Planets orbiting distant stars could have more abundant ecosystems packed with a more varied range of lifeforms than Earth, a new study has claimed.
A team from the University of Chicago analysed conditions on various exoplanets – the name for worlds outside our solar system – using special Nasa software which simulated climates and ‘ocean habitats’.
‘This is a surprising conclusion,’ said lead researcher Dr Stephanie Olson.
‘It shows us that conditions on some exoplanets with favourable ocean circulation patterns could be better suited to support life that is more abundant or more active than life on Earth.’
The search focused on planets which orbited at just the right distance from their host star so that water could exist on in a liquid form.
‘Nasa’s search for life in the Universe is focused on so-called Habitable Zone planets, which are worlds that have the potential for liquid water oceans,’ Dr Olson added.
‘But not all oceans are equally hospitable – and some oceans will be better places to live than others due to their global circulation patterns.
‘Life in Earth’s oceans depends on upwelling (upward flow) which returns nutrients from the dark depths of the ocean to the sunlit portions of the ocean where photosynthetic life lives.
‘More upwelling means more nutrient resupply, which means more biological activity. These are the conditions we need to look for on exoplanets.’
Dr Olson carefully modelled oceans on alien worlds to work out which had the ‘greatest capacity to host globally abundant and active life’.
This analysis revealed that the Earth we know and love might not actually have the best possible conditions for life.
“We have used an ocean circulation model to identify which planets will have the most efficient upwelling and thus offer particularly hospitable oceans,’ she went on.
‘We found that higher atmospheric density, slower rotation rates, and the presence of continents all yield higher upwelling rates.
‘A further implication is that Earth might not be optimally habitable–and life elsewhere may enjoy a planet that is even more hospitable than our own.
‘There will always be limitations to our technology, so life is almost certainly more common than “detectable” life.
‘This means that in our search for life in the Universe, we should target the subset of habitable planets that will be most favourable to large, globally active biospheres because those are the planets where life will be easiest to detect–and where non-detections will be most meaningful.’
The first exoplanet was discovered in 1992 and more than 4000 exoplanets have been spotted so far.