Scitech  Earthly exo-planets

The implications of Gliese 581 g

Hollywood blockbusters and science fiction literature muse about what is beyond the boundaries of our earth, and wonder if there might be life on other planets. Empirical discoveries, like that of Gliese 581 g, a distant earth-like planet, can offer insights that go beyond mere speculation about the uniqueness of life on earth. 
The discovery is credited to a team of planet hunters led by American astronomers Steven Vogt and Paul Butler. The finding comes after almost a year of uncovering several similar earth-like planets orbiting Gliese 581, a star in the Libra constellation. What is unique then, about “g”? “[Gliese 581 g] is within the ‘habitable zone,’ which can be defined as the physical space in a star’s orbit in which the conditions for life, namely temperature, are met,” explained Hojatollah Vali, professor of Astrobiology at McGill. “Earth, for example, is in the habitable zone of the Sun’s orbit.” This means that there might well be life on the planet.  
Would the mere existence of life on Gliese 581 g imply an inevitable submission of the human race to alien overlords? Or perhaps a renewed try at colonialism? Vali certainly does not think so. When I asked about the likelihood of alien life or human contact with the distant planet, his face twisted in dismissal. Obvious obstacles aside – the planet is over twenty light-years away – the places the role of this discovery in a more scientific light. Human curiosity about the nature of life – the conditions for its existence, its variations, and its very beginnings – is a driving force behind the field of astrobiology.

“Every living thing on Earth is based on the same principles of DNA, and the same limited diversity of atoms. These atoms were created under specific circumstances a long, long time ago. Would it not be fascinating then to get a glimpse of life at a different stage of development than us? It could well give us insight into how it was that life on our planet came to be,” explained Vali.  
Vali proposes that, whether or not interstellar life is based on the same principles as life on earth, finding it would have important implications. “It is possible that life on Gliese 581 g has DNA based on different elements than on Earth, and if this is so, our whole understanding of what life is would be challenged. However, if life on this planet is based on the same principles as on Earth, this is interesting also!,” he burst out, his enthusiasm becoming visible. “Then we would have evidence indicating that our type of life is the only type there is, imagine that!” 
Gliese 581 g was found with relatively little trouble, suggesting that there are millions other habitable planets to be discovered. For now though, Vali says “All we can do is imagine.”