There’s an iconic moment, filmed in the shadow of the Very Large Array in New Mexico, that many people who visit this giant telescope try to duplicate. A young astronomer sits cross-legged on the bonnet of her car, the towering line of radio dishes vanishing into the distance behind her. With her laptop in front of her, she’s listening intently to a giant pair of headphones, held upside down so that the strap hangs below her chin. The shot is from the film Contact (1997), and the astronomer, Dr Eleanor Arroway (played by Jodie Foster), is listening, awestruck, to the first signal from an extraterrestrial intelligence. Having worked as a professional astronomer for more than a decade, I’ve met a number of colleagues for whom the film was an important part of their childhood. Many modern astronomers are driven by the ideals that Contact speaks to: the awe of discovery, and the search for company somewhere in this vast and empty Universe.
On 19 October 2017, the astronomer Robert Weryk spotted something rather extraordinary: a splinter of rock, just a few hundred metres across, tumbling through our inner solar system. Not much to write home about, you might think: there are more than 750,000 known asteroids and comets in our cosmic backyard, and countless millions more waiting to be discovered. But this object was very, very special. As his team would soon discover, this piece of flying cosmic debris could only have come from outside of our own solar system. The human race had found its first ever interstellar traveller.
The object was soon named ʻOumuamua: Hawaiian for ‘first distant messenger’ or ‘scout’ (and pronounced the way one might write an ode to a cow: ‘Oh, moo-er, moo-er’). More than three years later, the debate over ʻOumuamua’s true nature has spilled beyond the borders of academic astronomy and into the popular imagination. One reason why is obvious: a visitor from the stars – not in any metaphorical sense, but a real, tangible object right here, in our cosmic backyard – forces us to see ourselves as a small part of a wider Universe that exists far beyond our imaginative shores. There’s another reason, too: in our current space-faring culture, just as we’re launching missions to the planets and dreaming of visiting the stars, it’s inevitable that a tantalising question would arise – what if ʻOumuamua is more than a simple inanimate object? [Continue reading…]