Enlarge / Modeling has shown how material ejected from the Earth by a massive collision could have formed the Moon. Now the models are being used to look at what happened inside the Earth. (credit: NASA )

Seismic waves created by earthquakes as they travel through the planet's interior change speed and direction as they move through different materials. Things like rock type, density, and temperature all alter the travel of these waves, allowing scientists to gradually build up a picture of the Earth's crust and mantle, spotting things like the rise of plumes of hot mantle material, as well as the colder remains of tectonic plates that dropped off the surface of the Earth long ago.

There are some things that show up in these images, however, that aren't easy to explain. Deep in the Earth's mantle there are two regions where seismic waves slow down, termed large low-velocity provinces. This slowdown is consistent with the materials being higher density, so it's not really a surprise that they're sitting near the core. But that doesn't explain why there are two distinct regions of them or why they appear to contain material that has been there since the formation of the Solar System.

Now, a team of scientists has tied the two regions' existence back to a catastrophic event that happened early in our Solar System's history: a giant collision with a Mars-sized planet that ultimately created our Moon.

Enlarge (credit: Master/Getty )

The Moon is slated to be our next frontier. When Artemis 3 takes off (tentatively) near the end of 2025, it will be the first mission since the Apollo era to land humans on our satellite. By then, there might be a new way to get around on the Moon’s gray dust, which could at least mitigate damage from sharp particles of lunar regolith.

An international team of researchers with the ESA PAVER project has figured out a way to melt Moondust—or at least an ESA-developed stimulant for it—with lasers. The researchers fired laser beams at lunar soil to create interlocking pavers that could be used to construct paved roads and landing pads. The hardened molten regolith is tough enough to withstand the weight of rovers and other spacecraft with minimal dust kickup, and it could all be made right there on the Moon.

“This technology is envisioned to play a major role in the first phase (survivability) of lunar infrastructure and base development, and over time to contribute to all phases of lunar exploration,” the researchers said in a study recently published in Scientific Reports .

Enlarge / The first stage for ULA's Vulcan rocket was lifted onto its launch platform at Cape Canaveral in January. (credit: United Launch Alliance )

Three days at Christmastime will be the final chance for United Launch Alliance to get its new Vulcan rocket off the ground this year, the company's chief executive announced Tuesday.

Still waiting for delivery of an upper stage and a final round of qualification testing following a test mishap earlier this year , Tory Bruno, ULA's CEO, told CNBC on Tuesday that the Vulcan rocket's first demonstration flight is scheduled for launch December 24. There are two backup launch dates available December 25 and 26, or else the launch will have to wait until January.

There are threats to this schedule, but ULA officials were confident enough in the timeline to publicly disclose the launch date Tuesday. They have also told Astrobotic, which is flying its first commercial Moon cargo lander on the inaugural Vulcan rocket, to ship its spacecraft from the company's Pittsburgh headquarters to Florida in anticipation of a December launch.

Enlarge / The Moon rises over Tindari, Sicily. (credit: Dario Giannobile)

Welcome to the Daily Telescope . There is a little too much darkness in this world and not enough light; a little too much pseudoscience and not enough science. We'll let other publications offer you a daily horoscope. At Ars Technica, we're going to take a different route, finding inspiration from very real images of a universe that is filled with stars and wonder.

Good morning. It is October 24, and today's image features an amazing shot of the Moon over a sanctuary in Sicily. It was captured by Dario Giannobile , a talented Italian astrophotographer.

This is a brilliant shot of the Moon, with the light from Earth shining on about 75 percent of the lunar surface and the remainder brightly lit by the Sun. The Moon is seen above the Santuario della Madonna Nera (Sanctuary of the Black Madonna) in Tindari, a small town on the northern coast of Sicily.

Enlarge / Astrobotic's first lunar lander, named Peregrine, is complete and ready for shipment to the launch site at Cape Canaveral, Florida. (credit: Astrobotic )

Within a few months, NASA may celebrate the first successful landing of an American spacecraft on the Moon in more than 50 years. This would be an immense confidence boost for commercial startups with an eye on the nascent market for lunar missions. It would also signal to NASA that it can rely on commercial companies for foundational elements of the agency's Artemis program to return humans to the Moon.

Realistically, there's also a chance that the first two commercial robotic lunar landing missions may miss the mark. One or both could crash on the lunar surface or otherwise falter along the journey from the Earth to the Moon. This wouldn't be a disaster. NASA officials have smartly set low expectations for these early commercial lunar missions, but these first landers are several years late, and a series of failures would inevitably raise questions about the program's future.

Five years after NASA started the Commercial Lunar Payload Services (CLPS) program , two companies finally have lunar landers ready for final launch preparations. Astrobotic's robotic Moon lander, Peregrine, has been in storage since March at the company's headquarters in Pittsburgh. This week, Intuitive Machines showed off its completed Nova-C lander to Ars in Houston.

Enlarge / A view of India's Vikram lander taken Wednesday from the Pragyan rover. (credit: ISRO )

It's been more than a week since India's Chandrayaan 3 mission landed on the Moon, and it's a good time to assess where the world's most populous nation stands relative to other global other space powers.

The successful arrival of the Chandrayaan 3 mission's Vikram lander on the Moon made India the first country besides China to achieve a soft landing on the lunar surface since 1976, following a series of failed landings by private organizations and India itself four years ago. And it made India just the fourth nation overall to achieve this feat.

Since the landing of Chandrayaan 3 on August 23, India has released some early findings from the lander and its mobile rover, named Pragyan, along with photos of the vehicles exploring the Moon's alien charcoal-color landscape.

Enlarge / The first view from the Moon's surface captured by Chandrayaan 3's Vikram lander, showing the shadow of one of the craft's landing legs. (credit: ISRO )

A robotic landing craft from India successfully touched down in the southern polar region of the Moon on Wednesday, making the rising space power the fourth nation to achieve a soft landing on the lunar surface.

The Vikram lander from India's Chandrayaan 3 mission landed at approximately 8:33 am EDT (12:33 UTC) after a nail-biting final descent broadcast to the world by India's space agency.

Confirmation of the successful landing triggered a celebration across India, both inside and outside the mission control center in Bangalore. Chandrayaan 3 ends a 47-year drought in successful lunar landings by any country outside China, which has placed three probes on the Moon's surface, including one on the lunar far side, since 2013.

Enlarge / India's Chandrayaan 3 lander stands about 2 meters, or a little more than 6 feet, in height. (credit: ISRO )

India's Chandrayaan 3 spacecraft is setting up for a final descent to the surface of the Moon on Wednesday, four days after Russia's Luna 25 lander cratered following a botched engine burn.

If all goes according to plan, the Chandrayaan 3 lander—named Vikram—will settle softly onto the lunar surface at 8:34 am EDT (12:34 UTC) Wednesday, redeeming India's failed landing attempt on the Chandrayaan 2 mission in 2019.

But for the last 47 years, reaching the Moon's surface in one piece has proven to be an impossible task for any landing craft that wasn't built in China. Since 2013, China has racked up three successful landings with its robotic space missions, including the first controlled touchdown on the Moon's far side and an ambitious sample return mission in 2020 .