Space Forum / Astronomy / September 2006

http://www.nytimes.com/2006/09/29/travel/escapes/29chimney.html

Where the Moon Stood Still, and the Ancients Watched

By MIRIAM HORN
Published: September 29, 2006

THE great Chaco civilization, trading partner of the Maya,
established a far-reaching sphere of influence in the North
American desert a millennium ago. Among the most
remote and mysterious of their outposts was Chimney
Rock, in what is now the very southwest corner of
Colorado, 90 miles from Chaco Canyon in New Mexico,
the center of the culture.

Why did the Chaco people - the Anasazi, or "ancestral
Puebloans," as their descendants prefer - build an
enormous ceremonial Great House at Chimney Rock, so
far from home, 1,000 feet above the nearest water supply
and at the base of immense sandstone spires?

It was not until two decades ago that archaeologists arrived
at an explanation that most now accept: the Chaco people
built the Great House as a lunar observatory precisely
aligned to a celestial event that occurs just once in a
generation.

That rare event, a "major lunar standstill," is happening now,
and continues through 2007. To witness this extraordinary
moonrise, some two dozen visitors, including me, arrived
to climb the Chimney Rock mesa in the middle of an
August night.

Every 18.6 years, the moon does something strange: it
radically expands the voyage it makes each month across
the sky and, at the northern and southernmost edges of
that journey, appears to rise in the same spot for two or
three nights in a row.

What archaeologists discovered at the last occurrence of
this event - in the mid-1980's - was that if you stood
atop the Chacoan Great House at Chimney Rock (or as
we did, on the modern fire watchtower that stands in front
of the Great House and replicates its alignment), you saw
the northernmost moonrise directly between the sandstone
spires. Move anywhere else on the mesa, and the shift in
perspective slipped the moon from its frame.

The current recurrence of the cycle began in December
2004. With permission from the local Pueblo tribes, for
whom Chimney Rock remains sacred, the United States
Forest Service began in 2005 to allow visitors up the
mesa seven nights a year (once a month, from July through
January) to watch the moonrise. Similar moonrises occur
at Stonehenge and at Callanish in Scotland, the two other
sites in the world where archaeo-astronomers have found
substantial evidence that preliterate peoples used
immense stone structures to mark the place in the sky
where the moon stands still.

On the night I attended, it was nearly 1 a.m. when we began
the quarter-mile climb. First, there had been midnight
muffins and T-shirt sales at the tiny visitor center, chirpy
greetings from local volunteers and the reading of a list
of prohibitions, each born (our guide later told me) of
earlier difficulties with "new age" celebrants, who are
drawn to the event by the mystical associations with
megaliths and aboriginal peoples, and by the moon's
traditional importance in animism, astrology and the
"lunacy" of poets and visionaries.

"The Puebloan community believes that the spirits of their
ancestors still inhabit this place, and ask that there be no
religious ceremonies by non-native visitors," a volunteer
read. "Please refrain from chanting, singing, burning
incense, audible prayers, whooping, hollering, rattles or
drums." Because noise would disturb the falcons nesting
on the rocks, she added, we were to make our final
ascent in silence.

The sky was nearly cloudless when we set out. It was
packed with celestial bodies, the smears of the Milky
Way and long scribbles of falling stars, the last remnants
of the Perseus meteor shower. A few conversations
floated on the air, hinting at the reasons people had
come. Two men swapped tales of their travels to see
the northern lights and the Southern Cross; a gray-haired
woman whispered intensely to her companion about her
healings with a Mayan shaman. Nearby, a young couple
kept silent, nuzzling beneath the pines.

As we approached the spires, the ridge narrowed to a
knife edge and the pinyon-juniper forest dropped sharply
away. Cresting the mesa (itself 7,600 feet high), we
switched off our flashlights to immerse ourselves in the
deep black of the mountain night.

Our Forest Service guide, Ron Sutcliffe, began to explain
that "the moon is a more complex creature than any planet
or star in the sky," because of its eccentric orbit and gravi-
tational interactions with the Earth. An engineer and
surveyor by profession, Mr. Sutcliffe is also a "naked-eye
astronomer" who has been watching the moon for more
than a decade. He moved here, he said, because this
mesa is one of the world's great natural observatories.

