Ever wonder how much daylight you can gain or lose just by getting in your car and driving either West or East?
Here’s how to figure it out. The Earth’s circumference is about 25,000 miles (40,000 km) at the equator. So if you start out at sunrise and drive 1,000 miles (1,600 km) Westward during the daylight hours, you’ll get almost an extra hour of daylight. On the other hand, if you go East, you’ll lose that much. 1,000 miles is pretty much the maximum you can go in about 12 hours, and that’s going pretty fast (about 80 mph, or 130 kph).
But there’s a trick to stealing extra daylight.
Get away from the equator. The higher (it’s my northern hemisphere bias; sorry, Aussies!) your latitude is right now, the better you’re going to do. There are two reasons:
- It’s summer in the northern hemisphere, so you start with more daylight hours. This gives you more time to travel, and the farther you go, the more daylight you can steal.
- (And this is the big reason.) The distance to go around the Earth is much shorter.
Seriously. In math-ese, the latitudinal circumference of the Earth is the equatorial circumference times the cosine of your latitude. In a more reasonable format, here’s a table for you:
|Latitude (°)||Circumference (mi)||Circumference (km)||Extra light per 1,000 mi|
|0°||25,000 mi||40,000 km||58 minutes|
|10°||24,600 mi||39,400 km||59 minutes|
|20°||23,500 mi||37,600 km||1 hour 1 minute|
|30°||21,700 mi||34,600 km||1 hour 6 minutes|
|40°||19,200 mi||30,600 km||1 hour 15 minutes|
|50°||16,100 mi||25,700 km||1 hour 29 minutes|
|60°||12,500 mi||20,000 km||1 hour 55 minutes|
|70°||8,600 mi||13,700 km||2 hours 47 minutes|
|80°||4,300 mi||6,900 km||5 hours 34 minutes|
I’m currently up at a latitude just north of 45° on a road trip, marveling at the fact that going East vs. going West gives me a difference of three hours of daylight. Imagine being up inside the Arctic Circle; it’s actually possible to outrun the Sunset!
And now you, too, can lengthen or shorten your days — at will — just by getting in your car.