The moon has a secret underground CAVE: Scientists discover an empty lava tube beneath the lunar surface - and say it could be the perfect base for future settlers
- A pit on the moon has a 'subsurface cave conduit, tens of metres long'
- READ MORE: Hole spotted on Mars could be a gateway to ancient alien life
NASA and Elon Musk's SpaceX are planning to send humans back to the moon later this decade.
But on the lunar surface, astronauts will be exposed to potentially deadly cosmic rays and extreme temperatures.
Now, scientists may have found a suitable hiding place from these unforgiving conditions.
The experts in Italy say they have identified the first cave on the moon, which extends from inside a pit located in the Sea of Tranquility.
It could be a promising site for a lunar base, as it offers shelter from 'the harsh surface environment' and could support long-term human exploration of the moon.
The cave extends from inside Mare Tranquillitatis Pit (pictured) which is located at the moon's famous Sea of Tranquillity - close to where humans landed in 1969
The pit leads to a 'lava tube' - a natural conduit formerly occupied by flowing molten lava - which could provide shelter for astronauts
'These caves have been theorized for over 50 years, but it is the first time ever that we have demonstrated their existence,' said study author Lorenzo Bruzzone, professor at the University of Trento in Italy.
Since pits were first discovered on the moon by JAXA's SELENE spacecraft in 2009, scientists have wondered if they led to caves that could be explored or used as shelters.
There are more than 200 pits moon, around 16 of which are thought to be collapsed 'lava tubes' – natural conduits formerly occupied by flowing molten lava.
If the ceiling of a solidified lava tube collapses, it opens a pit – but whether these pits provide access to caves has long been uncertain.
The team focused on a roughly cylindrical pit in a part of the moon's northern hemisphere, known as the Sea of Tranquility, or Mare Tranquillitatis.
Tranquility Base, the location of the first manned landing on the moon in July 1969, is located in the south-western corner of the Sea of Tranquility.
Researchers focused on a roughly cylindrical 100-meter-deep depression, about the length and width of a football field, in an area of the moon, known as the Sea of Tranquillity or Mare Tranquillitatis (marked here with a red circle)
Researchers processed images from the Diviner Lunar Radiometer Experiment - a thermal camera on NASA's robotic Lunar Reconnaissance Orbiter (depicted here in space)
Mare Tranquillitatis Pit is the deepest known pit on the moon – an estimated depth of 328 feet (100 meters) and up to 377 feet (115 meters) across – about the length of a football pitch.
NASA's Lunar Reconnaissance Orbiter, which launched in 2009, captured radar data from the pit during a flyover more than a decade ago.
But the team have now reanalysed the radar data with new 'complex signal processing techniques'.
According to the findings, a portion of the radar reflections originating from the put can be identified as a 'subsurface cave conduit, tens of metres long'.
'Thanks to the analysis of the data we were able to create a model of a portion of the conduit,' said Leonardo Carrer, researcher at University of Trento.
'[We] have discovered radar reflections from the area of the pit that are best explained by an underground cave conduit.
'This discovery provides the first direct evidence of an accessible lava tube under the surface of the moon.'
Pictured, the researchers' illustration of the shape of the cave descending from Mare Tranquillitatis Pit
NASA's Lunar Reconnaissance Orbiter, which launched in 2009, captured radar data from the pit during a flyover more than a decade ago. But the team have now reanalysed the radar data with new 'complex signal processing techniques'
This new research has implications for the development of missions to the moon, where the environment is hostile to human life.
The moon is know for temperatures that are too extreme to sustain life – up to a scorching 260°F during the day and down to an icy -280°F at night.
But temperatures in a shady cave such as this are thought to be a 'comfortable' 63°F (17°C) – suggesting they could be the perfect locations for lunar base camps.
They could also provide shelter from cosmic rays and the thousands of meteorites that are thought to hit the moon every year.
It also opens up the possibility of other lunar pits leading to cave, which would give spacefarers more options when planning to establish settlements.
NASA hopes to develop a sustainable lunar exploration program starting from 2028. This artist's illustration shows what NASA's Artemis base camp could look like
Tranquility Base, the location of the first manned landing on the moon in July 1969, is located in the south-western corner of the Sea of Tranquility. Pictured is Buzz Aldrin during the Apollo 11 moon landing on July 20, 1969
Rather than going to the Sea of Tranquility, NASA's upcoming Artemis III mission plans to land a crew at the moon's south polar region in a SpaceX craft.
Eventually as part of its Artemis programme, NASA plans to have set up a base camp in the lunar south region by the end of this decade.
Building a lunar base in a pit or cave is not currently part of the official plan, but the study authors suggest it will be worth considering in the future.
'A complete survey of all known lunar pits would allow us to identify the most promising accesses for subsurface lunar exploration and provide information on the potential for installing human lunar base in environments protected from cosmic radiation and with stable temperatures,' they conclude.
Their new study has been published today in the journal Nature Astronomy.
