The range is almost absurd. Engineers built the decibel scale logarithmically because the linear numbers were unusable.

What “threshold of hearing” actually means

The reference point — 0 dB SPL — is not silence. It is the quietest 1,000-hertz tone a young adult with unimpaired hearing can just barely detect in a controlled laboratory. Some people hear below it. Microsoft’s anechoic chamber in Building 87 on the Redmond campus measures a background level near -20 decibels, below the conventional threshold and close to the theoretical floor set by air molecules bumping into one another.

Inside that room, visitors report hearing their own heartbeat, their own breath, the faint click of joints in a shoulder or knee. The ordinary masking noise of the world — traffic, refrigerators, distant conversation, the hum of the room itself — is gone. What remains is the body.

The chamber sits on springs. Its foundation is separated from the rest of the building so that footsteps in the corridor cannot leak through the concrete. Sound-absorbing wedges line every surface. It was built for measuring microphones and speakers, not for testing human endurance, and the widely repeated claim that nobody lasts more than 45 minutes inside is not a documented scientific limit — it appears to be a viral misattribution from a different chamber, the one at Orfield Laboratories in Minneapolis, which held the world-quietest title before Microsoft took it.

Why the scale is logarithmic

Consider the numbers in linear form. A whisper measures about 30 dB SPL. Normal conversation, 60 dB. A vacuum cleaner, 75. A motorcycle at close range, 95. A chainsaw, 110. A jet engine at 30 metres, roughly 130. The rupture threshold of the eardrum sits around 185–190 dB SPL, a level reached only by explosions and large rocket engines.

Because the decibel scale adds 10 for every tenfold increase in power, the jump from a whisper to a jet engine is a factor of ten billion in acoustic power. The jump from the threshold of hearing to the threshold of pain, roughly 120–130 dB, is a factor of one trillion in power and about a million in pressure amplitude. The ear handles this without a switch, a fuse, or a gain knob the listener controls.

It handles it with hair cells.

The mechanical trick inside the cochlea

The cochlea is a fluid-filled spiral about the size of a pea. Running along its length is the basilar membrane, and sitting on that membrane are roughly 15,000 sensory hair cells arranged in rows. When sound enters the ear canal, the eardrum vibrates, three tiny bones in the middle ear amplify the motion, and a piston-like footplate pushes on the fluid inside the cochlea. The basilar membrane ripples. The hair cells bend. Each bend opens ion channels at the tip of the hair bundle, and a nerve signal fires.

The outer hair cells do something stranger. They actively contract and expand in time with the sound wave, pumping energy back into the basilar membrane to sharpen the response to quiet signals. At low volumes, the cochlea is essentially amplifying itself. At high volumes, that active amplification shuts down and the system runs passively, which is part of why the ear can span such a range without saturating.

This is compression built into biology. A microphone with the same dynamic range would need an engineer riding the fader.

Where the trillion-fold range breaks down

The system is not indestructible. Push it hard enough, long enough, and the hair cells that made the amplification possible begin to die. They do not grow back. Noise-induced hearing loss is almost entirely a story of these cells being worn down by exposure that the ear was never evolved to handle: engines, amplified music, industrial machinery, headphones held close.

A 2020 review in Frontiers in Neurology, led by researchers at Massachusetts Eye and Ear and Harvard Medical School, gathered the published evidence on what happens when people are exposed to acoustic energy outside the conventional hearing range — infrasound below 20 Hz, ultrasound above 20,000 Hz. The reported symptoms include dizziness, tinnitus and aural fullness. The authors were careful about how much weight the evidence bears: most of it comes from case series and small cohorts, and the underlying mechanism is not settled.

At the other end of the spectrum, a study published in Scientific Reports in January 2026 followed 42 young adults through large-scale music festivals, with personal dosimeters recording an average exposure of about 100 decibels across roughly ten hours. Only one of them showed a clinically significant drop in hearing sensitivity on a standard audiogram. But five showed reductions in electrophysiological markers of synaptic damage within 24 hours of the event, and in two of those the reduction was still measurable two weeks later, with normal hearing thresholds throughout.

That is the uncomfortable part. The trillion-fold range is real. The margin for using the top of it repeatedly is not — and the damage does not always show up on the test most people are given.

A public health problem hiding in the wonder

The World Health Organization warns that over one billion young people globally are at risk of permanent hearing loss from prolonged exposure to loud music through personal listening devices and noisy venues. In the WHO African Region, about 40 million people live with hearing loss, a prevalence of 3.6 percent, and the failure to address it is estimated to cost African economies US$27.1 billion a year. On current trends that figure reaches 54 million by 2030.

