Rust, a modern and notably more memory-safe language than C, once seemed like it was on a steady, calm, and gradual approach into the Linux kernel.

In 2021, Linux kernel leaders, like founder and leader Linus Torvalds himself, were impressed with the language but had a "wait and see" approach. Rust for Linux gained supporters and momentum, and in October 2022, Torvalds approved a pull request adding support for Rust code in the kernel.

By late 2024, however, Rust enthusiasts were frustrated with stalls and blocks on their efforts, with the Rust for Linux lead quitting over "nontechnical nonsense." Torvalds said at the time that he understood it was slow, but that "old-time kernel developers are used to C" and "not exactly excited about having to learn a new language." Still, this could be considered a normal amount of open source debate.

But over the last two months, things in one section of the Linux Kernel Mailing List have gotten tense and may now be heading toward resolution—albeit one that Torvalds does not think "needs to be all that black-and-white." Greg Kroah-Hartman, another long-time leader, largely agrees: Rust can and should enter the kernel, but nobody will be forced to deal with it if they want to keep working on more than 20 years of C code.

Previously, on Rust of Our Lives

Earlier this month, Hector Martin, the lead of the Asahi Linux project, resigned from the list of Linux maintainers while also departing the Asahi project, citing burnout and frustration with roadblocks to implementing Rust in the kernel. Rust, Martin maintained, was essential to doing the kind of driver work necessary to crafting efficient and secure drivers for Apple's newest chipsets. Christoph Hellwig, maintainer of the Direct Memory Access (DMA) API, was opposed to Rust code in his section on the grounds that a cross-language codebase was painful to maintain.

Torvalds, considered the "benevolent dictator for life" of the Linux kernel he launched in 1991, at first critiqued Martin for taking his issues to social media and not being tolerant enough of the kernel process. "How about you accept that maybe the problem is you," Torvalds wrote.

But then Hellwig posted a longer missive, outlining his opposition to Rust bindings—or translations of Rust libraries that can work with equivalents in C—and continuing with his prior comparison of such multi-language allowances to "cancer." "I'd like to understand what the goal of this Rust "experiment" is: If we want to fix existing issues with memory safety we need to do that for existing code and find ways to retrofit it," Hellwig wrote. He also stated that Torvalds had "in private said that he absolutely is going to merge Rust code over a maintainers [sic] objection."

A two-way “wall of protection”

Torvalds' response from Thursday does offer some clarification on Rust bindings in the kernel, but also on what die-hard C coders can and cannot control.

Maintainers like Hellwig who do not want to integrate Rust do not have to. But they also cannot dictate the language or manner of code that touches their area of control but does not alter it. The pull request Hellwig objected to "DID NOT TOUCH THE DMA LAYER AT ALL," Torvalds writes (all-caps emphasis his), and was "literally just another user of it, in a completely separate subdirectory."

"Honestly, what you have been doing is basically saying 'as a DMA maintainer I control what the DMA code is used for.' And that is not how *any* of this works," Torvalds writes.

Torvalds writes Hellwig that "I respect you technically, and I like working with you," and that he likes when Hellwig "call[s] me out on my bullshit," as there "needs to be people who just stand up to me and tell me I'm full of shit." But, Torvalds writes, "Now I'm calling you out on *YOURS*."

The leader goes on to state that maintainers who want to be involved in Rust can be, and can influence what Rust bindings look like. Those who "are taking the 'I don't want to deal with Rust' option," Torvalds writes, can do so—later describing it as a "wall of protection"—but also have no say on Rust code that builds on their C interfaces.

"Put another way: the 'nobody is forced to deal with Rust' does not imply 'everybody is allowed to veto any Rust code.'" Maintainers might also find space in the middle, being aware of Rust bindings and working with Rust developers, but not actively involved, Torvalds writes.

“Why wouldn’t we do this?”

In an earlier response to the "Rust kernel policy" topic, Kroah-Hartman suggests that, "As someone who has seen almost EVERY kernel bugfix and security issue for the past 15+ years … I think I can speak on this topic."

