"The Constant Eclipse"

When the total solar eclipse visits the US this August 21st, the whole experience will last about three hours. Here in Columbus the party starts around 1pm, when the disk of the moon begins to cover up the face of the sun. An hour and a half later, at 2:30pm, we will reach maximum coverage. That maximum ends at...2:32pm. It will be another hour and a half until the moon fully exits the sun, but for some that maximum simply isn't enough.

Hence the anonymous question posted on my COSI whiteboard recently. The eclipse is covering the whole country, entering the US on the Oregon coast near the town of Newport and exiting the Atlantic side via Charleston, South Carolina. Any one spot along the path connecting those two cities will experience totality for around two minutes tops.

But what if we could drive - or better yet, fly - along that path, "catching" the totality in Oregon and riding it all the way to South Carolina? How fast would we have to go to really get the greatness of the Great American Eclipse?

Newport goes dark around 10:20am PDT, and Charleston doesn't follow suit until around 2:50pm EDT, so the most you're going to get for this eclipse is an hour and a half. Due to the moon's orbit the eclipse path doesn't take a direct line between the two cities, but we can take the great circle distance of 2,500 miles as good enough approximation, leading to a speed of 1,600 mph.

That's twice the speed of sound.