Time vs Distance

June 23, 2017 2:27 PM

How fast must I drive on the Interstate 80 in Nebraska to keep within the umbra of the eclipse mid Aug?
posted by hortense to Science & Nature (10 answers total)

Really, really fast

This was about a different eclipse, but still...
posted by It's Never Lurgi at 2:37 PM on June 23, 2017 [2 favorites]

The eclipse lasts about 1.5 hours from coast to coast, and it's about 2500 miles from Portland, OR to Charleston, SC. So you have to be going about 2500 miles / 1.5 hours = 1666 mph. The umbra is about 100 miles across, so you can't cover enough ground to lengthen the eclipse appreciably.
posted by ldenneau at 2:43 PM on June 23, 2017 [1 favorite]

That tallies roughly with my calculation. I used this map to pick out two places on I80 that have times associated with them - Lincoln and Lexington. The umbra moves from one to the other in about 6 minutes. That's 169 miles according to Google Maps, which gives a rough back-of-envelope speed of 1690 mph.

Concorde holds the record for the longest observation of a solar eclipse to date, which it set in 1973.
posted by pipeski at 2:44 PM on June 23, 2017 [1 favorite]

Best answer: Hmm, the animation at Nasa.gov shows the umbra entering Nebraska at 11:47 MDT and leaving roughly 20 minutes later. Google maps shows the length of I-80 (with slight diversion at the end to stay in the umbra) across the state as 450 miles, so roughly 1350 mph to stay in the shadow. Tried to avoid toll roads.
posted by sapere aude at 2:47 PM on June 23, 2017 [5 favorites]

Rough numbers:

From this page: https://eclipse2017.nasa.gov/sites/default/files/interactive_map/index.html

Total eclipse starts in Hershey, NE at ~17:53 UTC
Total eclipse ends in Lincoln, NE at ~18:03 UTC

~240 miles in 10 minutes, or ~1440 mph.

~twice the speed of sound.
posted by booooooze at 2:47 PM on June 23, 2017 [1 favorite]

Best answer: To put it another way: if you are standing still and on the centerline, totality will last about 140 seconds. If you are driving 100 mph, totality will last about 144 seconds.
posted by ldenneau at 3:00 PM on June 23, 2017 [13 favorites]

I don't care if this gets deleted I just have to tell you all how much I love this question and these answers.
posted by vrakatar at 5:03 PM on June 23, 2017 [22 favorites]

You've gotten several good answers, including some rough ways to calculate it. Here's another calculation. To a first order approximation, the earth is 24,000 miles in circumference and a day is 24 hours long, so the spot where the sun is directly overhead moves at 1,000 miles per hour. That's slower than all the answers so far, but still faster than you can drive on I-80.
posted by Bruce H. at 7:35 PM on June 23, 2017 [4 favorites]

Even ignoring the danger of driving that fast, driving while wearing eclipse glasses has gotten one person a Darwin Award. Yet one more practical problem with this...
posted by Anne Neville at 5:13 AM on June 24, 2017 [6 favorites]

NASA jets will get seven whole minutes of solar eclipse viewing!
posted by Eyebrows McGee at 9:18 PM on July 29, 2017