YOU ARE HERE: Home > News & Press > Oceans galore: new study suggests most habitable planets may lack dry land

I want information on:

Information for:

NEWS & PRESS

Oceans galore: new study suggests most habitable planets may lack dry land

Last Updated on Thursday, 20 April 2017 10:01
Published on Thursday, 20 April 2017 09:58

When it comes to exploring exoplanets, it may be wise to take a snorkel along. A new study, published in a paper in the journal Monthly Notices of the Royal Astronomical Society, has used a statistical model to predict that most habitable planets may be dominated by oceans spanning over 90% of their surface area.

 

The author of the study, Dr Fergus Simpson of the Institute of Cosmos Sciences at the University of Barcelona, has constructed a statistical model – based on Bayesian probability – to predict the division between land and water on habitable exoplanets.

 

For a planetary surface to boast extensive areas of both land and water, a delicate balance must be struck between the volume of water it retains over time, and how much space it has to store it in its oceanic basins. Both of these quantities may vary substantially across the full spectrum of water-bearing worlds, and why the Earth’s values are so well balanced is an unresolved and long-standing conundrum.

 

thumb waterworld earthContinents on other habitable worlds may struggle to break above sea level, like much of Europe in this illustration, representing Earth with an estimated 80% ocean coverage. © Antartis / Depositphotos.com. Click for a larger imageSimpson’s model predicts that most habitable planets are dominated by oceans spanning over 90% of their surface area. This conclusion is reached because the Earth itself is very close to being a so-called ‘waterworld’ - a world where all land is immersed under a single ocean.

 

“A scenario in which the Earth holds less water than most other habitable planets would be consistent with results from simulations, and could help explain why some planets have been found to be a bit less dense than we expected,” explains Simpson.

 

In the new work, Simpson finds that the Earth’s finely balanced oceans may be a consequence of the anthropic principle – more often used in a cosmological context - which accounts for how our observations of the Universe are influenced by the requirement for the formation of sentient life.

 

“Based on the Earth’s ocean coverage of 71%, we find substantial evidence supporting the hypothesis that anthropic selection effects are at work,” comments Simpson.

 

To test the statistical model Simpson has taken feedback mechanisms into account, such as the deep water cycle, and erosion and deposition processes. He also proposes a statistical approximation to determine the diminishing habitable land area for planets with smaller oceans, as they become increasingly dominated by deserts.

 

Why did we evolve on this planet and not on one of the billions of other habitable worlds? In this study Simpson suggests the answer could be linked to a selection effect involving the balance between land and water.

 

“Our understanding of the development of life may be far from complete, but it is not so dire that we must adhere to the conventional approximation that all habitable planets have an equal chance of hosting intelligent life,” Simpson concludes.

 


Media contacts

 

Dr Robert Massey
Royal Astronomical Society
Tel: +44 (0)20 7292 3979
Mob: +44 (0)7802 877 699
This email address is being protected from spambots. You need JavaScript enabled to view it.

 

Dr Morgan Hollis
Royal Astronomical Society
Tel: +44 (0)20 7292 3972
This email address is being protected from spambots. You need JavaScript enabled to view it.

 


Science contact

 

Dr Fergus Simpson
Institute of Cosmos Sciences
University of Barcelona
Mob: +44 7708 988 121
This email address is being protected from spambots. You need JavaScript enabled to view it.

 


Images and captions


Animation showing how the Earth would appear as the amount of water in its oceans increases. Only a narrow window exists in which large areas of both land and water are present. Credit: F. Simpson


Continents on other habitable worlds may struggle to break above sea level, like much of Europe in this illustration, representing Earth with an estimated 80% ocean coverage. © Antartis / Depositphotos.com

 


Further information

 

The new work appears in “Bayesian evidence for the prevalence of waterworlds”, F. Simpson, Monthly Notices of the Royal Astronomical Society (2017). A copy of the paper is available from http://doi.org/10.1093/mnras/stx516

 


Notes for editors

 

The Royal Astronomical Society (RAS, www.ras.org.uk), founded in 1820, encourages and promotes the study of astronomy, solar-system science, geophysics and closely related branches of science. The RAS organizes scientific meetings, publishes international research and review journals, recognizes outstanding achievements by the award of medals and prizes, maintains an extensive library, supports education through grants and outreach activities and represents UK astronomy nationally and internationally. Its more than 4,000 members (Fellows), a third based overseas, include scientific researchers in universities, observatories and laboratories as well as historians of astronomy and others.

 

The RAS accepts papers for its journals based on the principle of peer review, in which fellow experts on the editorial boards accept the paper as worth considering. The Society issues press releases based on a similar principle, but the organisations and scientists concerned have overall responsibility for their content.

 

T: https://twitter.com/royalastrosoc
F: https://www.facebook.com/RoyalAstroSoc/