Data Driven Digest for December 22: The Passage of Time in Sun, Stone, and Stars

Data visualization has been with us since the first cave-dweller documented the lunar month as a loop of symbols carved onto a piece of bone that hunters could carry with them to track the passage of the seasons.

Obviously, technology has moved on in the past 34,000 years – have we told you lately about our iHub dashboards and embedded analytics? – but since the winter solstice (for the Northern Hemisphere) occurs Tuesday, Dec. 22, we thought this would be a good time to review some of the earliest efforts to create live, continuously updated reports of astronomical data, out of stone structures and the landscapes around them.

Diagram of how the winter solstice light enters Newgrange, from After Stout, G. & Stout, M. 2008, Newgrange, Cork University Press, Cork.


The fact that many of these calendars still exist after thousands of years, and still work, shows that our prehistoric ancestors must have considered visually recording the time of the year mission-critical, to predict hunting and harvest times, plus other seasonal events such as spring thaws, droughts, and monsoons.  (Whether accurately predicting and planning for those events was part of their yearly job performance review, we leave to the archaeologists…)

So step outside and, if the weather permits, take a look at the sunrise or sunset and notice exactly where it hits the horizon, something our ancestors have done for thousands of generations.  Then come back into your nice warm room and check out these links.  Enjoy, and happy holidays!

Sun Daggers

The winter solstice is the time of year when the days are shortest and nights are longest.  As such, it was an anxious time for primitive people, who wondered when their world would stop getting darker and colder.  That’s why early astronomer-priests (the Chief Data Officers of their time) designed calendars that made clear exactly when the day reached its minimum and the sun was at the lowest point on the horizon – and would then start returning.

One of the most impressive solar calendars is at Maeshowe, a 5,000-year-old “chambered cairn” in the Orkney Islands, north of Scotland.  It’s a long passage built of stone slabs dug into an artificial mound.  The passage is oriented so that for a few days around the winter solstice every year, the rays of the setting sun reach all the way down to light up the door at the end.  Two markers pinpoint the sun’s path on the exact date of the solstice: a monolith about half a mile away, called the Barnhouse Stone, and another standing stone at the entrance to Maeshowe (now missing, though its socket remains).

Maeshowe, showing the Barnhouse Stone in front. Photo credit: Odyssey Adventures in Archaeology, Ontario, Canada




A laser-scan image through 3D point cloud data shows a cross-section of the Maeshowe chambered tomb. © Centre for Digital Documentation and Visualisation LLP and


Even more impressive is Newgrange, a 5,000-year-old monument near Dublin, Ireland.  Newgrange was built as a 76-meter-wide circular mound of stones and earth covering an underground passage, possibly used as a tomb.

A hollow box above the passage lets in the rising sun’s light for about 20 minutes at dawn around the winter solstice.  The beam starts on the passage’s floor, then gradually reaches down the whole 19-meter length of the passage, flooding it with light.  It’s an impressive spectacle, one that attracts thousands of people to the Newgrange site for the six days each December that the sunbeam is visible.

The sun’s rays reach the inmost chamber at Newgrange only at sunrise around the winter solstice. Photo credit: RTE News, Ireland, 2013


Nor were early Europeans the only ones taking note of the sun’s travels across the landscape.  At Fajada Butte, New Mexico, three stone slabs were positioned so that “dagger”-shaped beams of sunlight passing between the parallel slabs travel across carved spirals on the cliff face beneath at the summer and winter solstices and spring and fall equinoxes.

Fajada Butte, NM, at twilight. Photo credit: Wikimedia user Joeykujawski – Own work. Licensed under CC BY-SA 3.0 via Commons


Fajada Butte is part of the Chaco Canyon complex, inhabited between the 10th and 13th centuries by the Anasazi or Ancestral Puebloans.  They built impressively engineered cliff dwellings, some as high and densely populated as big-city apartment buildings, laid out 10-meter-wide roads that spanned modern-day New Mexico, and harvested snowmelt and rainwater for irrigation through a sophisticated system of channels and dams.  The Anasazi religion was apparently based on bringing the order seen in the heavens down to earth, so many of their sites were oriented north-south or towards complex alignments of sun, moon, and stars – which may explain why Fajada Butte was just one of many solar observatories they built.

Pueblo Bonito, one of the largest buildings at the Chaco Culture site. Photo credit: John Wiley, Wikimedia User:Jw4nvc – Santa Barbara, California – Own work. Licensed under CC BY 3.0 via Commons


Researchers at the Exploratorium in San Francisco have designed an interactive simulator of how the Sun Daggers worked:

Click through to reach the interactive Sun Dagger demo
Copyright the Exploratorium, San Francisco, CA


Looping Through Time

From the passage of time documented in stone and earth thousands of years ago to the wanderings of a Time Lord:  Just in time for the annual “Dr. Who” Christmas special (and the beloved sci-fi show’s 50th anniversary), our friends at the BBC have created a clever interactive map of the travels through time of all 11 incarnations of Dr. Who.

This looping diagram ingeniously displays all the journeys by actor, episode, and whether the trip was into or out of the past and future, as well as the actual year.  It’s not a linear chronology, but the course of a Time Lord’s adventures, like true love, never did run smooth.

Light on Embedded Analytics

Meanwhile, we’re hoping to shed some light on a topic dear to our heart – analytics.  On Jan. 12, 2016, we’re hosting a Webinar featuring TDWI Research Director Fern Halper, who will talk about Operationalizing and Embedding Analytics for Action.

Halper points out that analytics need to be embedded into your systems so they can provide answers right where and when they’re needed.  Uses include support for logistics, asset management, customer call centers, and recommendation engines—to name just a few.  Dial in – we promise you’ll learn something!

We share our favorite data-driven observations and visualizations every week here.  What topics would you like to read about?  Please leave suggestions and questions in the comment area below.

Recent Data Driven Digests:

December 18: The Data Awakens

December 11: Holiday Lights

December 4: Winners of the Kantar Information Is Beautiful Awards

Stannie Holt

Stannie Holt is a Marketing Content Writer at OpenText. She has over 20 years' experience as a journalist, market research analyst, and content marketing expert in the fields of enterprise business software, machine learning, e-discovery, and analytics.

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