Humans measured time by the sunset and sunrise for millennia. Now, we're more apt to use our digital watches or even the changing energy state of atoms. But even in an age where we're glued to our smartphones, people are still very much swayed by the movement of the Sun around the Earth.

That's the lesson of a beautiful data project by Michelle Chandra, a graduate student at NYU's Interactive Telecommunications Program. Called "All Our Yesterdays," the project shows the location of photos uploaded to Instagram with the hashtags #sunrise and #sunset in the past 24 hours. It is updated in real time, giving a mesmerizing depiction of the never-ending loop of the rising and setting sun.

Here are the #sunrise photos from the last 24 hours, mapped by location:

And here are the #sunset photos:

It's once you put them together in real time that things get beautiful. This is what the map looks like for the past 24 hours:

The bigger the dot, the closer the user is to an actual sunset or sunrise time when uploading the photo. If you look closely, you can see that the red dots, indicating the sunset, tend to cluster together more tightly than the yellow dots that indicate sunrise. Chandra says that Instagram users tend to upload photos of the sunset within four hours of the event, but many seem to wait until the end of the day to post photos about the sunrise.

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