Curiosity’s Kaguya finds Moon cave

A Moon cave is real here — but the “today” part is mostly social-media timing, not a fresh space discovery. The object in question is the Marius Hills pit, a skylight-like hole in an old volcanic region of the Moon. Japan’s Kaguya orbiter spotted it years ago, and later work used radar to argue that the opening may connect to a much larger underground lava tube. So the news hook is a resurfaced claim, but the science underneath it is solid. ### What did Kaguya actually see? Kaguya — also called SELENE — imaged a deep hole in the Marius Hills region, one of the Moon’s most volcanic-looking terrains. This wasn’t just a random crater. The hole sits in the middle of a sinuous rille, which is exactly the kind of place where ancient lava channels and lava tubes show up. That made scientists suspect they were looking at a skylight — basically a collapse opening into a buried tunnel. (isas.jaxa.jp) ### Is this a brand-new discovery? No. The pit itself was reported in 2009 from Kaguya image data, and the bigger “there may be an intact tube under this” result was announced in October 2017. What happened this week is that the finding got repackaged and recirculated online as if it had just been found. The cave is old news in timeline terms, but not fake news in substance. (lroc.im-ldi.com) ### How big is the opening? The opening is not enormous by cave-mouth standards, but it is big enough to matter. High-resolution Lunar Reconnaissance Orbiter images later measured the Marius Hills pit at roughly 58 by 49 meters and about 40 meters deep. Older estimates put it around 65 meters across, which is why both numbers float around online. The mismatch is just different measurements from different imaging passes, not a contradiction. (isas.jaxa.jp) ### Why do scientists think there’s a tunnel below? Because Kaguya didn’t stop at pictures. Its Lunar Radar Sounder looked below the surface near the pit and picked up echo patterns consistent with a subsurface void. The 2017 analysis argued that these signals fit an intact lava tube running along the rille, and JAXA summarized the result as a tube about 50 km long. That is the part that turned a cool hole into a serious habitat candidate. (lroc.im-ldi.com) ### What is a lunar lava tube, anyway? It’s the hollow plumbing left behind after a lava flow drains away. Earth has them too, but the Moon can preserve much larger ones because lunar gravity is weaker and there’s no weather chewing them apart. Think of the skylight as a broken patch in the roof — not the cave itself, but a window into it. That’s why one pit can imply a much bigger hidden space. (isas.jaxa.jp) ### Why do people care so much about caves on the Moon? Because the lunar surface is nasty. Radiation is high, micrometeorites are a constant risk, and temperatures swing hard between lunar day and night. A lava tube could give astronauts and instruments natural shielding without hauling tons of building material from Earth. It could also preserve ancient rock, gases, and volcanic textures in a more pristine state than the blasted surface does. (lroc.im-ldi.com) ### Is this definitely a future Moon base? Not yet. “Possible habitat” is not the same thing as “ready-made base.” Engineers still need better maps, structural data, access plans, and a way to get people and equipment safely in and out. But as a target for future robotic scouting, Marius Hills keeps showing up for a reason — it combines an actual opening with evidence for a much larger void below. (isas.jaxa.jp) ### Bottom line? The viral post points to a real lunar feature, but it is reviving a discovery chain from 2009 and 2017, not announcing a fresh one on May 12, 2026. Still, the underlying idea is the exciting part — Kaguya found one of the best leads yet that the Moon may hide huge natural shelters underground. (isas.jaxa.jp)