[DB 1507 (34); OAB 23] The claim is that Poynting-Robertson drag, an effect which causes interplanetary dust to fall into the Sun, should have swept the solar system clear of debris if it were old. In reality, the debris is constantly replenished by pieces of comets stripped off by solar wind, as well as other sources. This replenishing source is summarily dismissed by the authors of this claim however, who reason that comets cannot have existed for billions of years. See previous claim (Maximum Life of Comets).