Most of that damage is preventable. The WHO notes that more than 60% of childhood hearing loss can be avoided with basic public health measures: vaccination against meningitis, treatment of ear infections, safer listening habits, and screening. In adults, the leading modifiable causes are noise exposure and ototoxic medications.

Children are especially vulnerable because their ear canals are shorter, which can amplify certain frequencies, and because damage accumulates over a lifetime. Toys, headphones and ordinary public environments — arcades, sporting events, film screenings — regularly cross into the range where an adult would think about ear protection, and rarely does anyone hand a child a pair of plugs on the way in.

What changes as the ear ages

Hearing does not fade uniformly. The highest frequencies go first, often decades before anyone notices in conversation. A 2024 study in Scientific Reports looked at what that loss does to the experience of an ordinary sound: the whine of a dental drill. Testing 62 people aged 12 to 67, the researchers found hearing sensitivity above 8 kilohertz falling sharply with age — the gap between teenagers and older adults at 14 kHz exceeded 65 decibels — and found that younger and older listeners diverged significantly in how they rated the sound. Part of the drill’s unpleasantness lives in a band that older ears no longer register.

The consonants of speech live in those upper frequencies too. The soft sibilance of s, f, and th. When those go, vowels remain clear but words blur into one another, which is why a person with age-related hearing loss can insist, honestly, that everyone around them is mumbling.

Even occupational noise, long assumed to be a leading cause of adult hearing damage, is more complicated than the headline suggests. A 2022 study in Frontiers in Neuroscience compared 40 young factory workers exposed to occupational noise in Zhejiang province, China, against 40 unexposed controls, all with normal hearing thresholds, and found no effect of that exposure on auditory brainstem response or on speech perception in noise. Within that cohort, at least, damage patterns appear to depend on the specific type, intensity and duration of exposure rather than on any single threshold being crossed.

The ear as a listener from birth

The dynamic range is present almost from the beginning. Newborns can distinguish their mother’s voice from a stranger’s within days. By six months, an infant’s auditory cortex is already sorting the phonemes of whatever language is spoken around them — a process that continues through the first year. By twelve months, the ear has already narrowed toward the sounds that matter and away from the ones that do not.

That narrowing is not a loss of range. It is a tuning. The trillion-fold dynamic window remains open. What changes is which patterns inside that window the brain treats as meaningful.

What silence sounds like

The people who spend time in anechoic chambers describe the experience in remarkably consistent terms. Blood in the ears sounds like a distant ocean. Swallowing sounds like a thud in a cave. Turning the head produces a soft crackle from the joints of the neck. None of these sounds are new. They are always there. The ear only hears them when the room stops adding its own signal.

The threshold of hearing, then, is not a wall. It is a floor set by the physics of air itself — by how quietly molecules can move before they stop moving in a coherent wave at all. Below that, there is nothing to hear because there is nothing happening.

Above it, across twelve orders of magnitude in power, the ear does its work. A held breath. A whisper. A voice across the room. A door closing. A truck outside. A helicopter overhead. A demolition charge two streets away. All of it processed by the same two cochleae, each the size of a pea, spiraling behind the temporal bone, moved by pressure changes measured in millionths of an atmosphere and by ripples that can, at their upper limit, tear tissue.

Cup a hand behind an ear, in a quiet room, and listen. The faint hiss is not the room. It is largely the sound of the auditory system itself, alive and listening for something quieter than it will ever hear.

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The potential waste stream is large. One report on the research cites at least 18 million tonnes of spent coffee grounds each year. Much of that material is wet when discarded, which is exactly what makes conventional thermal processing awkward: before the useful carbon can be concentrated, a large amount of water normally has to be dealt with.

Why wet coffee grounds are such an awkward fuel

The Korean experiments started with spent grounds containing roughly 55 percent moisture. That matters because heating wet biomass usually means spending energy on evaporation before the material reaches the temperatures needed for carbonisation or pyrolysis.

Other coffee-waste processes solve different problems and use different chemistry. A University of Sharjah patent filed on March 13, 2025, for example, describes combining spent coffee grounds with PET and potassium hydroxide to make activated carbon for CO₂ capture, with co-pyrolysis below 500°C and activation below 700°C. That is a useful route, but it is not the same job as rapidly converting wet grounds into solid fuel.

What the flame plasma actually does to a coffee particle

The crucial correction is that this system is not a conventional electric-arc plasma torch running an argon or nitrogen jet at several thousand degrees. In the reported KIGAM setup, LPG and compressed air are burned to generate an atmospheric flame plasma in the 800–900°C range.

