Public Invited to Mark Spring Equinox at the UMass Sunwheel on March 20

Source: UMass News & Media

The public is invited to celebrate the end of winter and the beginning of spring with a program at the UMass Sunwheel. UMass Astronomer Stephen Schneider will be at the sunwheel for an hourlong program at 6:45 a.m. and 6 p.m. on Thursday, March 20. The exact time of the vernal equinox is 5:01 a.m. Eastern Daylight time, as the sun moves from the southern to the northern half of the celestial sphere as seen from Earth. This marks the astronomical start of spring in the Northern Hemisphere and fall in the Southern Hemisphere. On the day of the equinox, the sun rises due east and sets due west and stays up for 12 hours.

Observers standing in the center of the sunwheel’s standing stones will see the sun rise and set over stones placed to mark equinoxes, very close to due east and due west. This astronomical change is also marked at the pyramid at Chichen Itza in Mexico and Stonehenge in England.

At the gatherings at the sunwheel Schneider will discuss the astronomical cause of the sun’s changing position. He will also explain the seasonal positions of Earth, the sun, and the moon, phases of the moon, and the building of the sunwheel.  An observer located at Earth’s equator will see the sun pass directly overhead at noon during the equinox, so they will cast no shadow. On any other day, either the Earth’s northern or southern hemisphere is towards the sun. At the poles, the sun skims the horizon as it circles in the sky over the course f the day, beginning six months of daylight at the North Pole and six months of darkness at the South Pole.

During the programs, Schneider will answer questions about astronomy. If it is clear, a solar telescope will be set up to safely observe the surface of the sun. Just before sunset, the sun can be seen between the tall standing stones that form a portal on the west side.

The UMass Amherst Sunwheel is located south of McGuirk Alumni Stadium, just off Rocky Hill Road (the continuation of Amity Street) one quarter mile west of University Drive. In the case of rain or blizzard condition, the events will be canceled. Visitors should be prepared for especially wet footing this year.

For more information, see here.