- Author, Georgina Rannard
- Role, Science reporter
Scientists have discovered a cave on the moon for the first time.
At least 100 meters deep, it could be an ideal place for humans to build a permanent base, they say.
According to the researchers, this is just one of probably hundreds of caves hidden in the “underground, undiscovered world”.
Countries are racing to establish a permanent human presence on the moon, but they will need to protect astronauts from radiation, extreme temperatures and space weather.
Helen Sharman, Britain’s first female astronaut, told BBC News that the newly discovered cave looked like a good place for a base and suggested that people could potentially be living in lunar pits in 20-30 years.
But she said this cave is so deep that astronauts may have to abseil and use “jets or an elevator” to get out.
Lorenzo Bruzzone and Leonardo Carrer at the University of Trento in Italy found the cave by using radar to penetrate the opening of a pit on a rocky plain called Mare Tranquillitatis.
It is visible to the naked eye from Earth and is also where Apollo 11 landed in 1969.
The cave has a skylight on the surface of the moon that leads down to vertical and overhanging walls, and a sloping floor that could extend deeper underground.
It was made millions or billions of years ago when lava flowed to the moon and created a tunnel through the rock.
The closest equivalent on Earth would be the volcanic caves of Lanzarote in Spain, Professor Carrer explains, adding that the researchers visited these caves as part of their work.
“It’s really exciting. “When you make these discoveries and look at these images, you realize that you are the first person in human history to see this,” Professor Carrer said.
Once Professor Bruzzone and Professor Carrer understood how big the cave was, they realized it could be a good place for a lunar base.
“After all, life on Earth started in caves, so it makes sense that humans could live in them on the moon,” says Professor Carrer.
The cave has yet to be fully explored, but scientists hope that ground-based radars, cameras or even robots could be used to map it.
Scientists first realized that there were probably caves on the moon 50 years ago. Then in 2010, a camera on a mission called the Lunar Reconnaissance Orbiter captured images of pits that scientists thought might be cave entrances.
However, scientists did not know how deep the caves might be or whether they would collapse.
The work of Professors Bruzzone and Professor Carrera has now answered this question, although much more needs to be done to understand the full extent of the cave.
“We have very good images of the surface – up to 25cm resolution – we can see the Apollo landing sites – but we know nothing about what lies beneath the surface.” There are huge opportunities for discovery,” Francesco Sauro, coordinator of the European Space Agency’s Topical Team Planetary Caves, told BBC News.
The research may also help us explore caves on Mars in the future, he says.
This could open the door to finding evidence of life on Mars, because if it did exist, it would almost certainly be found in caves protected from the elements on the planet’s surface.
A moon cave may be useful to humans, but scientists also point out that it could help answer fundamental questions about the history of the moon and even our solar system.
The rocks inside the cave will not be as damaged or eroded by space weather, so they can provide an extensive geological record going back billions of years.
The research is published in the scientific journal Nature Astronomy.
Graphics by Gerry Fletcher