LONDON: Lava tubes - underground caves created by volcanic activity - could provide protected habitats large enough to house streets or even towns on the Moon and Mars, scientists say.
Lava tubes are found in many volcanic areas on Earth, including Hawaii, Iceland, North Queensland in Australia, Sicily and the Galapagos islands.
Underground networks of tubes can reach up to 65 kilometres.
Space missions have also observed chains of collapsed pits and 'skylights' on the Moon and Mars that have been interpreted as evidence of lava tubes.
Researchers from the University of Padova and the University of Bologna in Italy have carried out the first systematic comparison of lava tube candidates on the Earth, Moon and Mars, based on high-resolution Digital Terrain Models (DTM) created using data from spacecraft instrumentation.
"The comparison of terrestrial, lunar and martian examples shows that, as you might expect, gravity has a big effect on the size of lava tubes," said Riccardo Pozzobon, of the University of Padova.