Words by Lydia Paleschi
The first astronomers looked up to the sky thousands of years ago. What they saw wouldn’t have been all that different to what we see today – a depthless canvas of ebony interspersed with scintillating stars and peculiar planetary line ups. As they gazed beyond the stratosphere and recorded their findings they would begin to uncover secrets from within it. Soon, these observations would inform religion, philosophy, agriculture, politics and even matchmaking, as well as leading to the creation of calendars and our understanding of time.
The earliest evidence of astronomy comes from an era before written records were kept. In it, prehistoric carvings from around Europe and Africa pay homage to the Sun and the Moon, their rays clearly depicted alongside small clusters of stars which had been etched into the rock. In China, pottery estimated to be 5,000 years old shows astronomical events such as epic star explosions and streaming comet showers, their remnants on display today in the Beijing Ancient Observatory. In northeastern Africa, the oldest known stone circle – Nabta Playa – stands almost 7,000 years old. Found around 700 miles south of the Great Pyramid of Giza in Egypt, it is thought to track both the summer solstice and the arrival of the monsoon season.
Prehistoric cave art depicts celestial bodies
A Mandate from the Sky
Around 3,500 BC, the first written records began to appear. In Mesopotamia, ancient Babylonian temple scribes would engrave the night’s happenings on clay tablets, keeping them for information and trying to interpret them as messages from the Gods to be passed on to the king. Certain celestial signs were thought to signify increased chances of drought, famine, war or disease (amongst other things) and would serve as a pre-warning of the hardship that lay ahead. By the 7th century BC, astronomical diaries began to emerge. Created from generations of stargazers, these writings made it possible to predict the patterns of the Moon and the planets.
Simultaneously, Chinese Emperors were attempting interpretations of their own. Much like in Mesopotamia, the Chinese would base decisions on celestial readings. However, theirs were used more extensively, to inform both daily life and major political strategies. Stars were bestowed with astrological meanings and the appearance of unusual events such as eclipses, comets and star explosions were documented. China’s astronomical history is unique in that it was recorded uninterrupted for over 4,000 years – longer than any other known civilisation.
Su Song's star maps are amongst the oldest in printed form
The Ancient Greeks
By the 4th century BC, the Ancient Greeks were pioneering astronomical discovery. Building upon the knowledge of the Babylonians, they applied mathematics and geometry to their understanding of cosmic questions. By doing so, they were able to work out that the Earth is round and to make the first (almost) accurate estimate of its circumference. Amongst the most famous of Greek astronomers is Ptolemy, remembered for his star catalogue and geocentric (Earth-centred) model of the Universe. Greek and Roman mythology also inspired the names of some of the most famous constellations, including the zodiacs, whose positions are still referenced today in astrological charts and horoscopes.
Ptolemy developed a geo-centric astronomical model
India, the Islamic World and Medieval Europe
After Ptolemy, Ancient Greece’s astronomical works travelled to India and into the Islamic world. From 800 AD, Arabic astronomers would spend centuries improving on Ptolemy’s models, though not deviating from its central tenets. At this point, the field of astronomical discovery was dwindling in Europe. However, by the 15th century translations of Arabic and ancient Greek texts meant that Europeans could once again build upon past findings. In 1543 Copernicus announced the motion of the Earth in his Six Books Concerning the Revolutions of Heavenly Orbs, in the 1600s Galileo published a more in depth knowledge of the moon and that other planets also had moons with their own orbits. In 1609, Kepler’s first law announced that all planets move around the Sun in elliptical orbits, with the Sun as one focus of the ellipse. In 1687, Newton’s law of gravitation went some way in explaining how and why these orbits are possible.
A diagram of the solar system from the Renaissance Period
Since Newton, the work of Einstein and many others has deepened our understanding of gravity, light and a number of other astronomical phenomena. Today, technology allows us to learn much more about what lies beyond our atmosphere. We are able to measure distances in space much more accurately and understand that stars are in fact blazing balls of helium and hydrogen. Sophisticated apps such as SkyView allow us to point our phones in any direction to identify celestial bodies.
We now know that the Earth forms part of a solar system which orbits the Sun whilst rotating and that this solar system forms part of the Milky Way, one of innumerable galaxies. However, despite an age-old fascination with the astronomy and numerous impressive discoveries, the limitless expanse of the Universe means that we still know very little about what it is we are a part of. It’s still possible to gaze up into the abyss and not know what it is we are looking at, what it means or where it came from. Despite lifetimes of work by astronomers from around the globe, the night sky is still shrouded in an aura of mystery and enchantment.