since moved to the National University of Singapore.">

Astrobiology takes centre stage

By Steve Pointing 12/12/2014

Astrobiologists are all a flutter today as the Rosetta team announced their first detailed scientific analysis of the comet Philae (  Their analysis of water isotopes showed that the composition varied significantly from those found in water on our planet today – and this debunks a popular theory in astrobiology that comets were the source of water on a prebiotic earth.  Attention now turns to asteroids (these are rocky bodies as opposed to comets that are made largely of ice) as the likely source of earth’s water.  Whilst most asteroids in our solar system today have little or no water, this is because it has sublimated away over millennia, and it is widely believed they once comprised a significant water reservoir in our solar system.  Importantly this was also at the time earth was experiencing a high frequency of impacts and so this explanation is gaining traction.  For me this is also very exciting because the estimated timing of the largest part of this water deposition on earth (from around 3.8Ga) is very close to the estimated origin of life on earth (somewhere between 3.8-3.5Ga) – and so it suggests that life either evolved very soon after favourable conditions emerged or that perhaps some of the building blocks of life came ‘pre-assembled’ along with this water from space.  Simple organic compounds are widespread in space, but evidence for more complex organic compounds or even viable cells is lacking. This notion relates to the theory of ‘panspermia’ that postulates life in the universe has made inter-planetary leaps, although it is not supported by empirical evidence.
Astrobiology is also gaining momentum and popularity in New Zealand.  It addresses what are arguably the biggest questions in science – where do we come from? Are we alone? Where are we going? (  The multidisciplinary nature of astrobiology lends itself well to integrative science learning – and this is the rationale behind the forthcoming NASA Spaceward Bound expedition to be held in Taupo next month (  This event will bring together NASA scientists, university researchers and schoolteachers for a unique learning experience.  It is the first time that New Zealand has hosted a Spaceward Bound event, which are hugely popular around the world – I have been involved with previous Spaceward Bound expeditions and they are a great way to connect tertiary and secondary educators, and explore novel platforms for science learning.  Our kiwi Spaceward Bound is being organised by Haritina Mogosanu, who is well known in Aotearoa for her passion in astronomy – and I am really looking forward to being part of her vision when we head to Taupo to show how life in hot pools and other extreme habitats can be used to illustrate how life began on earth, and also test some cool NASA gadgets used in exploring our closest neighbour – Mars.