Retaining Earth's Habitability Beyond the Life of the Sun

Abstract

The Earth is rare and large-scale interstellar travel may be unfeasible - instead of migrating to other solar systems, future civilisations on Earth may have to remain. However, left unchecked, the Earth's current habitability will end in one billion years. This paper investigates and conceptualises a set of megaengineering concepts required to safeguard against seven long-term threats to Earth's habitability: solar luminosity, solar engulfment, the end of tectonics, water loss, obliquity and rotation, object collision, and extra-system threats. Implementing and maintaining the set of safeguards would allow the Earth to remain habitable for 9.1 million billion years. This could be raised by an order of magnitude via lifting and moving solar photospheric mass. Compared with alternatives, advantages of the safeguards such as greater feasibility, lower requisite rate of energy production, and utilisation of economically viable space mining infrastructure may present remaining on Earth as a more attractive long-term survival strategy.