Physicist Ronald Koopman appeared at a Southern California Air District meeting in 2018 to talk about what seemed like an arcane scientific topic: hydrofluoric acid dispersion and water mitigation testing.

Hydrofluoric acid, also known as hydrogen fluoride or HF, is used to manufacture a range of materials, including refrigerants, gasoline, fluorine-based pesticides and fluoropolymers like those used to make Teflon. It’s also one of the most corrosive and dangerous chemicals known. Koopman conducted experiments with the chemical in the 1980s that warned about the potential of deadly accidents at facilities that use the hazardous materials.

With the Trump administration poised to roll back rules intended to protect workers and communities from catastrophic industrial chemical releases, and a new analysis showing rising rates of chemical accidents, Koopman’s presentation on highly hazardous materials has taken on a new urgency.

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Earth is the only planet we know of with buoyant, silica-rich continents. But, despite decades of research, geologists still don't agree on how they formed. "The continents started appearing around about four billion years ago—that's the oldest continental rock we know about,” said Tim Johnson, a geologist at Curtin University in Perth, Australia. “The Earth is four and a half billion years old, so why they started appearing then is unknown, as is the mechanism to make that continental crust."

Johnson and his colleagues are now arguing that the formation of continents on Earth was caused largely by an intense, sustained barrage of asteroid impacts that kept the early crust hot and thin enough to make buoyant continents possible. In short, the lands we live on are here because of ancient bombardment from space.

Plates and plumes

The problem with studying the formation of continents is that the geological evidence of this process is almost gone. The oldest known continental-type rocks crystallized around 4.03 billion years ago, right at the end of the Hadean eon (the earliest era in Earth’s history, spanning the first 500 million years of its existence). Rare basaltic rocks date back about 4.2 billion years, and a handful of the oldest zircon crystals push the record back to 4.4 billion years. Beyond that, there's hardly anything else. So, scientists looking into the origin of continents had to rely largely on educated guesses. “There are huge debates about what was going on in the early Earth, because the data is so scarce,” Johnson said.

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Pour one out for Supergirl , the latest installment in the DCU's Gods and Monsters chapter, which has been beset by online troll attacks, mixed reviews, and a very disappointing opening weekend box office—not the outcome Warner Bros. was hoping for with this follow-up to last year's Superman . It's actually a pretty good movie, as such films go, but it's not a great movie. And in today's over-saturated superhero market, that's just not sufficient to get people out of their homes and into theaters, rather than waiting for the film to come to streaming platforms.

(Some spoilers below but no major reveals.)

The studio tapped Ana Nogueira to write the script, a holdover from the former DCEU plans for a standalone Supergirl film. (The character appeared in the finale of 2022's The Flash , played by Sasha Calle.) The project was reimagined when James Gunn and Peter Safran took over and launched the "soft reboot" DCU. Director Craig Gillespie ( Lars and the Real Girl, I Tonya ) signed on to direct.

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About 14 years ago, Chrissi Kelly lost her sense of smell. She had traveled to the Czech Republic to visit family and caught some virus. Months later, when she still couldn’t smell, she made the rounds to doctors, including her general practitioner and an ear, nose and throat specialist, trying to find answers.

She was diagnosed with anosmia (smell loss), and like many patients with her condition, was told she’d have to learn to live with it. But for her, the loss was catastrophic. “After about six months of complete loss, I was just climbing the walls, and I did not feel like myself anymore,” she says.

Researchers estimate that up to 22 percent of the population lives with smell impairments , like hyposmia (partial smell loss) or anosmia (complete smell loss). And many others live with smell disorders like phantosmia, in which a person picks up phantom smells, or parosmia, where typically pleasant scents like coffee or shampoo begin to register as highly unpleasant (think feces or vomit). Yet the conditions have been poorly understood, underdiagnosed and often minimized by clinicians.

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NASA’s Perseverance rover has spent five years traversing Jezero Crater looking for the chemical leftovers of whatever processes were at work on Mars billions of years ago. The rover has found organic carbon, but it has mostly been inside rocks that had to be drilled or abraded to expose it. But now, at an outcrop on the edge of an ancient river channel named Neretva Vallis, Perseverance detected complex macromolecular carbon sitting right on the rock’s surface.

