Ashley Baxstrom: Today we celebrate the vernal equinox, herald of spring, which reportedly arrived at 1:14 am. Equinoxes occur twice a year, marking when the periods of night and day are just-about-equal. Here in the northern hemisphere, we appreciate that we’ll be receiving increasingly more warmth and light as the sun passes over the equator.

Cultures worldwide have long known about the equinoxes, using them for organizing calendars and celebrations. The Mayans, for instance, performed sacrifices at the pyramids of Chichen Itza, Mexico; the main pyramid, El Castillo, has 4 staircases built at an angle such that when the sun hits at the right moment of the vernal equinox, a shadow is cast resembling a snake winding up the stairs.

Today is also Nowruz, the Iranian (or Persian) New Year, also celebrated in the Zoroastrian calendar. In 2010, the UN General Assembly declared it an international holiday.

President Obama spoke today to mark the celebration, but used his remarks as an opportunity to call for the lifting of what he called Iran’s “electronic curtain,” saying his administration was working to provide software and services that would get Iranians greater access to the Internet and asking for direct dialogue with the people.