Though we were in the Rocky Mountains, with the
Weminuche Wilderness to the north and South San Juan
Wilderness to the east, Mr. Sutcliffe showed us how this
plateau forms a natural planetarium, with a uniform
horizon broken only by the cut of the river now called the
Piedra (it was named El Rio de la Piedra Parada, the
river of the standing rock, by Spanish missionaries in
1776) and by the spires, which precisely demarcate the
paths of the stars, sun and moon. One by one he showed
us the constellations, working his way around the zodiac.
When Taurus rises, he told us, we would know the moon
is near.

The lunar standstills occur during a different lunar phase
each month, and at a different time of day. For the first
half of each year, they are invisible because they happen
during daylight hours (which is why there are no Forest
Service events from February to June). The first visible
moonrise between the spires occurs in July, when the
moon is a slender crescent rising before dawn. By
September it is a half-moon rising at midnight; in
October and November it is a fattening gibbous; and by
December it is a full moon rising at sunset.

In 2003, Mr. Sutcliffe figured out when each of the 114
"standstill" moonrises would occur between 2004 and
2007. Every May, the Chimney Rock Interpretive
Association sells 24 tickets for seven of the moonrises
that will be visible in the coming year (the other nights
are generally reserved for Native Americans from the
region); this year, all the tickets were sold in three days.

As he talked, Mr. Sutcliffe kept watch on the sky. As the
bright star Aldebaran in the Taurus constellation edged
above the horizon, he announced the moon's imminent
arrival: "Taurus, our herald, has risen." He led us to the
north edge of the mesa to wait in silence as a glow
slowly washed the sky. After many long minutes, a tip of
the silvery crescent appeared in the cleft between the
spires and slowly inched into view, like a moth emerging
from a dark chrysalis.

With three-quarters of the crescent revealed, the moon
floated briefly between the spires. Confirming what I'd
always thought to be folklore, coyotes began to yip and
howl all around us from the desert below. They fell silent
only when the moon disappeared behind the spire, an
ember burning out, leaving an opalescent moonglow
behind.

Strangely moving as it was to stand silently with strangers
in the desert at night, all gazing fixedly on the sky, it was
stranger still to think that a lunar pattern that recurs so
rarely could have been perceived by a preliterate com-
munity whose average individual life span would have
barely embraced two cycles. Yet archaeologists have
amassed considerable evidence that the great struc-
tures at Chimney Rock were in fact built for the express
purpose of gathering as many people as possible to
witness the standstill in one of the few places on earth
where geology provides the necessary frame.

THE most persuasive evidence comes from dendro-
chronology, tree ring dating, which places the two major
episodes of construction at Chimney Rock 18 years
apart and coincident with the northern lunar standstills of
1076 and 1094. The architecture provides additional
clues: While the masonry of the Great House is indisput-
ably Chacoan, the siting of the house is wildly strange.

The house is built of six million stones, 25,000 tons of
earth and clay and 5,000 logs, and its construction
required laborers to haul wood, food and water from the
valley floor, two miles away and 1,000 feet down. And
rather than center the house on the mesa, where one
would expect, they shoved it right to its northern edge,
creating the broadest possible platform from which to
see the moon rising between the rocks.

Evidence of ancient knowledge of the lunar standstill
has also been found elsewhere in the region, on
Fajada Butte in Chaco Canyon and at the Cliff Palace
at Mesa Verde, built in the century after Chaco and
Chimney Rock were abandoned.

So what was it for? Most archaeologists argue that the
massive, decades-long effort to build the Great Houses,
and the marking over several generations of the rhythms
of the moon, served to unify Chacoan society across
broad reaches of desert and time. Others emphasize
political authority: the ability to predict the movements
of the moon would have bolstered the leadership's legiti-
macy, particularly because the Chacoan florescence
coincided with an extraordinary degree of celestial activity.

Between 1020 and 1100, 70 lunar eclipses could be seen
from Chaco Canyon. The supernova of 1054, which
created the Crab Nebula, was visible even in daylight for
23 days. Halley's Comet passed in 1066. Total solar
eclipses were visible in Chaco and Chimney Rock in
1076 and 1097.

Mr. Sutcliffe is impatient with the archaeological habit of
imputing utilitarian purposes to the ancients' infatuation
with the moon; he believes people often pursue know-
ledge for its own sake. That faith was evident when we
climbed down from the mesa and discovered he had his
PowerPoint ready. It was almost 3 a.m., and growing
colder, as he began to explain "the obliquity of the ecliptic"
while the attention of his 24 observers faded, like
constellations slipping from the sky.
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