A long time ago, billions of years in fact, in a galaxy we're all quite familiar with, the molten core of our moon began bursting with violent flows of basaltic lava that coursed beneath the gentle gradients of the lunar mare to form winding underground tunnels. And ever since humans first glimpsed one in 2009, we've been eager to do what all warm-blooded mammals do: burrow. That's why a NASA robot has gone spelunking in Hawaii.
A little robot called Moon Diver is exploring ancient Hawaiian lava tubes with NASA scientists who hope to understand similar celestial structures.
"We have three science teams here all week, testing different types of instruments and gathering data on the size and shape of the lava tube, the chemistry and mineralogy of the rocks, and the gases present," NASA tweeted Tuesday.
The similarity between Hawaiian lava tubes and caves on the moon is also why the European Space Agency (ESA) needs cartographers.
"They could also be an interesting option as long-term shelter for future human visitors to the moon," said Francesco Sauro, the director of the ESA's PANGEA planetary geology astronaut training. "They would shield astronauts from cosmic radiation and micrometeorites and possibly provide access to icy water and other resources trapped underground."
Sauro and the ESA on Wednesday invited the world to join their quest to map out and explore moon caves.
It's unlikely NASA's Moon Diver will get a shot at the lunar caves -- or that a map-making astronaut will chart one first hand -- any time soon. But after so many billions of years, what's a few more decades?