Planet (Dr. Who's Time Tales)
A planet that was inhabitable for humans, with soil and atmosphere similar to Earth's, compatible gravity, but a surface five hundred times larger, was discovered by a space probe by the human civilisation which predated the "definitive" human civilisation that led up to the 20th century.
Having already advanced to "modern" levels of technology, this ancient civilisation became concerned with overpopulation, and, over a 130-year period, built a huge fleet of starships with which they performed a mass exodus from the Earth, intent on resettling on the new planet. It was expected that the planet could support the next thousand generations of humanity at their current growth rate and life expectancy. As far as they knew, only two humans remained on Earth, Adam and Eve. They resolved to lay the foundations for humanity to restart from scratch on the now-deserted Earth, deciding that they would not tell their descendants about the previous civilisation and its journey to the stars. (COMIC: Dr. Who's Time Tales)