Questions people ask about the ancient Sun

A pattern of light on Fajada Butte in Chaco Canyon. Three leaning sandstone slabs let blades of sunlight fall on a carved spiral, marking the solstices and equinoxes.

Its great houses were built in stages between about 850 and 1150 CE, dated precisely from tree rings in roof beams.

Several were. Pueblo Bonito has walls close to north–south and east–west. Other buildings may follow lunar directions. Not every proposed alignment is accepted.

Chaco Culture National Historical Park is open year-round and sometimes runs solstice programmes. Check with the park before you go; Fajada Butte itself is closed.

For several days around the spring and autumn equinoxes, in the late afternoon. Clear skies matter more than the exact date.

Several cycles ran together: the 365-day Haab’, the 260-day Tzolk’in and their 52-year Calendar Round. The Long Count measured longer spans.

The two days a year when the noon Sun is straight overhead in the tropics. In the northern Yucatán this happens in late May and mid-July.

No. 2012 marked the end of a large Long Count cycle, like a counter rolling over. Maya inscriptions refer to dates far beyond it.

Earth’s axis is tilted about 23.44°, so the Sun’s declination changes through the year and its rising point swings north and south.

The swing grows with latitude. At 36° N it is about 59°; at 21° N about 50°.

Almost, but not quite. Refraction and the size of the Sun’s disc make daylight a few minutes longer than 12 hours on the equinox.

It explains the Sun as a magnetic star with an 11-year cycle, solar wind and storms that shape space weather around Earth.

No. That educational project ended long ago. This is an independent editorial project with new text, viewers and guides.

Yes. Download or print them for personal and non-commercial teaching use. No sign-up is needed.

Sun positions are calculated for each site’s latitude on a flat horizon without refraction. Expect differences of a degree or so against a real skyline.

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