That heat reaches the wet particles quickly enough for moisture inside them to flash into vapour. The sudden pressure increase produces what the researchers call a “popcorn effect,” opening the structure of the particles while carbonisation is taking place. Instead of removing the water beforehand, the process uses its rapid evaporation as part of the treatment.

Under the reported optimum conditions, conversion took 90 seconds and the material lost 83.3 percent of its mass. The result was a porous, carbon-rich biochar rather than a wet organic residue.

How anthracite-grade fuel compares to what you already know

The researchers’ comparison with anthracite is based on fuel performance, not on the coffee-derived material literally becoming geological coal. In testing, its calorific value increased by about one-third from the untreated grounds and reached the range the team compared with anthracite.

That is an unusually high energy density for a fuel made from wet food waste. It is also important not to jump ahead of the evidence: demonstrating anthracite-like heating performance in a laboratory does not by itself show that the biochar can be dropped into every boiler, kiln or power plant that currently burns anthracite.

Why coffee, of all things, keeps ending up in the lab

Spent coffee grounds contain more than just cellulose and lignin. Research from the Universitat Rovira i Virgili, summarized by Bioenergy Insight, found that the waste contains roughly 15 percent lipids and tested ways of recovering that oil as a possible biodiesel feedstock.

The URV team found that extraction at 45°C for 60 minutes, using 35 millilitres of hexane per gram of dry residue, recovered about 90 percent of the oil yield produced by conventional Soxhlet extraction. The resulting extract also contained substantially fewer impurities, while the remaining lignocellulosic material was deliberately kept available for further processing.

Other researchers are pursuing biological routes. A 2026 study in Frontiers in Energy Research used un-pretreated spent coffee grounds in a process involving Clostridium thermocellum and generated biohydrogen in a co-substrate system.

A separate 2024 paper in Scientific Reports tested adding spent coffee grounds to existing anaerobic food-waste digestion. Methane production increased across the tested low co-feeding ratios without destabilising the process, but the benefit did not keep increasing indefinitely; at a much higher coffee-to-food-waste ratio, the process failed without trace-element supplementation.

Where the 18-million-tonne figure comes from

The 18-million-tonne number should be treated as a published estimate rather than a direct global count. The 2026 Frontiers in Energy Research paper describes global spent-coffee-ground production in 2021 as an estimated 18 million wet tonnes and says the majority was disposed of in landfills rather than recovered for useful applications.

The word “wet” matters. Coffee production figures generally describe beans before brewing, while spent-ground estimates may describe material after brewing water has been absorbed. That is why a wet-waste estimate can be substantially larger than the mass of dry coffee entering the system without the figures necessarily contradicting each other.

What plasma changes about the economics

The obvious process advantage is the missing pre-drying stage. In the KIGAM experiment, moisture-heavy grounds went directly into the flame-plasma treatment, so the system did not need a separate dryer or oil-removal step before carbonisation began.

That does not yet establish the commercial cost or carbon footprint of producing the fuel at scale. The reported system consumes LPG and compressed air, and any industrial assessment would also have to account for reactor throughput, fuel consumption, emissions, equipment costs, product handling and the value of avoiding disposal. The laboratory result shows that the conversion can happen extraordinarily quickly; it does not yet answer every question about a commercial plant.

The wider hunt for a use for the coffee that gets left behind

Fuel is only one possible destination. RMIT University researchers heated spent grounds without oxygen at about 350°C to make biochar for concrete, and later reporting from the university noted that replacing 15 percent of the sand with the coffee-derived material increased 28-day strength by about 30 percent in earlier laboratory trials.

Taken together, the experiments show why coffee waste attracts so much attention. The same spent material contains oils that can be extracted, carbohydrates that microorganisms can work on, and a carbon-rich skeleton that can be converted into biochar for fuel, adsorption or construction materials.

What happens when the flame goes out

What comes out of the Korean reactor is a porous biochar with substantially more concentrated fuel value than the wet material that went in. The important result is not that coffee grounds have suddenly become a proven drop-in replacement for coal everywhere, but that researchers were able to skip one of wet biomass processing’s most stubborn stages and complete the conversion in a minute and a half.

The next questions are industrial ones: how efficiently the process scales, how much LPG it consumes per tonne, how consistently the resulting biochar performs and where that material makes the most sense to use. For now, the striking part is simpler. In this experiment, the water inside a soggy pile of coffee grounds was not merely something to remove. Under an 800–900°C flame plasma, it became part of the mechanism that transformed the waste.

