Geocentric model and planets were holes in invisible wheels surrounding Earth; through the holes, humans could see concealed fire. About the same time, Pythagoras thought that the Earth was a sphere (in accordance with observations of eclipses), but not at the center; they believed that it was in motion around an unseen fire. Later these views were combined, so most educated Greeks from the 4th century BC on thought that the Earth was a sphere at the center of the universe. In the 4th century BC, two influential Greek philosophers, Plato and his student Aristotle, wrote works based on the geocentric model.
Pension term assurance effectively stopped any more new PTA business being written. Those with existing policies were allowed to keep them running. Despite what the name might suggest, Pension Term Assurance did not have to form part of a pension - it merely needed to be taken out at the same time as a new pension was set up. Pension term assurance Pension Term Assurance (PTA) was a form of life insurance available within the United Kingdom. Although PTA had been available for several years, it only became mainstream when changes were made to pension legislation on "A Day", 6 April 2006. Following