As the majority of bugs are due to "stupid little corner cases in C that are totally gone in Rust," Koah-Hartman is "wanting to see Rust get into the kernel," so focus can shift to more important bugs. While there are "30 million lines of C code that isn't going anywhere any year soon," new code and drivers written in Rust are "a win for all of us, why wouldn't we do this?" After casting doubt on C++ as a viable long-term codebase, Kroah-Hartman clarifies the obvious point that Rust, while not a "silver bullet," does a lot of things right, especially for developers trying to deal with the kernel's tricky APIs.

"Yes, mixed language codebases are rough, and hard to maintain, but we are kernel developers dammit, we've been maintaining and strengthening Linux for longer than anyone ever thought was going to be possible," Kroah-Hartman writes. "We've turned our development model into a well-oiled engineering marvel creating something that no one else has ever been able to accomplish. Adding another language really shouldn't be a problem, we've handled much worse things in the past and we shouldn't give up now on wanting to ensure that our project succeeds for the next 20+ years."

Rust may or may not become an ascendant language in the kernel. But maintaining C as the dominant language, to the point of actively tamping down even non-direct interaction with any C code, did not seem like a viable long-term strategy. Many discussions on the topic have noted the existence of Redox, a Rust-centered microkernel, or the theoretical but technically possible forking of Linux into a C-only project. But they are both just a smidge dismissive of how important the active development of Linux, the dominant infrastructure OS, is to the world.

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You might suspect that a one-line bill about Bigfoot that bears the number "666" is a joke, but AB-666 is apparently a serious offering from California Assemblymember Chris Rogers. Rogers represents a California district known for its Bigfoot sightings (or "sightings," depending on your persuasion—many of these have been faked), and he wants to make Bigfoot the "official cryptid" of the state.

His bill notes that California already has many official symbols, including the golden poppy (official flower), the California redwood (official tree), the word "Eureka" (official motto), the red-legged frog (official amphibian), the grizzly bear (official animal), swing dancing (official dance), and the saber-toothed cat (official fossil). The state has so many of these that there are separate categories for freshwater fish (golden trout) and marine fish (garibaldi). So why not, Rogers wants to know, "designate Bigfoot as the official state cryptid"?

That's... pretty much the bill, which was introduced this week and already has Bigfoot advocates excited. SFGate talked to Matt Moneymaker, who it describes as "a longtime Bigfoot researcher and former star of the Animal Planet series Finding Bigfoot," about the bill. Moneymaker loves it, noting that he has personally “had a face-to-face encounter one time, after which I was absolutely sure they existed because I had one about 20 feet in front of me, growling at me.”

Rogers represents California Assembly District 2, a sprawling expanse of Northern California that includes the town of Willow Grove, epicenter of the early Bigfoot sightings back in the 1950s. Today, the small community boasts the Bigfoot Museum, the Bigfoot Motel, and the Bigfoot Steakhouse—to say nothing of Bigfoot's Barbershop, Bigfoot Equipment & Repair, and, of course, the Bigfoot Cannabis Company. The bill seems like an easy way to goose interest in Bigfoot and to reap the tourist dollars that come from that interest.

This is not to deny the underlying reality of a Bigfoot-like creature (though you can indeed count me among the extremely, extremely skeptical—surely most of these sightings are of bears). Moneymaker runs the Bigfoot Field Researchers' Organization, which tracks sightings across the US. The most recent one I could find on the site was report 77,879 (!), which came from rural Buchanan County, Virginia, on November 10, 2024.

A woman working in the food service of a local prison submitted a report describing how she drove to work at 2 am for an early morning shift—and saw an alleged Bigfoot beside the road.

"I was turning on a side road at the main gate of the coal mines," she writes. "I drove less than a quarter mile from the coal mines when I saw a large what I thought was a bear or feral cow beside the road so I slowed down in case it spooked and ran across the road. That was when I noticed it was on two legs and was large but was kneeling down if I had to guess I would say it was 500–600 pounds. This animal had shaggy fur that I could see the outline of from the lights. It looked over what seemed to be its shoulder and had a human like face with a heavy brow. It looked back through the brush and then looked quickly back again before stepping toward the creek and climbed down and went out of sight. The thing that made me stop in the road was it had a knee and was looking through the brush holding it apart to look through. This "animal" had no eye shine. Once I passed its location I saw that it had been looking at 2 does."

