Manhattenhenge 2013: Breathtaking solar alignment coming to a street near you

The sky starts to darken as you gaze upon some of civilization's most impressive stone monuments and see the Sun sink in perfect alignment with the structures to the west. Are you at Stonehenge? Standing near ancient Peruvian pyramids? Not necessarily. Depending on where you live and the time of year, you could just be looking down the street.

This just happens to be one of those times of the year, so if you're in Manhattan today or tomorrow (May 28th/29th), and if you can pause for a breather around sunset, you can look to the west along one of the borough's east-west oriented streets, and see the sun perfectly framed between the buildings.

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This 'phenomenon' is called Manhattanhenge, named after Stonehenge by astrophysicist Neil deGrasse Tyson, and it happens on four nights every year. This year, it's on May 28th and 29th, and it will happen again on July 12th and 13th.

"Good cross streets for viewing Manhattanhenge are 14th, 34th, 42nd and 57th," Dr. deGrasse Tyson said in an interview with TimeOut.com. "They are wide and are lined with interesting buildings to frame your photographs. You want to be as far east on your cross street as possible, while retaining a view across Manhattan to the New Jersey horizon."

It's not anything mystical, of course, and it isn't even entirely intentional (unlike Stonehenge). It's simply based on the change in the position of the sunset along the horizon throughout the year. For the same reason that the seasons change (the tilt of our planet's axis), the position of the sunset along the horizon slowly creeps to the north, day by day, until we reach the first day of summer, and then it slowly creeps to the south again, day by day until we reach the first day of winter.

This slow creep northward brings the sunset perfectly in alignment with the east-west streets of Manhattan roughly three weeks before and then again roughly three weeks after the summer solstice. The effect is completed by the contrast between the tall buildings of the city and being able to see all the way to the horizon past the Hudson River. Each night looks slightly different as well. Tonight will see a 'half-Sun', as the Sun perfectly lines up with the streets while it is halfway above the horizon. Tomorrow night will see a 'full-Sun', with the Sun hanging just above the horizon during alignment.

If you want to see this for yourself, but you're not in Manhattan, don't worry, this happens in other cities as well.

'Montrealhenge' should be happening along with Manhattanhenge, today and tomorrow and then again on July 12th and 13th.

'Torontohenge' won't be seen until around October 27th, and then again around February 12th.

Other notable ones include Ottawahenge around December 8th and again on January 3rd, and Calgaryhenge and Edmontonhenge (who's streets are laid out exactly east-west) on the equinoxes, around September 21st and March 21st.

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Nearly every city in the world can likely claim at least one street that lines up with the setting sun, but the best views of this 'henge-effect' are in cities that have closely-grouped tall buildings, streets laid out in a grid pattern, and relatively flat terrain towards the western horizon.

If you're interested in when you can see this in your city, try using this great online tool called 'SunCalc'. Just enter your location and play around with the dates to find out when the sunset will line up with the streets in your town.

(Photo courtesy: Reuters)

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