“To our knowledge, that’s the shallowest detection of organic matter on Martian surface to date,” said Ashley E. Murphy, a researcher at the Planetary Institute in Tucson, Arizona, and lead author of the study of the rock, which was found at a site called Bright Angel. On Earth, this much macromolecular carbon usually suggests a biological origin. But to learn what this Bright Angel carbon is and where it came from, we might need to bring samples back to Earth.

Carbon on the rocks

The detection of Bright Angel carbon came from SHERLOC (Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals), a UV Raman spectrometer fitted on Perseverance’s robotic arm. SHERLOC fires a deep-ultraviolet laser at a target and reads the light that bounces back at shifted energies, a signal that enables scientists to identify specific molecular bonds.

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Researchers have found a never-before-seen piece of macOS malware that combines a series of clever tradecraft to infect Macs with stealthy, custom-developed credential-stealing code.

The malware is delivered in two stages. The first is distributed in a disk image that masquerades as Maccy , a clipboard manager for Macs. It’s compiled as AppleScript that is notable for the way it delivers the second stage. The malware is named PamStealer because the Rust-written infostealer uses the Pluggable Authentication Modules interface built into macOS to validate the target’s login password before sending it to an attacker-controlled server.

A quieter execution chain

The use of both disk image and AppleScript is common in malware for Macs. More unusual is the way PamStealer combines them to gain stealth. When the AppleScript is double-clicked, it’s opened in the macOS Script Editor, where the malicious functionality is buried deep within the file.

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A long-standing ban on commercial supersonic flights over the United States would be overturned in a new rule proposed by the US Federal Aviation Administration. That could pave the way for the possible return of commercial supersonic airliners—as long as such aircraft can reduce the ground-level impacts of their sonic booms.

The FAA originally banned overland supersonic flights by civil aircraft in 1973, following US military tests involving supersonic flights over US cities such as Oklahoma City, Chicago, and St. Louis in the 1960s. But the Trump administration has championed the repeal of the ban to pave the way for supersonic airliners that could operate without disruptive sonic booms. So the FAA’s new rulemaking action on June 30, 2026, follows the direction of an executive order issued by President Trump on June 6, 2025.

The newly proposed rule would replace the 53-year prohibition with an interim “noise-based” certification standard requiring any sonic boom overpressure at the surface to be kept below 0.11 pounds per square foot. That proposed standard is based on the Colorado-based startup Boom Supersonic having demonstrated quiet Mach cutoff flights with its XB-1 aircraft —harnessing specific atmospheric conditions while flying just beyond supersonic speeds at higher altitudes so that the aircraft’s shockwaves are refracted upward into the atmosphere rather than traveling to the ground.

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This week Ars hosted a live discussion with two space industry experts about the aftermath of the catastrophic explosion of the New Glenn rocket in late May.

Along with Ars Technica Space Editor Eric Berger; the director of research at Quilty Space , Caleb Henry; and the host of the Main Engine Cut Off podcast , Anthony Colangelo, spoke about various topics. Chief among them was the implications of this failure for NASA's attempt to land humans on the Moon for the Artemis IV mission. Blue Origin and SpaceX are both building landers to support this goal and the rockets to deliver them to the Moon.

During the conversation, Berger reported that the current Blue Origin "architecture" for a human mission would require four launches of new variant of the New Glenn rocket, known as 9x4, because it has nine first stage engines, and four upper stage engines. This is a more powerful version than the "7x2" variant that exploded a little more than a month ago. Blue Origin has not set a target date for the 9x4 rocket's debut, but some sources have indicated the company is targeting late 2027 or early 2028.

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When Plex launched in 2012, it sold lifetime access to its media server software for $75. In 2014, Plex raised the price to be more sustainable for the company, it said, and for years, Lifetime Plex Passes cost $120. Even the pricier $250 rate, which Plex offered from March 2025 until yesterday, was a steal compared to what $250 buys you at Plex now: a five-year subscription.

As first spotted by The Desk , Plex yesterday launched the five-year Plex Pass. It comes alongside Lifetime Pass prices increasing to $750 yesterday, a change that Plex announced in May and, in a blog post update this week, said: “reflects the real, ongoing value of the software and our commitment to building, improving, and supporting Plex for years to come.”

The stark change in what $250 can get you at Plex is indicative of the company’s financial goals. Plex hasn’t yet announced profitability and has raised $87.6 million over nine rounds of funding, per CB Insights . The company is looking to squeeze more money out of its users and price its media server business higher.

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