Scientists from JAXA, the Japanese space agency, say they have discovered an enormous underground cave on the moon.

The discovery is exciting because the cave could provide a safe place for astronauts to live and work on future missions to the moon.

In 2009, a lunar probe launched by JAXA sent back images of the cave’s entrance. The probe used radar to determine the underground structures below the entrance and sent the information back to JAXA to be analyzed.

In October, JAXA announced that there appears to be a cavern about 50 kilometres (31 miles) long and 100 metres (328 feet) wide leading from the opening.

Scientists say the cave could make an ideal base for astronauts. It would protect the astronauts and their equipment from the extreme heat and cold on the moon’s surface. It would also help keep them safe from micrometeorites (tiny particles of space dust) that land on the moon, and from the harmful rays of the sun.