Petra in Jordan discovered that on the winter solstice,
the setting sun illuminates a podium in a building
known as the monastery. Exactly who or what was being
honoured is not known, but Juan Antonio Belmonte of
the Canaries Astrophysical Institute, who coordinated
the study, says the monuments of Petra ‘are marvellous
laboratories where landscape features and the events of
the sun, moon and other stars interact’. The alignment
of a tomb with the solstices and equinoxes represents
a deliberate attempt to turn the space ‘into a kind of
time-keeping device’, Belmonte says.
Where architecture acknowledges the movements
of the sun, it is most often to mark the solstices and
equinoxes. But other events have been honoured too.
The Great Temple at Abu Simbel in Egypt, completed
around 1265 BC, was oriented so that the sun’s light
would illuminate statues of gods in the temple’s
sanctuary – an immensely sacred spot deep in the
temple that would usually have been in darkness – on
22 October and 22 February. These dates are presumed
to have been significant to King Ramesses II, one of
the most famous pharaohs, to whom the temple is
dedicated: his birthday and coronation date, perhaps.
A tomb in Petra, which dates from the first century BC,
was later repurposed as a Christian church, and the
light that illuminated its corners on the summer and
winter solstices was instead said to mark Christmas
Eve and the birth of John the Baptist, which fall close
to the same dates.
We may no longer worship the sun, or stand in such
awe of those who harness its power in architecture, but
architects in our more recent history have continued to
employ the same kinds of tricks.
The church of Santa Maria degli Angeli e dei Martiri
in Rome features a 45m-long meridian line in its
marble floor, which together with a tiny aperture in
the south wall creates an indoor sundial. The line,
commissioned by Pope Clement XI and designed by
the astronomer Francesco Bianchini in 1702, reveals
a close relationship between those worshipping the
heavens and those observing them scientifically.
One might not expect the Catholic church to have been
so accommodating to astronomers in this period, ▼
The Urn tomb in Petra, Jordan. The monuments of Petra ‘are marvellous
laboratories where landscape features and the events of the sun, moon
and other stars interact’