Prof Paul Davies addresses the crowd at this year’s Cheltenham Science Festival. Image Credit: Kieron Allen
Exoplanet Explorers was the title of yesterday’s talk by Royal Society University Research Fellow Dr Giovanni Tinetti, renowned astrobiologist Professor Paul Davies and Met Office oceanographer turned astrophysicist Dr David Acreman.
Held in the Winston Crucible, one of six temporary lecture theatres at this year’s Cheltenham Science Festival, the lecture aimed to cover all the latest research into exoplanets.
Dr Tinetti began with an overview of how the current research into exoplanets began – prior to 1995 none were known to exist, now scientist predict that at least 100 billion reside in our Galaxy alone.
She continued by explaining how these far flung bodies were categorised and finally the methods used by space scopes, like Kepler and the now defunct COROT mission to find them.
Professor Davies discussed the controversial ideas on the existence of ‘alien’ life, informing a captivated audience about the ‘shadow biosphere’ theory – the idea that life, but not as we know it, could still exist on planet Earth today having evolved independently.
Dr Acreman took the discussion in a completely different direction with an explanation of how he and his team reconstruct the climates and atmospheres on exoplanets.
As well as studying the climate on exoplanets, Dr Acreman and his team at the University of Exeter’s Astrophysics group look at how these planets are formed.
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They have adopted an ‘outside in’ approach, starting with the formation of stars, to the emergence of planets and finally to the state of their atmospheres.
“One of the areas we look at is the formation of planetary systems,” he said.
“When a star is formed it has a disc of gas and dust around it and that’s the material that the planets are made from, if you want to understand planet formation you need to understand discs around young stars.”
Acreman’s team use different modeling techniques to study the planet forming process.
“We can put these into three broad categories,” said Dr Acreman.
“There’s the TORUS code (The AMR radiation transport and hydrodynamics code – like all the models used, a numerical algorithm) and that has a lot to do with studying how radiation moves through matter, if you want to know what the disc around your young star is going to look like that’s the tool we use for doing that.”
“The second method is called smooth particle hydrodynamics which is used to model the discs themselves, this looks at how you might get a planet sized objet forming out of this gas and dust and how the planet can pick up the material from its surroundings and grow in size.”
Dr Acreman then went on to explain the Met Office model, it is this model that is used to predict the climate on exoplanets.
“Essentially what it’s doing is telling us what happens when you’ve got a body that’s roughly circular, rotating and with some kind of gas atmosphere around the outside that’s heated by a star.
“It’s what we have on Earth and as far as we know the physics are the same across the Universe, so we can use similar techniques to model exoplanets.”
The Met Office model, used to predict weather on Earth takes into account the fact that the atmosphere is split into areas of high and low pressure, that it is warmer in some areas than others and that our rotating Earth has an effect on the direction of wind (the image above represents the climate on an exoplanet using these constraints).
This year’s Cheltenham Science Festival runs from 4-9 June 2013.