The post Global coffee drinkers leave behind roughly 18 million tonnes of wet grounds every year, and a Korean lab has now blasted them with 900°C plasma flames that pop the water into steam so violently the grounds turn to anthracite-grade fuel in 90 seconds. appeared first on The Artful Age.

The 2026 rankings, released on September 1, count alumni whose companies took venture capital over a ten-year window. That is a decade of Series A slide decks, closed rounds, missed rents, IPOs, quiet acquisitions and dead cap tables — all funnelled into one number for each school.

Berkeley’s number is bigger than anyone else’s. Again.

What PitchBook actually counted

PitchBook’s 2026 methodology drew on educational and investment data for more than 222,000 venture-backed founders globally. Each founder was tagged to the institution where they earned an undergraduate degree. Every startup they founded that raised venture capital in the ten-year window got attributed back to that school.

So the ranking is not a measure of MBA output. It is not a measure of who runs the best incubator. It is a count of what 22-year-olds from a given campus went on to build in the ten years after commencement, weighted by whether a professional investor was willing to write them a check.

Berkeley: 2,380 undergraduate alumni founders. 2,155 companies. Four years running.

The number in context

Berkeley’s founder count is roughly three times that of the top-ranked Indian institution. IIT Bombay, which came in at 22nd globally, produced 756 founders and 590 companies over the same decade. The University of Mumbai, ranked 74th, produced 339 founders and 316 companies that raised a combined $12.9 billion.

To put Berkeley’s 2,380 in a physical frame: that is roughly the size of an entire graduating class at a mid-sized liberal arts college. Every one of those people started a company that took outside money.

The United States dominates the top 100. Eight Indian institutions made the cut, up sharply from a decade ago.

Why Berkeley keeps winning

Three structural things sit under the number.

The first is scale. Berkeley has a large undergraduate enrollment and admits a substantial computer science and engineering cohort every year. Stanford’s undergraduate body is smaller. When you count raw founder output, a big public university with a strong technical program has a mathematical head start on a small private one.

The second is proximity. The Berkeley campus is a 40-minute BART ride from downtown San Francisco and about the same drive to Palo Alto. Sand Hill Road — the strip of venture capital offices in Menlo Park that has funded roughly half the internet — is inside the same commute radius as a Berkeley student’s dentist.

The third is the compounding effect of alumni networks. A Berkeley undergraduate in 2026 who wants to raise a seed round can find a Berkeley alum inside almost any Bay Area VC firm. According to Johnny Edward, a partner at Grant Thornton Bharat, discussing the IIT rankings, these advantages have compounded over several decades, including selective admissions, alumni networks, incubation infrastructure and investor connections.

Berkeley has had all four of those things, near a working venture capital cluster, for fifty years.

What “venture-backed” actually means

The word matters, because it filters out most companies. A venture-backed startup is one where a professional investor — a firm managing pooled capital from pension funds, endowments and wealthy individuals — has bought equity in exchange for a check, usually starting at a few hundred thousand dollars and often running into tens of millions.

Venture capitalists reject the overwhelming majority of pitches they see. Standard industry rule of thumb: a partner meets with a few hundred companies to fund one. So each of Berkeley’s 2,155 companies represents a founder who convinced a professional skeptic that the business was worth a bet.

That is a higher bar than “started a company.” It is a much higher bar than “had a business idea.”

The female founder number

Berkeley also topped the PitchBook ranking for undergraduate universities producing female founders, according to The Daily Californian’s coverage of the rankings. Women remain a minority of venture-backed founders globally — a persistent gap that has narrowed slowly over the past decade — and Berkeley’s lead in that subcategory is smaller than its lead in the overall count, but it exists.

The same ecosystem effects that drive the overall number seem to be working in the female-founder subcategory: a large undergraduate body, technical majors, proximity to capital, and enough alumni role models that a first-time founder can find someone who looks like her already doing the job.

The Indian surge

The 2026 list is notable not just for Berkeley’s persistence but for how much of the top 100 is now non-American. Eight Indian institutions made the cut, up sharply from a decade ago. Several IITs ranked in the top 50, along with Delhi University, the University of Mumbai at 74th, and BITS Pilani.

The IITs together account for thousands of founders and billions in raised capital, with IIT Delhi leading the Indian cohort in total dollars raised — a gap that Edward attributed to sectoral differences and the impact of a few very large funding rounds.

