News that our colleagues at the National Maritime Museum are busy raising funds to acquire two oil paintings by the 18th century artist George Stubbs has set me thinking about connections with the Royal Observatory’s current exhibition Alien Revolution: the changing perception of extraterrestrial life.

The paintings in question, Kongouro from New Holland and Portrait of a Large Dog, are the earliest representations in western art of what have now become iconic Australian animals: the kangaroo and the dingo. They were commissioned from Stubbs by the great naturalist Sir Joseph Banks who had accompanied Captain James Cook on his first Pacific voyage aboard HMS Endeavour in 1768-71. The primary goal of this expedition was astronomical – to observe the 1769 transit of Venus from the island of Tahiti – but, famously, Cook’s subsequent instructions were to sail on to explore the coastline of ‘New Holland’, the vast unknown continent that we now call Australia.

The Kongouro from New Holland (Kangaroo), George Stubbs; oil on panel, signed and dated 1772. Private collection. Courtesy of Nevill Keating Pictures Ltd.

This mission resulted in an explosion of scientific discoveries, and Banks’ reports of strange new plants and animals captivated the public imagination on his return. Stubbs’ paintings therefore represent an important cultural and scientific moment: an 18th century European encounter with alien life from a distant and unfamiliar environment. They also record a turning point for the people and animals of Australia, when contact with Europe was about to alter their world forever.

In a similar vein, the Observatory’s exhibition Alien Revolution explores how science and imagination have shaped the way we think about life elsewhere in the Universe, and how changing ideas about extraterrestrial life have in turn affected our understanding of life here on Earth.

The exhibition’s story starts in the 16th century with the Polish astronomer Nicolaus Copernicus and his heliocentric model of the cosmos, which displaced humanity from its privileged position at the centre of everything - in the process sowing the seeds for ideas about life on other planets. By the late 18th century the concept of extraterrestrials was widely debated, with Stubbs’ contemporary, the astronomer Sir William Herschel, even speculating about the possibility of life on the Sun. The story continues via Percival Lowell’s Martian ‘canals’ and the sci-fi-obsessed 20th century to the brand new science of astrobiology and our modern fascination with SETI, the Search For Extraterrestrial Intelligence.

If Stubbs’ Kongouro seems anatomically awkward to modern eyes this is hardly a reflection on the skill of the artist - never having seen the living animal all he had to go on were written descriptions, some sketches and a rather haphazardly inflated kangaroo skin. Attempts to depict extraterrestrial life are similarly hampered by the inconvenient fact that (UFO reports not withstanding) no one has ever actually seen an alien.

Despite this rather obvious handicap, scientists and artists down the centuries have spared no effort in turning scientific ideas and pure speculation into visualisations of what alien lifeforms might look like – with varying degrees of plausibility. Alien Revolution includes several of these exercises, and my own favourites are the almost ‘life-sized' reproductions of imaginary extraterrestrials painted by the science fiction and fantasy artist Wayne D. Barlowe.

Alien invasion: Wayne D. Barlowe’s visualisations of fictional aliens on display at the Royal Observatory Greenwich as part of the Alien Revolution exhibition. Left: 'Cygnostik' from 'A Little Knowledge' by Michael Bishop. Right: 'Vegan' from 'Have Spacesuit Will Travel' by Robert A. Heinlein.

Like Stubbs, Barlowe was working from written descriptions of his subjects, this time from classic science fiction novels by writers such as Arthur C. Clarke, Robert A. Heinlein and Jack Vance. In many cases the authors have taken great pains to base their fictional aliens on plausible science, so Barlowe’s renderings take account of physical and biological constraints as well as his own imagination.

Wayne D. Barlowe’s visualisation of a 'Sulidor' from Robert Silverberg’s novel ‘Downward to the Earth’ contemplates tea at the Royal Observatory's café.

It may be fun - if rather frivolous - to think of Stubbs’ Kongouro from New Holland as an early example of sci-fi art, but the painting also illustrates a more serious point about the way we see ourselves.

When Europeans first ‘discovered’ Australia human beings had already been living there for 50,000 years - a lot longer than the presence of Homo Sapiens in Europe itself.

During this vast span of time the indigenous peoples of Australia had developed a sophisticated cultural toolkit for life amid the harsh and fragile environments of their island continent, without the need for advanced technology. But, intentionally or otherwise, contact with technologically endowed Europeans had unfortunate consequences for these ancient cultures.

Perhaps we should bear this in mind in the 21st century as we eagerly search the stars for signs of intelligent life. The Universe has existed for 13.8 billion years and the chances are that any other civilisations out there have already been around for a lot longer than we have. Some scientists have suggested that the culture shock of encountering aliens with powers and technology thousands or even millions of years more advanced than our own might be overwhelming, even if the aliens themselves had only benign and friendly intentions towards us.

Alien Revolution includes a quote from the physicist and cosmologist Stephen Hawking, who warns "If aliens visit us, the outcome would be much as when Columbus landed in America, which didn't turn out well for the Native Americans". He might equally have used the example of Captain Cook and the people and animals of New Holland.

As we gaze at Stubbs’ wistful and slightly awkward Kongouro perhaps we should ask ourselves a correspondingly awkward question: is this how advanced extraterrestrials might gaze at us?

Alien Revolution runs until 8 September at the Royal Observatory Greenwich and entry is free. Kongouro from New Holland and Portrait of a Large Dog are on display in the National Maritime Museum's Sammy Ofer Wing until 5 November. You can donate to the appeal to acquire the paintings here