Remarkably, this huge creature is reliably spotted alive across the US, from Virginia to a famed spot in Ohio to Willow Grove, California. Despite the ubiquity of cell phones, people keep running into Bigfeet (Bigfoots?) but can't manage to snap a compelling picture or video.

And no dead bodies are ever found. And when scientists do put out calls for possible Bigfoot hair, what they get is material from horses, bears, tapirs, cows, raccoons, and mule deer—but nothing from a Bigfoot. And let's not even get started on attempts to sequence the DNA of a Bigfoot.

Clearly, if it exists, this is one crafty animal. And it might just become California's next official symbol.

Or it might not. A similar idea was proposed in Washington state in 2017. Despite being reintroduced several times, the bill never seems to have made it out of committee.

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Garbage truck fires are never ideal, but they are usually not catastrophic. When a fire broke out on December 6 in the back of a garbage truck making its Friday rounds through the Chicago suburb of Arlington Heights, the fire department responded within five minutes. Firefighters saw flames shooting five feet into the air out the back of the truck, and they prepared to put the fire out using hoses and water. Four minutes after their arrival on scene, however, the garbage truck exploded in rather spectacular fashion, injuring several firefighters and police officers, damaging several homes in the vicinity, and scattering debris through the neighborhood.

The truck, it turned out, was powered by compressed natural gas (CNG), stored in five carbon-fiber-wrapped cylinders on the roof. The cylinders had pressure relief valves installed that should have opened when they reached a temperature between 212° and 220° Fahrenheit (100°–140° Celsius). This would vent (flammable) methane gas into the atmosphere, often creating a powerful flamethrower but keeping the tanks from exploding under the rising pressure caused by the heat. In this case, however, all the pressure relief devices failed—and the CNG tanks exploded.

Fire officials now believe that the whole incident began when a resident improperly disposed of a lithium-ion battery by placing it in a recycling bin.

Explosion on a sunny day

December 6, 2024, was a sunny day with temps in the mid-30s when local dispatch received a call from the driver of a garbage truck operated by a local company called Groot. The driver said that his load was on fire. Arlington Heights firefighters had dealt with six garbage truck fires in the last several years and had no reason to believe that this call would be exceptional.

Typically, a garbage truck driver will compress the truck's load if fire is seen, starving the flames of oxygen and often putting the fire out. The driver of the burning truck had tried this, but the maneuver failed. Apparently, some of the flammable material got under the slide bar of the compactor, spreading the fire further into the truck.

When firefighters arrived on scene, they asked the driver to dump his load in the street, which would reduce the risk of anything on the truck itself—gasoline, CNG, etc.—catching fire. Then the firefighters could put out the blaze easily, treating it like a normal trash fire, and have Groot haul away the debris afterward. But this didn't work either. The flames had spread far enough by this point to put the truck's dumping mechanism out of commission.

So, firefighters unrolled hoses and hooked up to a nearby fire hydrant. They recognized that the truck was CNG-powered, as were many Groot vehicles. CNG offers a lower maintenance cost, uses less fuel, and creates less pollution than diesel, but best practices currently suggest not spraying CNG cylinders directly with water. Firefighters instead tried to aim water right into the back of the garbage truck without wetting the CNG cylinders nearby on the roof.

They were waiting for the telltale hiss of the pressure relief system to trigger. These valves typically open within two to five minutes, depending on fire conditions, and they should be capable of venting all their natural gas some minutes before the CNG canisters would otherwise be in danger of exploding. But the hiss never came, and as Fire Chief Lance Harris and his crew worked to secure the scene and put water onto the burning load, the CNG canisters exploded catastrophically instead.

In a board of trustees meeting this week in Arlington Heights, Harris recounted the incident, noting that he felt lucky to be alive—and thankful that no township personnel or residents sustained serious injuries.

