Giant Craters and Suspended Life: 5 Marvels and Mysteries on the Moon

The Artemis II mission that flew above the far side of the Moon is the farthest humans have ever been from Earth... but the comparatively close lunar surface still has marvels and mysteries for spacefaring adventurers. Let's take a look at:

• A New (and Disturbingly Large) Crater
• The Mare Orientale and the South Pole-Aitken Basin
• A Man-Made Double Crater... From a UFO?
• A Massive Pit Suitable for a Moon Base
• Assorted Biomatter, Sewage... and Tardigrades

A New (and Disturbingly Large) Crater

With almost no atmosphere to burn them up, the Moon is at the mercy of asteroids plunging into the surface. Even tiny bits of space debris can reach the ground, gradually changing the surface in a process called "impact gardening." But sometimes, these strikes have a much more dramatic effect.

In 2024, one such impact generated a crater around 225m wide and 43m deep. The shape of the crater suggests that it formed in fairly tough material (possibly solidified lava) which makes the impact even more impressive. Such powerful strikes are rare and researchers believe that they only happen around every 139 years.

The Mare Orientale and the South Pole-Aitken Basin

Impressive though the 2024 crater was, the crew of the Artemis II got to see a much larger and older example from the dark side of the Moon. Mare Orientale is a massive impact crater from billions of years ago during the "Late Heavy Bombardment" era... and is around 900km across. It's theorized that the impact of a 64km wide asteroid created a wave of material reaching around 100km above the surface.

Even this pales in comparison to the South Pole-Aiken Basin. Another feature from the Late Heavy Bombardment, the basin is over 2,500km across and on average, 10km deep. The impact may have been powerful enough to roll the Moon, and it's even been blamed for the differences in the geology of the near and far sides.

Another feature of the South Pole-Aiken Basin is a strange metal-rich mass beneath the surface. This mass is around five times the size of Island of Hawaiʻi, may be the remains of the asteroid responsible and actually drags the crater a further 0.8km down all by itself!

A Man-Made Double Crater... From a UFO?

It's not just forces of nature that hit the Moon - rocket debris can produce craters on the lunar landscape as well.

In 2021 the body of an unidentified rocket was observed on course for a lunar collision, with the actual impact occurring in March 4th 2022. Thanks to the advanced warning, NASA was able to produce before-and-after photos of the impact site... which display a unique double crater.

It's thought the double crater occurred due to the rocket debris being heavy at both ends... which is unusual, as discarded rocket bodies normally have a heavy "motor" at one end and a light empty fuel tank at the other.

It's been suggested that this UFO came from the Chinese Chang'e 5-T1 space mission... but China disputes that claim.

A Massive Pit Suitable for a Moon Base

If there's one thing the craters above tell us, it's that human attempts to make a base on the Moon will need some kind of protection from impacts. Even being near a strike can result in being pelted with high impact debris thrown clear of the blast.

While there's pretty much nothing one can do to stop strikes the size of the one that created Mare Orientale, lesser impacts could be avoided by living beneath the lunar surface - and it turns out that the Moon may have suitable of caves already in place.

One such possible site is a pit in the Mare Tranquillitatis region of the Moon. This pit is circular, around 100m across and at least 100m deep. It also holds tantalizing hints that it might extend further beneath the surface, possibly into a network of underground passages and galleries.

Pits like this could offer human explorers shelter from that hazards of the lunar surface - whether that be radiation, temperature or asteroid impact debris!

Assorted Biomatter, Sewage... and Tardigrades

There may not (or possibly may - who knows what we'll eventually find) be life on the Moon, but there's certainly biomatter.

According to Royal Museums Greenwich there ninety-six bags of human waste currently on the Moon, deposits left behind from lunar missions that didn't want to carry their waste home. Apparently researchers hope to retrieve the bags one day, to see what effect the prolonged lunar conditions have had on their contents.

The lunar surface also plays host to the ashes of Gene Shoemaker, a US geologist whose remains were flown to the Moon inside a specially-designed capsule.

Finally, there's the non-human passengers of the Beresheet lunar probe. This little unmanned lander was designed to carry a collection of Israeli history, a language primer, genetic samples and live tardigrades to the lunar surface, as well as sending back information to Earth.

Tardigrades (sometimes known as water-bears) are tough little creatures that can enter a state of suspended animation, drying themselves out and waiting for hazardous conditions to pass. They've proven able to survive the open vacuum of space in the past, can remain in this suspended animation for decades... and there's a chance they may have survived when Beresheet malfunctioned and crashed.

It's not likely that the tardigrades will ever come out of their sleep. There's no water to revive them (and they may not even have survived the crash of the lander) but the whole event has raised concerns amongst scientists about the ethics of contaminating extraterrestrial landscapes with terrestrial biomatter!

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Sources and Further Info:

• In a rare event, the moon got a massive new crater
• The Explosive History of Orientale Basin
• What is the South Pole-Aitken Basin?
• Mystery Solved!! Scientists Found Two New Craters on the Moon and Discovered a New Mystery
• Cave discovered on Moon could be home for humans
• The strange things we've left on the Moon
• Tardigrades: 'Water bears' stuck on the moon after crash