Jules Verne, Soviet Union, the Planets, the Internet -- Travel in the imagination

Sandi Toksvig asks whether a journey in the imagination will ever make up for the real thing. The fantastical voyages of French writer Jules Verne, a childhood spent dreaming of the 'free world' in the former Soviet Union, and richly researched planetary travels are just some of the journeys to be made without having to leave home. This week's guests: (1) Professor Tim Unwin, Professor of French at the Department of French, University of Bristol, and author of "Jules Verne: Journeys in Writing" (Liverpool University Press); (2) Ukraine-born Vitali Vitaliev, who began his writing career in the former Soviet Union with the satirical magazine "Krokodil", before the KGB forced him to defect in 1990, and author of "Dreams on Hitler's Couch" (Richard Cohen Books Ltd), "Borders Up!: Eastern Europe Through the Bottom of a Glass" (Scribner) and "Little Is the Light: Nostalgic Travels in the Mini States of Europe" (Pocket Books); (3) Dava Sobel, award-winning former science reporter for the "New York Times" and author of "The Planets: (Fourth Estate Ltd), "Longitude" (Perennial) and "Galileo's Daughter: A Drama of Science, Faith and Love (Fourth Estate Ltd); and (4) Harry Pearson, sports columnist for the "Guardian" and a travel writer in whose new book, "Around the World by Mouse: A Journey Round the Baltic" (Little Brown), he takes a trip round the world entirely by internet, visiting places about 100 miles apart in a line round the world.