"We can't prove it," he said, but after two months of investigating the situation, his department had concluded with high probability that the fire had been caused by a lithium-ion battery discarded into a recycling container. This suspicion was based on the amount of fire and the heat and speed with which it burned; lithium-ion batteries that enter "thermal runaway" can burn hot, at around 750° Fahrenheit (399° C).

Harris' takeaway was clear: recycle even small lithium-ion batteries responsibly, as they can cause real hazards if placed into the waste system, where they are often impacted or compressed.

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In a remarkable statement Thursday, SpaceX founder Elon Musk said the International Space Station should be deorbited "as soon as possible."

This comment from Musk will surely set off a landmine in the global space community, with broad implications. And it appears to be no idle comment from Musk who, at times, indulges in deliberately provocative posts on the social media network X that he owns.

However, that does not seem to be the case here.

"It is time to begin preparations for deorbiting the @Space_Station. It has served its purpose. There is very little incremental utility. Let’s go to Mars," Musk wrote at midday on Thursday.

This original statement was somewhat ambiguous. Last July, NASA awarded Space X an $843 million contract to modify a Dragon spacecraft to serve as a propulsive vehicle to safely guide the aging space station into the Pacific Ocean in 2030. So in some sense, preparations are already underway to shut down the laboratory.

I asked Musk if he meant that NASA and the US government should commit to the 2030 end-of-life date, or if he wanted to accelerate the timeline for the station's demise.

"The decision is up to the President, but my recommendation is as soon as possible. I recommend 2 years from now," Musk replied.

In other words, the owner of SpaceX, the most powerful actor in spaceflight globally, and one of the most powerful people in the world who is presently working alongside the US president to transform the government, wants to bring the space station down in early 2027.

Myriad ramifications

The politics of this are complicated. President Trump could propose shutting down the space station, but the budget for the deorbit vehicle (which is necessary, otherwise the station might make an uncontrolled reentry over land) must be funded by Congress.

The space station has key supporters in Congress, including Sen. Ted Cruz (R-Texas), in whose state the orbiting laboratory is managed. Cruz has long been an advocate of the space station. Ars reached out to Cruz for a comment on Thursday, but the senator did not immediately respond.

However, a key source said Cruz was "furious" with the sentiment from Musk. The timing of Musk's tweet could make the confirmation of private astronaut Jared Isaacman to become NASA administrator more difficult. As part of the confirmation process, Isaacman is due to begin meetings with US senators in the coming week.

Having to answer questions about the end-of-life for the space station will make some of these meetings uncomfortable.

As chairman of the US Senate Committee on Commerce, Science, & Transportation, Cruz effectively has control over Isaacman's confirmation process. He was also just re-elected to a six-year term, so theoretically Cruz is less susceptible to political pressure from the Trump White House.

NASA in a tight spot

Musk's statement would also put NASA in a difficult position. The US space agency, along with most of the international partners, wants to keep the space station operating until at least 2030. Roscosmos, Russia's space agency, has formally committed to operating the space station through at least 2028. The United States and Russia each operate a large segment of the space station, and cooperation from both major partners is necessary to keep the lab flying.

In reality, NASA has only been fully utilizing the space station since late 2020, when it began to fly a full complement of astronauts thanks to SpaceX's Crew Dragon coming online. The agency says it has a lot of worthwhile scientific and human performance research to conduct over the next five years.

NASA's selection of a deorbit vehicle last summer was a concrete signal that it intends to end the life of the venerable space station in 2030.

Some stakeholders, including Boeing, which has a large contract to operate the station for NASA, have suggested the facility could fly beyond 2030. However, structural elements of the station have been in space for more than a quarter of a century, and NASA is growing increasingly concerned about leaks in Russian modules aboard the facility.

As the ISS goes away, NASA's plan is to transition operations to private space stations in low-Earth orbit, a plan it calls "Commercial LEO Destinations." The space agency has provided some funding to four different companies to begin work on these stations.

Nevertheless, this program is generally underfunded, and there are questions about the viability of private companies operating facilities in space by or before 2030. The general consensus in the space community is that if NASA wants to have even a single private space station operating in low-Earth orbit by 2030, it will need to increase funding for this.

