Scientists have revealed the full technical details of their discovery of vast reservoirs of ice beneath the Martian surface. So much ice has been found in the polar regions that if it were to melt it would deluge the planet. The ice may stretch far underground to regions where it is warm, raising the possibility of warm caverns of meltwater in which scientists hesitantly speculate conditions could be suitable for life. But they caution that we may never know until we have rock and ice samples returned to Earth by an unmanned probe for analysis.