Wednesday, September 23, 2009
The Sun Wheel at UMass Amherst
I've always enjoyed looking at the standing stones behind the UMass football stadium, but I never knew who put them there or what their purpose was.
Tuesday I met astonomer Judith Young, the driving force behind the sun wheel, as it is called, who explained why the stones were placed where they were and how the early peoples who built stone wheels used them as calendars.
A group of about 30 people learned all about solstices and equinoxes, sunrises and moonrises, even the 26,000 year cycle of the North Star. Seems even the pole star moves, but not enough so you'd notice it in a fleeting human lifetime.
Solstices are the longest and the shortest days of the year and equinoxes are when day and night are equal.
I've always heard that after the winter solstice, the days get longer by about one minute per day on average, and I've always wondered if they get longer by one minute every day or do they grow longer faster at some times and slower at others.
Professor Young explained that the days grow longer very slowly around the solstices in December and July and much faster around the equinoxes, which you would think would come exactly halfway between solstices, but you'd be wrong because the earth's orbit around the sun in not perfectly round, but slightly elliptical, and on top of that the earth's axis is tilted.
But the answer to my question is that the days get longer faster in the middle of the winter.
You can find out more about the Sun Circle at Young's website.
¶ 2:24 PM Tuesday I met astonomer Judith Young, the driving force behind the sun wheel, as it is called, who explained why the stones were placed where they were and how the early peoples who built stone wheels used them as calendars.
A group of about 30 people learned all about solstices and equinoxes, sunrises and moonrises, even the 26,000 year cycle of the North Star. Seems even the pole star moves, but not enough so you'd notice it in a fleeting human lifetime.
Solstices are the longest and the shortest days of the year and equinoxes are when day and night are equal.
I've always heard that after the winter solstice, the days get longer by about one minute per day on average, and I've always wondered if they get longer by one minute every day or do they grow longer faster at some times and slower at others.
Professor Young explained that the days grow longer very slowly around the solstices in December and July and much faster around the equinoxes, which you would think would come exactly halfway between solstices, but you'd be wrong because the earth's orbit around the sun in not perfectly round, but slightly elliptical, and on top of that the earth's axis is tilted.
But the answer to my question is that the days get longer faster in the middle of the winter.
You can find out more about the Sun Circle at Young's website.
