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Earth's inner core isn't just slowing, it's also shape-shifting, study finds

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Earth's inner core isn't just slowing, it's also shape-shifting, study finds

USC scientists have made a groundbreaking discovery about the nature of the Earth’s enigmatic inner core, revealing for the first time that this 1,500-mile-wide ball of iron and nickel is changing.

The planet’s inner core was previously thought of as a hard, solid sphere. But a new study has found that its edges are softer than realized and actually changing shape as they press against the liquid iron and nickel in Earth’s outer core.

“The molten outer core is widely known to be turbulent, but its turbulence had not been observed to disrupt its neighbor the inner core on a human timescale,” said USC Earth Sciences professor John Vidale, who led the study. “What we’re observing in this study for the first time is likely the outer core disturbing the inner core.”

Vidale said it’s likely the outer core is deforming the shape of the inner core, pushing it a kilometer or two in areas where they rub together with force. These findings were published Monday in a study conducted alongside researchers from the University of Chinese Academy of Sciences, Cornell University and the University of Utah.

When his team members embarked on their research, they did not expect to document structural changes to the Earth’s inner core. Instead,they were focused on learning more about the slowing of its rotation.

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Previous research has found that the rotation of the inner core is slowing down relative to the rotation of the external crust, which may cause minute changes in Earth’s rotation and subtly affect the length of a day. Although these time changes are only estimated to be a matter of milliseconds a year, they can accumulate over eons.

Vidale said he was busy studying graphs that record ground vibrations caused by seismic waves when one data set “curiously stood out from the rest.”

“Later on, I’d realize I was staring at evidence the inner core is not solid,” he added.

His team was studying seismic data from 121 repeating earthquakes at 42 locations near Antarctica’s South Sandwich Islands that occurred between 1991 and 2024.

Repeating earthquakes are quakes with the same magnitude and location. If a pair of repeating earthquakes happen while the Earth’s inner core is at the same location in its rotation, scientists would assume that the seismic data recorded would be the same in both earthquakes.

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However, the curious data set that Vidale came across defied this logic, prompting his team to realize that the differences they observed were likely caused by changes in the shape of the inner core.

“We see these subtle differences,” he said. “And if they’re not [caused by] the inner core turning, the most likely possibility is there’s some deformation in the soft outermost inner core.”

The scientific implications of this revelation are not yet clear, but Vidale hopes it can help researchers untangle further mysteries related to the inner core and lead to better understanding of Earth’s thermal and magnetic fields.

“We hope it has broader implications,” he said. “The reason we do this is we like to solve riddles, and the stranger and harder the riddle that we can solve, the happier we are.”

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Video: NASA Announces Artemis III Crew

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Video: NASA Announces Artemis III Crew

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NASA Announces Artemis III Crew

NASA announced the crew of Artemis III mission, which will fly to low-Earth orbit to test rendezvous and docking maneuvers with one or two lunar landers.

“I am excited to welcome you as the next crew in the Artemis journey to successfully return to the moon — this time to stay.” “I’m honored by the role that I’ve been given. I’m also very humbled by the task in front of us. But first and foremost, I’m grateful.” “So with that, the Artemis II crew, comrade, hands you the baton. You got the controls.” “As you know, we had a significant anomaly at our Launch Complex 36A on May 28. We’ve redoubled our efforts and are moving forward.”

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NASA announced the crew of Artemis III mission, which will fly to low-Earth orbit to test rendezvous and docking maneuvers with one or two lunar landers.

By Alisa Shodiyev Kaff

June 9, 2026

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Santa Monica Mountains’ last steelhead trout survived the Palisades fire — and even had babies

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Santa Monica Mountains’ last steelhead trout survived the Palisades fire — and even had babies

Scientists feared the Santa Monica Mountains’ last remaining steelhead trout were dead, smothered by debris flows unleashed by the Palisades fire.

But the endangered fish surprised them: A team of biologists recently spotted 30 of the rare trout — and 21 babies — in Topanga Creek.

“There was a lot of happy dancing in the creek,” said Rosi Dagit, principal conservation biologist for the Resource Conservation District of the Santa Monica Mountains, which works with public and private landowners to conserve natural resources.

That’s because the steelhead here are endangered, at both the state and federal levels. Once, they swam in most streams of the Santa Monicas, but their numbers plummeted amid overfishing and coastal development. Increasingly frequent wildfire has further stressed their habitat. Topanga Creek, a biodiversity hot spot, is home to their last known population in the mountains that stretch from the Hollywood Hills to Point Mugu in Ventura County.

The trout that were spotted, including this one, are part of a distinct Southern California population that’s listed as endangered at the state and federal levels.

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(RCDSMM Stream Team)

The California Department of Fish and Wildlife spearheaded a complex mission to rescue trout threatened by the Palisades fire that sparked in January 2025.

Time was of the essence. The fire hadn’t yet been fully contained. But rain was on the way, which would sweep massive amounts of sediment from the denuded hillsides into the water. Fish are often killed this way.

Crews stunned the fish with electricity, scooped them up in buckets, trucked them to a hatchery and ultimately moved them to Arroyo Hondo Creek in Santa Barbara County.

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Within days, Topanga Creek was choked with mud. Some assumed the fish left behind were goners.

But in March, the conservation district’s team found four. The following month, when water conditions were clearer, they saw more.

“These fish continue to amaze me,” said Kyle Evans, environmental program manager for the state Department of Fish and Wildlife, who had seen the damage to the creek. “I had seen populations get wiped out in similar situations. So when I heard, I was thrilled.”