What is Elon doing?

There are some plausible explanations for why Musk would seek to end the life of the space station early. His statement about "Let's go to Mars" implies that the money presently being spent on the space station should be repurposed toward human exploration of Mars.

NASA's annual budget for the International Space Station is a little more than $3 billion. Of this more than half is spent on "transportation," which is cargo and crew supply missions. In 2023, for example, NASA spent $1.76 billion on transportation to the station, the majority of which went to SpaceX for its Dragon cargo and crew flights.

Canceling NASA's operations in low-Earth orbit could free up some funding for Mars if Cruz and the other ISS supporters in Congress agree, which seems questionable.

Musk has likely told Trump that NASA does not need to fund private space stations in low-Earth orbit. Rather, Musk could offer an alternative solution if NASA wants to maintain a presence there. SpaceX already plans to launch multiple Starship vehicles into space, and NASA is working on Starship life support systems for its Artemis missions. A version of Starship could be developed to provide a semi-permanent presence in low-Earth orbit.

This is, of course, easier said than done.

It would also wreck the business plans of multiple US companies working to provide this capability for NASA. Moreover, it would shoulder even more responsibility for the US space enterprise onto a single company, SpaceX. This goes against NASA's long-standing policy to have multiple providers and its desire to foster a healthy ecosystem of commercial space companies.

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An asteroid discovered late last year is continuing to stir public interest as its odds of striking planet Earth less than eight years from now continue to increase.

Two weeks ago, when Ars first wrote about the asteroid, designated 2024 YR4, NASA's Center for Near Earth Object Studies estimated a 1.9 percent chance of an impact with Earth in 2032. NASA's most recent estimate has the likelihood of a strike increasing to 3.2 percent. Now that's not particularly high, but it's also not zero.

Naturally the prospect of a large ball of rock tens of meters across striking the planet is a little worrisome. This is large enough to cause localized devastation near its impact site, likely on the order of the Tunguska event of 1908, which leveled some 500 square miles (1,287 square kilometers) of forest in remote Siberia.

To understand why the odds from NASA are changing, and whether we should be concerned about 2024 YR4, Ars connected with Robin George Andrews, author of the recently published book How to Kill an Asteroid. Good timing with the publication date, eh?

Ars: Why are the impact odds increasing?

Robin George Andrews: The asteroid’s orbit is not known to a great deal of precision right now, as we only have a limited number of telescopic observations of it. However, even as the rock zips farther away from Earth, certain telescopes are still managing to spy it and extend our knowledge of the asteroid’s orbital arc around the Sun. The odds have fluctuated in both directions over the last few weeks, but overall, they have risen; that’s because the amount of uncertainty astronomers have as to its true orbit has shrunk, but Earth has yet to completely fall out of that zone of uncertainty. As a proportion of the remaining uncertainty, Earth is taking up more space, so for now, its odds are rising.

Think of it like a beam of light coming out of the front of that asteroid. That beam of light shrinks as we get to know its orbit better, but if Earth is yet to fall out of that beam, it takes up proportionally more space. So, for a while, the asteroid’s impact odds rise. It’s very likely that, with sufficient observations, Earth will fall out of that shrinking beam of light eventually, and the impact odds will suddenly fall to zero. The alternative, of course, is that they'll rise close to 100 percent.

Ars: What are we learning about the asteroid's destructive potential?

Andrews: The damage it could cause would be localized to a roughly city-sized area, so if it hits the middle of the ocean or a vast desert, nothing would happen. But it could trash a city, or completely destroy much of one, with a direct hit.

The key factor here (if you had to pick one) is the asteroid’s mass. Each time the asteroid gets twice as long (presuming it’s roughly spherical), it brings with it 8 times more kinetic energy. So if the asteroid is on the smaller end of the estimated size range—40 meters—then it will be as if a small nuclear bomb exploded in the sky. At that size, unless it’s very iron-rich, it wouldn’t survive its atmospheric plunge, so it would explode in mid-air. There would be modest-to-severe structural damage right below the blast, and minor to moderate structural damage over tens of miles. A 90-meter asteroid would, whether it makes it to the ground or not, be more than 10x more energetic; a large nuclear weapon blast, then. A large city would be severely damaged, and the area below the blast would be annihilated.

