It's the Manhattanal Equinox!

[MEBuckner]

Astronomy Picture of the Day: A Manhattan Sunset

Today, if it is clear, Manhattan will flood dramatically with sunlight just as the Sun sets precisely on the centerline of every street. Usually, the tall buildings that line the gridded streets of New York City’s tallest borough will hide the setting Sun. This effect makes Manhattan a type of modern Stonehenge, although only aligned to about 30 degrees east of north. Were Manhattan’s road grid perfectly aligned to east and west, today’s effect would occur on the Vernal and Autumnal Equinox, March 21 and September 21, the only two days that the Sun rises and sets due east and west. If today’s sunset is hidden by clouds do not despair – the same thing happens every May 28 and July 12. On none of these occasions, however, should you ever look directly at the Sun.

I just thought this was cool. All of y’all New York City Dopers paint yourselves blue and go dance naked in the streets or something.

[Billdo]

I’ve generally seen this called “solar grid day.” It’s always a cool effect, unless you’re walking crosstown and trying to see something, in which case it’s a pain.

[Podkayne]

Cool!

I’ve always enjoyed observing how my shadow stretches out parallel to the sidewalks at sunset and (one godawful year when I had to get up way too early for classes) at sunrise on the equinox. Kind of a geeky thing to get excited about, I guess, but it gives me a shiver to think what it would have been like for early humans to figure out that the Sun’s motion through the sky was regular and measurable and predictable.

[TellMeI_mNotCrazy]

And, because that’s the way life it is, it’s pretty damn gloomy here today.