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Did a mega-collision alter Venus?

25 February 2008

A mega-collision between two large embryonic planets could have created Venus as we know it, according to a new paper by a Cardiff University scientist.

Venus is a sister planet to Earth. It is nearly the same size and density yet it has a surface temperature of 720 K, an atmosphere dominated by carbon dioxide and no evidence of oceans or ridges. It has been described as "Earth’s evil twin".

Dr Huw Davies of the School of Earth and Ocean Sciences, argues that a mega-collision could explain these differences. In particular the collision could explain why the interior of Venus is dry, the odd rotation of the planet and the carbon dioxide atmosphere.

Dr Davies of the School of Earth and Ocean Sciences said: "A collision theory has been explored by scientists previously but was abandoned as the planet Venus has no moon usually expected from such an impact. However, a mega-impact could have created Venus, since the head-on collision I propose does not produce a moon."

The hot ball of gas and liquid that would result immediately following the collision would allow iron to react away the water. Significant suggested consequences of a dry planet include the lack of plate tectonics, continents and life on Venus.

Dr Davies’ research is published in the journal Earth and Planetary Science Letters and reported in New Scientist magazine.


Notes to Editors:

1. Cardiff School of Earth and Ocean Sciences
Cardiff University’s School of Earth and Ocean Sciences is one of the top geoscience units in the UK, rated 5A in most research independent Research Assessment Exercise. It is a large, international research school with more than 30 leading international research scientists, currently including two Fellows of the Royal Society. The postgraduate research school currently numbers about 35 students studying a diverse range of research problems. These researchers are addressing some of the most significant research themes in world science at the moment, including global change, the origin and evolution of life, environmental science, natural resource exploration, and the evolution of Earth and planets.

2. Cardiff University
Cardiff University is recognised in independent government assessments as one of Britain’s leading teaching and research universities. It is also ranked as one of the world’s top 100 universities by the Times Higher Education Supplement (THES).
2008 marks the 125th anniversary of Cardiff University having been founded by Royal Charter in 1883. Today the University combines impressive modern facilities and a dynamic approach to teaching and research. The University’s breadth of expertise in research and research-led teaching encompasses: the humanities; the natural, physical, health, life and social sciences; engineering and technology; preparation for a wide range of professions; and a longstanding commitment to lifelong learning.
Cardiff is a member of the Russell Group of the UK’s leading research universities.
Visit the University website at:

Further Information:

Dr Huw Davies
School of Earth and Ocean Sciences
Cardiff University
Tel: 02920 875182

Emma Darling / Victoria Dando
Public Relations
Cardiff University
Tel: 02920 874499 / 879074