Ars: Do we have any idea where the asteroid might strike on Earth?

Andrews: The "risk corridor" is currently spread over parts of the eastern Pacific Ocean, northern South America, the Atlantic Ocean, parts of Africa, the Arabian Sea and South Asia. Additional observations will ultimately narrow this down, if an impact remains possible.

Ars: What key observations are we still waiting for that might clarify the threat?

Andrews: Most telescopes will lose sight of this "small" asteroid in the coming weeks. But the James Webb Space Telescope will be able to track it until May. For the first time, it’s been authorized for planetary defense purposes, largely because its infrared eye allows it to track the asteroid further out than optical light telescopes. JWST will not only improve our understanding of its orbit, but also constrain its size. First observations should appear by the end of March.

JWST may rule out an impact in 2032. But there's a chance we may be stuck with a few-percentage impact probability until 2028, when the asteroid makes its next Earth flyby. Bit awkward, if so.

Ars: NASA's DART mission successfully shifted an asteroid's orbit in 2022. Could this technology be used?

Andrews: Not necessarily. DART—a type of spacecraft called a kinetic impactor—was a great success. But it still only changed Dimorphos' orbit by a small amount. Ideally, you want many years of advance notice to deflect an asteroid with something like DART to ensure the asteroid has moved out of Earth’s way. I've often been told that at least 10 years prior to impact is best if you want to be sure to deflect a city killing-size asteroid. That’s not to say deflection is impossible; it just becomes trickier to pull off. You can’t just hit it with a colossal spacecraft, because you may fragment it into several still-dangerously sized pieces. Hit it too softly, and it will still hit Earth, but somewhere that wasn’t originally going to be hit. You have to be super careful here.

Some rather clever scientists at the Lawrence Livermore National Laboratory (which has a superb planetary defense contingent) worked out that, for a 90-meter asteroid, you need 10 years to confidently deflect it with a kinetic impactor to prevent an Earth impact. So, to deflect 2024 YR4, if it’s 90 meters long and we have just a few years of time, we’d probably need a bigger impactor spacecraft (but don’t break it!)—or we’d need several kinetic impactors to deflect it (but each has to work perfectly).

Eight years until impact is a little tight. It’s not impossible that the choice would be made to use a nuclear weapon to deflect it; this could be very awkward geopolitically, but a nuke would impart a bigger deflection than an equivalent DART-like spacecraft. Or, maybe, they’d opt to try and vaporize the asteroid with something like a 1 megaton nuke, which LLNL says would work with an asteroid this size.

Ars: So it's kind of late in the game to be planning an impact mission?

Andrews: This isn’t an ideal situation. And humanity has never tried to stop an asteroid impact for real. I imagine that if 2024 YR4 does become an agreed-upon emergency, the DART team (JHUAPL + NASA, mostly) would join forces with SpaceX (and other space agencies, particularly ESA but probably others) to quickly build the right mass kinetic impactor (or impactors) and get ready for a deflection attempt close to 2028, when the asteroid makes its next Earth flyby. But yeah, eight years is not too much time.

A deflection could work! But it won’t be as simple as just hitting the asteroid really hard in 2028.

Ars: How important is NASA to planetary defense?

Andrews: Planetary defense is an international security concern. But right now, NASA (and America, by extension) is the vanguard. Its planetary defenders are the watchers on the wall, the people most responsible for not just finding these potentially hazardous asteroids before they find us, but also those most capable of developing and deploying tech to prevent any impacts. America is the only nation with (for now!) a well-funded near-Earth object hunting program, and is the only nation to have tested out a planetary defense technique. It’s a movie cliché that America is the only nation capable of saving the world from cosmic threats. But, for the time being—even with amazing planetary defense mission contributions from ESA and JAXA—that cliché remains absolutely true.

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