Stealing Daylight

Posted by Ethan on June 5, 2009
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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:

  1. 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.
  2. (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.

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  1. #1 Michel
    June 5, 2009

    You can even time travel!

    [quote]
    How to Time Travel for Under $100

    A humorous but real way anyone can time travel a small way into the future.

    Yes, you too can time travel for under $100 and you probably already have every thing you need to do it. In fact the main element is probably in your driveway.
    How To Do It

    Get in your car and go for a drive on a highway at 55mph for about 5 hours. Then turn around and refill your gas tank if needed. Next drive for another 5 hours back home for a total of 10 hours driving time.

    Now when you get home, you will have time traveled in to the future a wopping:
    100 Trillionths of a Second

    The total cost is probably less than $100 in gas.

    This actually works at any speed and for any drive time, but the calculations are for 10 hours of driving at 55 mph.

    So have fun time traveling.
    [/quote]

    While this intended as humor, the effect described is a real result of Einstein’s Theory of Relativity. It shows that the effect of Relativity in everyday life however small as it may be.

    (Source: http://www.scienceray.com/Physics/How-to-Time-Travel-for-Under-100.752987)

  2. #2 ScienceWoman
    June 5, 2009

    It’s considered higher latitude to go toward the poles no matter which hemisphere you are in.

  3. #3 Sili
    June 5, 2009

    Just go far enough, and you can stay put (well, the lack of roads will take care of that, I guess).

    You just have to move every six months.

  4. #4 Peter
    June 5, 2009

    Awww man! I just ran out of country (the UK is so small).

  5. #5 Matt
    June 5, 2009

    You can time travel for free!

    First, don’t move.

    Next, you’re done.

    You just traveled through time!

    Wait, wait a sec. I can’t stop, I’m still moving forward in time! aaaaah!

    I am now time traveling to the point in the future where I stop posting.

    See, nothing more from me!

  6. #6 PalMD
    June 5, 2009

    45 deg north is always a fun line to cross on our annual summer drive north. Halfway to the pole, w00t!

  7. #7 llewelly
    June 5, 2009

    alright. Explain how Superman flew around the Earth backward and did that time-travel thing. I never understood how that worked.

  8. #8 NewEnglandBob
    June 5, 2009

    llewelly:

    The superman time-travel thing works like this:

    I Think I Can…I Think I Can…I Think I Can…I Think I Can…I Think I Can…I Think I Can…I Think I Can…I Think I Can…I Think I Can…

  9. #9 anonymous
    June 5, 2009

    This reminds me of a video of some (ant)arctic researchers “running around the earth” – it took about 15s.

  10. #10 Michel
    June 6, 2009

    You know those globes that float with some magnetic help?
    (they look like this: http://images.google.com/images?q=floating%20globe&oe=utf-8&rls=org.mozilla:nl:official&client=firefox-a&um=1&ie=UTF-8&sa=N&hl=nl&tab=wi)

    What would be utter cool is a gig like that, but with a chair floating in it.
    On top of the pole.
    You sit still and see the world turn beneath you.

  11. #11 KoKo
    June 6, 2009

    There is an old sci-fi story in which a lunar explorer is trapped out on the surface of the Moon, and her suit won’t keep her warm enough during lunar night. So she *runs* entirely around the Moon, staying in sunlight the entire time. It seems plausible, actually. She wasn’t even at a very high latitude.

    Heh! She was literally being chased by a terminator! (snuk, snuk)

  12. #12 Chris B
    June 8, 2009

    Is West the best way to go? Since the “terminator” is at an angle to the longitude lines every day but 2, would you want to drive perpendicular to it? Would it matter the time of year? On the summer solstice, what angle would you want to drive NW to gain the most latitude advantage?

  13. #13 David Ratnasabapathy
    July 3, 2009

    Koko:

    A Walk in the Sun by Geoffrey A. Landis