path of the eclipse is moving east while the sun of course is moving from east to west. About one hour later the path of totality will make landfall on the west coast near Salem, Oregon. Over the next two hours it will race over Idaho, Wyoming, and Nebraska. It will graze St. Louis, pass right over Kansas City, then arc down toward Nashville and western Kentucky. It will end over both Carolinas at around the 2 PM EST, and head out to sea off the coast of Hilton Head. That’s quite a tour!
Are you planning to try and be in one of the total eclipse regions? Weather is always a gamble and the high desert of Wyoming is considered one of the more reliable places for clear skies. The midwest is a crapshoot and the lower eastern seaboard could be beautiful or in the crosshairs of a tropical storm at that time of year.
In fact I might just be traveling that weekend, specifically to see this. Because everyone should see a total solar eclipse at least once in their lives.
Come to think of it, I’m pretty sure Mark Sumner lives near one of the Missouri sites …