Evans surmises the fish that survived were in an area of the creek where less charred material and sediment were swept in.

“These fish likely hunkered down, were hiding under some rocks or places to try to get away from the main concentration of flow,” he said. “And luckily they weren’t buried.”

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The ones that were spotted were fairly small, around 6 to 14 inches. Rainbow trout and steelhead trout are the same species, but with different lifestyles. If the fish remain in freshwater, they’ll be considered rainbows. However, they can migrate to the ocean and become steelhead, where they typically grow larger before returning to their natal waters to spawn.

Topanga Creek hasn’t fully recovered from the damage it sustained, but scientists say it’s looking better. Surveys last year were “so depressing,” Dagit said, with very few animals, and stretches that were essentially transformed into flat roads from all the sediment buildup. Some of the riparian canopy burned right down to the creek.

Then came 32 inches of rain over the last nine months, scouring out and moving sediment, creating deeper pools. Dagit said they recently found newt egg masses for the first time in years, as well as a few adult newts and many frogs. Plants that provide cover are starting to recover.

She provided photos comparing certain pools last year and this year, some dramatically transformed. In September 2025, the Shrine Pool could have been an overgrown hiking trail. This April, it was filled with shallow water.

Shrine Pool, Sept. 2025, left, and the same location, April 2026, right.

The Shrine Pool in September 2025, left, and the same location in April 2026, right, with RCDSMM’s Isaac Yelchin donning a wetsuit.

(RCDSMM Stream Team)

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Topanga Creek is home to another endangered fish, the small but hardy northern tidewater goby, often described as cute. Not long before the trout operation, Dagit led a rescue of hundreds of these fish too. Many were repatriated to the lagoon at the mouth of the creek in a moving ceremony last June.

There’s still the matter of what to do with the trout that were moved to Santa Barbara County last year. Evans would like to bring them home to the Santa Monicas at some point, but isn’t sure if it will happen. On one hand, they could bolster the small, genetically isolated surviving population. On the other, they might inadvertently bring in a disease or bacteria. There is some time to decide. Evans estimates the creek still needs to recover for two to three more years.

For now, the fish are functioning fine in their adopted creek. Experts worried the trauma wrought by the move would disrupt their spawning process, but they had babies that spring. This year, they spawned again.

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Pacifica pier cracks, another coastal casualty as seas continue to rise

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Pacifica pier cracks, another coastal casualty as seas continue to rise

The Pacifica Municipal Pier was shut down and taped off Thursday after city workers noticed cracks running through the landmark structure and concrete chunks falling into the ocean.

It’s just one of many coastal California structures that have recently crumbled under pressure from a rising and relentless ocean.

Officials from the small, beach city south of San Francisco said the pier was closed due to “cracking, separation, and displacement of the concrete walkway and structural elements.”

It will stay closed while structural engineers asses its safety.

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Photos taken by city employees show a wide crack that runs from top to bottom and across the structure as well. Other photos show a large horizontal crack under the foundation of a small restaurant on the pier, the Chit Chat Cafe.

The cafe was also shut down.

This is not the first time the 53-year-old pier has shown signs of stress. In 2021, part of it was shut down after handrails along the edge collapsed. And in 2023, after a series of storms pummeled the Central California coast, damaging parts of the pier, the structure was partially closed for more than year.

Those same storms caused extensive damage in Aptos and Capitola, 70 miles south, where piers and waterfront infrastructure were swept away or damaged.

In 2024, a 150- to 180- foot section of the Santa Cruz wharf was ripped off by powerful waves.

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At least 10 of the state’s dozens of coastal public piers were closed for part or all of 2024 due to structural damage sustained in winter storms since 2022. At least five others have longer-term upgrades planned to address structural issues.

“These things are costly to maintain,” said Zach Plopper, senior environmental director at Surfrider. “They are a part of our California coastal culture in many ways, but we’re going to need to reckon with, one, the state that they’re in, and two, the continuous and worsening threats they’re going to experience,”

He said most of the piers were constructed in the early 1900s, and they weren’t built to withstand decades of rough seas, storms and rising sea level.

“With this incoming El Niño, which is forecasted to be significant, and this marine heat wave we’re in the midst of, we’re kind of in uncharted waters as far as what this winter could bring in terms of storms and swells to the California coast, and we’re likely going to see a lot more damage,” he said. “Not just piers, but roads and other coastal infrastructure up and down the state.”

There was no storm in Pacifica earlier this week, so no single event could be blamed for the destruction.

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However, a 2025 report from an outside engineering firm, GHD, found that several sections of the pier were in “poor” or “serious” condition, and they recommended closure before anticipated storms or events that could “subject the piles to high winds, swells and large waves.”

The firm found several areas of the pier where concrete was missing and rebar was exposed and corroding.

“The pier has continued to experience high winds and large waves in a harsh marine environment,” the engineers wrote in the report, noting that continuous exposure to seawater or marine spray was “detrimental” to the structure.

A 2023 city report estimated it would cost $19 million to repair.

That same year, a state law was enacted to require local governments along the California coast to plan for sea level rise in the coming decades.

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Sea level has risen some 8 inches, on average, along the coast in the past 150 years, Plopper said, and researchers anticipate another foot in the next 25 years.

“We’re going to see profound shifts on our coastline, none that we have ever experienced before, and building static structures on the coast just doesn’t work all that well,” he said. “We’re going to have to make some really hard decisions.”

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