Richard Dawkins is an evolutionary biologist who has built his entire career on analysing the wonders of space exploration - amongst other things - so if the location of Earth one day changed for no apparent reason, he would probably have a thing or two to say about it. As such, he briefly appeared during the Series 4 finale on a TV programme discussing the Earth's sudden movement and arrived at the conclusion that the planet had indeed moved to another part of the universe seeing as new constellations were now visible. If only the Doctor had been travelling with him, it would've saved everyone a lot of time.