Vast areas of environment which support life are known to exist in the Earth’s subsurface but until now understanding of habitable environments on other planets has only taken into account their surfaces. The new model could vastly increase where we could expect to find life.
Sean McMahon from the University of Aberdeen’s School of Geosciences said: “Life ‘as we know it’ requires liquid water. Traditionally, planets have been considered ‘habitable’ if they are in the ‘Goldilocks zone’. They need to be not too close to their sun but also not too far away for liquid water to persist, rather than boiling or freezing, on the surface. However, we now know that many micro-organisms—perhaps half of all living things on Earth—reside deep in the rocky crust of the planet, not on the surface.”
Suns warm planet surfaces but heat also comes from planet interiors. Crust temperature increases with depth so planets that are too cold for liquid water on the surface may be sufficiently warm underground to support life.
Sean McMahon continues: “We have developed a new model to show how ‘Goldilocks zones’ can be calculated for underground water and hence life. Our model shows that habitable planets could be much more widespread than previously thought.”
Notes to Editors
Sean McMahon and Professor John Parnell are taking part in a press conference at the British Science Festival on Friday September 7 at 12.30pm
They are available for interview to journalists not attending the Festival. To arrange contact Kelly Potts/Jennifer Phillips on 01224 272960/273174.
An environment is ‘habitable’ if it is suitable for life as we know it. Habitable environments are not necessarily inhabited.
A ‘circumstellar habitable zone’ (CHZ or HZ) is a range of distances from a star. Planets that form from Earth-like materials within a star’s CHZ are able to maintain liquid water on their surfaces.
CHZs can be thought of as ‘Goldilocks Zones’ because Earth-like planets orbiting within them are neither too close to the star (too hot) nor too far away (too cold) for water to remain liquid on their surfaces. This concept has been well-established for over 20 years.
We introduce a new term, ‘subsurface-habitability zone’ (SSHZ) to denote the range of distances from a star within which planets are habitable at any depth below their surfaces up to a certain maximum. (For instance, one might speak of the “SSHZ for 2 km depth”, within which planets can support liquid water 2 km or less underground).
Notes for editors
1. About the British Science Festival
The British Science Festival is one of Europe’s largest science festivals and regularly attracts over 350 of the UK’s top scientists and speakers to discuss the latest developments in science with the public. Over 50,000 visitors regularly attend the talks, discussions and workshops. The Festival takes place at a different location each year and was last held in Aberdeen in 1963. The 2012 Festival will take place from 4 - 9 September hosted by the University of Aberdeen The 2012 British Science Festival in Aberdeen is organised by the British Science Association, the University of Aberdeen and TechFest-SetPoint .
For further information, visit www.britishscienceassociation.org/festival.
The principal sponsors of the British Science Festival are BP and Shell U.K. Limited.
2. The University of Aberdeen
Founded in 1495, the University of Aberdeen is the fifth oldest university in the UK, with a student population of around 16,000, and a large international community of students drawn from 120 different countries. The institution has an excellent reputation for teaching quality and research, and five Nobel Laureates are associated with the University.
3. About the British Science Association
The British Science Association is the UK's nationwide, open membership organisation which provides opportunities for people of all ages to learn about, discuss and challenge the sciences and their implications. Established in 1831, the British Science Association organises major initiatives across the UK, including National Science & Engineering Week, the annual British Science Festival, programmes of regional and local events, and an extensive programme for young people in schools and colleges. The Association also organises specific activities for the science communication community in the UK through its Science in Society programme. For more information, please visit http://www.britishscienceassociation.org/.
Issued by the Communications Team, Office of External Affairs, University of Aberdeen, King's College, Aberdeen. Tel: (01224) 272014.
Issued on: 07 September 2012
Ref: 268habitable plan
Contact: Kelly Potts