Stephen Hawking's thesis, wheelchair, Simpsons' script put on sale
British auction house Christie's has put on sale 22 belongings of late physicist Stephen Hawking. The articles include his PhD thesis, script of 'The Simpsons' episode where he lent his voice, and his earliest surviving wheelchair. Hawking's party invite for time travellers, released after the party, and a thumbprint-signed copy of 'A Brief History of Time' are also on sale.