since moved to the National University of Singapore.">

NASA one step closer to finding aliens

By Steve Pointing 16/04/2015

I have been fortunate enough to work closely with NASA’s Ames Research Center for over ten years.  They are the world’s leading astrobiology research institution, and have been responsible for most of the major advances in this field.  This week has been massive for NASA for two reasons: The discovery of conditions for liquid water on Mars and a very bold statement from their chief scientist Ellen Storfan that NASA would demonstrate evidence life on another planet by 2025.
I explain more detail about both items this week on the Paul Henry Show and also on my ‘Dear Science’ radio broadcast on BFM.
What has prompted NASA to make this bold prediction?
  • NASA now has a thorough understanding of what makes a planet ‘habitable’, so they know where to look – a key advantage in the vastness of space!
  • Recent discoveries have revealed the essential ‘ingredients’ for life (water and organic chemicals) are far more widespread in the universe than previously thought.

Where should we be looking for aliens?
  • NASA is exploring the surface of our closest planetary neighbour Mars, and has plans to also investigate one of Jupiter’s moons, Europa.  Mars was chosen because in the not-too distant past the planet was much warmer and wetter, with a climate similar to Antarctica’s McMurdo Dry Valleys today. Europa supports a vast liquid water ocean beneath its icy surface, and so may offer habitats similar to those at deep-sea hydrothermal vents here on Earth.
  • Further afield, the Kepler space telescope has identified thousands of earth-like planets in distant solar systems that occupy the ‘habitable zone’, an orbit just the right distance from a star to allow liquid water to exist.

What would alien life be like?
  • Any aliens on Mars or Europa would likely be microorganisms.  The extreme environmental stress they would face, and the scarcity of organic ‘food’ means that they would also likely be autotrophic – obtaining their energy from sunlight or inorganic compounds, and their carbon from fixing carbon dioxide (as plants do here on Earth). We know from looking at similar environments on Earth that they would likely be single celled bacteria or archaea.
  • If life has evolved on planets in another solar system, it would be adapted to the conditions there – different gravity, radiation, oxygen availability and other factors mean that their phenotype could be unlike anything we have encountered.  Having said this, the parsimony that drives evolution of biochemical processes means that basic biomolecules and metabolism may share many similarities with Earth-bound life.

How do we detect these aliens?
  • Astrobiologists require a ‘smoking gun’ of irrefutable evidence, previous over-confident claims of ‘proof’ for alien life have not helped credibility in this field – recall US President Bill Clinton in 1996 announcing to the world that evidence for life in a Martian meteorite had been found, but now widely believed to be an abiotic artefact.
  • Future Mars landers need to search for chemical signatures that are exclusively biogenic – complex organic molecules like DNA, chlorophyll or proteins that can only be synthesised by living systems.
  • The Kepler space telescope is finding a staggering number of potentially Earth-like planets in other solar systems.  This is because compared to earlier telescopes that largely could resolve only large gas giant planets, Kepler can identify relatively small planets of similar mass to Earth.  At this stage evidence for life on these would be indirect, for example due to gas disequilibrium in their atmosphere.

Is there any chance that we might encounter intelligent alien life?
  • This really depends on your viewpoint, if you are take an anthropocentric view you may see humanity as a unique ‘occurrence’ in the universe, but conversely if you favour the mediocrity view then you may feel life is something that can arise frequently in our vast universe.
  • Current efforts to make humanity known to aliens are fairly trivial. The SETI programme monitors radio waves but they travel relatively slowly, and so an alien broadcast might reach us long after their civilisation had crumbled. Similarly our own radio emissions have travelled only a small distance into space (about 50 light years) and so we are not making ourselves very easy to find.  The Voyager spacecraft launched in the 1970’s is the first man-made item to leave our solar system, but that is a single and very small sign that we are here!

What does all this mean for faith and religion?
  • Scientists are frequently atheists, and many people of faith reject scientific notions of the evolution of life. I find it a little amusing that many scientists reject religion and the notion of an omniscient entity (God) despite having absolute ‘faith’ that before the Big Bang there was an indefinable ‘nothing’. Finding proof of life on other planets might help to bring scientists and people of faith together in seeking to redefine our place in the universe. 
  • Interestingly Pope Francis stated in 2014 that he would be willing to baptise a Martian, it might be a win-win for faith and science if we do find alien life!