Sundials - World's Oldest Clocks

North American Sundial Society

Gardom Edge Monolith
[photo courtesy of Dan Brown, Nottingham Trent University]

A two meter standing stone at Gardom’s Edge may be an astronomically aligned monolith set up during the Neolithic period 2,500 – 1,500 BCE to recognize the summer solstice.   According to Dan Brown, Andy Alder and Elizabeth Bemand of Nottingham Trent University, “Such an astronomically aligned stone could be described as a seasonal sundial … However it is not intending to mark local time during a day or measure exact dates during a year.  Rather the seasonal shadow casting allows for the display of cosmological knowledge such as the ‘death’ and ‘rebirth’ of the Sun”…

The upward facing north slope of the stone remains in shadow until near the time of Summer solstice.  Today the stone points south at an upward tilt of 58.3° +/- 2.9°, seemingly aimed at the highest rise of the summer sun, computed for the Gardom Edge latitude of 53.26° as 60.7° in Neolithic times.

Read more: Gardom's Edge Monolith


One of the most iconic buildings in the world, the Pantheon in Rome is an enduring testament to the power and glory of ancient Rome.  At the same time, it has also always posed something of a mystery.  The only source of natural lighting is a thirty-foot diameter hole at the very top of the hemispherical dome, often referred to as the "oculus".

Working since 2009, scholars Guilio Magli and Robert Hannah discovered that at midday on the equinoxes, a shaft of circular light shines through the oculus and illuminates the Pantheon's entrance. 

Read more: Pantheon Sundial

[photo credit: Andrew Caswell and
Robert Cockburn of The Daily Telegraph ]

Ask a person what is the earliest evidence of humans building structures to mark significant celestial events, and one offer "Stonehenge".  But there may be a structure built thousands of years early according to some experts in Australia.

A site "down under", name Wurdi Youang, estimated to be older than 10,000 years, has a strange arrangement of stones with alignments toward solstices and equinox that has been scrutinized by several eminent Australian scientists.  They conclude that the placement and alignment of the stones is not an accident and there is a perfect alignment with the setting sun on the mid-summer day. Understandably, the exact location of the site is a well-guarded secret, but it is known to be west of Melbourne approximately 80 kilometers.

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