You’re reading Significant Digits, a daily digest of the numbers tucked inside the news.

Today, a large portion of the United States will experience a solar eclipse! Here’s an all-eclipse version of Significant Digits. I’ll be co-anchoring ABC News’ digital coverage of the eclipse, watch it here.

1 hour, 33 minutes, 16.8 seconds

Duration of the eclipse on U.S. soil today from Oregon to South Carolina. A solid 70-mile-wide swath of the country coast-to-coast will get to experience a total solar eclipse for anywhere from a few seconds to over two minutes. It may be responsible for the largest mass migration to see a natural event in human history. [The Atlantic]

45 million pairs

Number of eclipse glasses — the approved way to view a solar eclipse without permanent retina damage — sold by American Paper Optics (one of the few authorized sellers of certified glasses) over the past two years. Do what you can to get your hands on a pair; it’s unsafe to attempt to stare directly at the sun. [ABC News]

1,651 miles per hour

Average speed of the eclipse as it sprints across the country. While the big event is going on, a considerable amount of research will be happening, as briefly blocking out the sun is a handy way of studying everything from earth’s ionosphere to how animals react to eclipse-induced midday temperature and light swings. [FiveThirtyEight]

75 million

Approximate number of people who live within a 200-mile drive of the path of totality across the country. About 12 million people live directly in the path of totality; experts estimate they could be joined by about 7.4 million people traveling to watch the eclipse. That could make for some serious traffic and clogged cellular networks. [FiveThirtyEight, Curbed]

29

Number of interstate highway routes that the total solar eclipse crosses. State and local officials are working to ensure that first responders and highway crews can react in a timely matter with or without access to cellular networks. [Time]

3.2 percent

Percent of energy generated in North Carolina from solar power in 2016. The nation is about to experience a slight dip in solar power generation, and the planning to react to the eclipse has underscored a number of issues regarding the state of infrastructure in the U.S. Regardless of how this time goes, by 2024 — the next time the U.S. is due for a solar eclipse — we’ll need to be ready. [FiveThirtyEight]

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