When I tell people that I spend my days testing the possibility of life on Mars they usually reply in one of two ways. ‘No seriously, what do you do?’ is only slightly more common than the wittier ‘So you’re not holding out for much fieldwork, then?’ Astrobiology is a bright young discipline, aiming to answer some of the most fascinating questions within science and dinner-table conversation alike. Does life exist ‘out there’ among the pinpricks of light in the heavens, or are we alone in the cosmos? No current scientific field fires people’s fascination more than the quest for extraterrestrial life, and a large proportion of students have cited the reason for continuing science is their interest in astrobiology. For now many astrobiologists’ money is on Mars, our planetary neighbour, as it was once a lot like Earth.
The sleek animal glides effortlessly above the ground. The skin of her bullet-shaped body can smoothly change colour and pattern to match the surroundings, providing an almost perfect camouflage. The animal is on the hunt, and scans ahead with her acute vision. She spies her prey in the murky distance and banks gently towards it. As she approaches, the hunter slows and then hovers, the skirt-like fin along her flanks rippling gently to provide lift. The design on her back morphs into an all-together different pattern, this one a vivid, dynamic display. The whole animal appears to be pulsating as thick black and white stripes race across her surface, from the base of her body to the tip of her tentacles. The predator carefully edges nearer to its quarry and then suddenly jets forward, her tentacles exploding outwards to envelop the hapless prey in their clutches. It is quickly dragged in towards the beak, which crushes through the prey’s exoskeleton and gulps down its flesh. After this burst of ferocity the hunter switches back into perfect camouflage, and slips away unseen.
The USS Enterprise drops out of warp and slips into a parking orbit around an uncharted alien planet. The good Captain orders a scan for lifesigns, and within seconds he is being informed exactly what lifeforms are present, including the preindustrial tribes of humanoids on the southern continent. How feasible is this really? Well, unfortunately for Star Trek fans, identifying a species from orbit will perhaps forever remain in the realm of science fiction. For astrobiologists, however, revealing the presence of life on a remote planet is becoming possible even now, on 21st century Earth. Within a decade there will be telescopes capable of detecting the chemical fingerprints of life on planets nearly 50 light years away. And within out lifetimes there may even be telescopes able to image the oceans and continents of alien worlds.
The ambitious project of sequencing the DNA in the human genome released its first draft three years ago. At the time it was often portrayed as `reading the book of life’, but what is only recently being understood is how appropriate this metaphor really is. The jargon of molecular biology is scattered with terms borrowed from linguistics, such as transcribe, translate and code. The parallels between these two fields run much deeper than this though, and it has been discovered that both DNA and the proteins that it codes for have a grammatical structure like language. This has lead to the very productive swapping of ideas and techniques between biologists and linguists. For example, `authorship tests’ have been applied to unknown DNA sequences and `evolutionary trees’ have been constructed of old texts. But first, in what ways are DNA and proteins so profoundly similar to language? Continue reading
Recent genetic research has answered some long-running questions about the ancient origins of the humble cow. At the time when the first civilisations were being born great floods of cattle surged across the continents. The results of these prehistoric migrations may now help save modern European herds.