An IIT-Madras professor and head of the Centre for Research on Start-Ups told The Hindu Business Line that the shift reflects deliberate investment in creating a supportive entrepreneurship ecosystem. Campus incubators, faculty entrepreneurship policies and returning-alumni investors have compounded over the past ten years the way Berkeley’s did over the past fifty.

The public university story

Berkeley is a public university. So is the University of Wisconsin–Madison, which jumped to sixth among American public universities in the same 2026 ranking. So are the IITs, which are federally funded institutions with heavily subsidized tuition.

The pattern matters because the popular story about tech founding usually centers on private universities — Stanford, Harvard, MIT — and expensive coding bootcamps. The PitchBook data tells a different story. Large public universities with strong technical programs and geographic access to capital produce enormous numbers of founders, at a per-dollar-of-tuition rate that private peers cannot match.

California residents pay significantly less in tuition and fees to attend Berkeley as undergraduates than students pay at private institutions like Stanford. Both schools produce startup founders. One does it at a fraction of the sticker price.

What the ten-year window captures

The ten-year window PitchBook used is a specific slice of history. It starts the year after the second wave of mobile-first consumer apps peaked. It runs through the ZIRP-era venture boom of 2020 and 2021, when U.S. venture funding hit a record high, and then through the sharp correction of 2022 and 2023, when funding fell by more than half.

Berkeley’s founders sit inside that whole arc. Some of them started companies at the peak and raised at valuations that no longer exist. Some started in the trough and are only now raising their first serious rounds. The 2,155 number includes both.

It also includes founders who took venture money for companies that are already dead. PitchBook counts the funding event, not the outcome. A startup that raised a $2 million seed round in 2018 and shut down in 2021 still counts toward its founder’s school. So the ranking measures the school’s capacity to produce fundable founders, not the school’s capacity to produce successful companies.

Those are related but different things.

What the number does not say

The ranking is silent on employees hired, revenue generated, or wealth created. It is silent on whether any of these companies produced anything socially valuable. It is silent on the founders who tried and failed to raise, and on the founders who chose not to try — the ones who took steady engineering jobs, went to graduate school, joined the government, taught high school, or built bootstrapped companies that never took outside money.

A university ranked outside the top 100 might still be producing an extraordinary number of small business owners, artists, teachers, doctors, and community builders. PitchBook does not measure any of that. It measures one specific pipeline: undergraduate to venture-backed founder.

Berkeley wins that pipeline. It has for four years.

The compounding decade

Something Rajan said at IIT-Madras hangs over the whole ranking: the ecosystem is doing the biggest thing. A student who arrives at Berkeley in the fall of 2026 walks into a campus where every dorm floor has someone whose older sibling founded a company, whose roommate is interviewing at a seed-stage startup, whose intro CS professor sold a company to Google in 2011. The environmental pressure to try is enormous.

Whether that pressure is healthy is a separate question. The PitchBook ranking simply records that when 22-year-olds leave that campus, they start companies at rates no other university on Earth matches. And ten years from now, when the 2036 ranking is released and someone tallies the founders who received their first venture check between 2025 and 2036, the Berkeley freshmen who moved into their dorms this September will be a large fraction of the count.

The next number is already being written, on Sproul Plaza and in Soda Hall and on the BART platform at Downtown Berkeley station, by students who have not yet decided what they are going to build.

The post For the fourth year in a row, UC Berkeley undergraduate alumni have founded more venture-backed companies than graduates of any other university on Earth — 2,155 startups from 2,380 founders — beating Stanford, Harvard, Cornell and MIT in the 2026 PitchBook rankings. appeared first on The Artful Age.

The Voyagers are dying slowly, and the mission team is choosing which systems go first.

The plutonium is doing what plutonium does

Each Voyager runs on three radioisotope thermoelectric generators, or RTGs, fuelled with plutonium-238. The isotope has a half-life of about 87.7 years, and heat from its decay is converted into electricity through thermocouples. The system was built for endurance, not permanence. The generators supplied roughly 470 watts at launch and have been producing steadily less power ever since.

Four watts is not much. It is roughly the draw of a small LED nightlight. But repeated year after year on a spacecraft whose available electrical margin is already thin, those watts determine which heaters and science instruments can remain alive.

The engineers have known this constraint was coming for decades. Instruments used for the planetary encounters were retired after their work was finished, and the Voyager team has continued shutting down systems as available power declines. Years ago, the team established an order for retiring the remaining science instruments so that each shutdown could preserve the mission a little longer.

What the cosmic ray subsystem did before it stopped

The instrument switched off on 25 February 2025 had spent decades measuring high-energy particles, including galactic cosmic rays arriving from beyond the solar system. In August 2012, a sharp rise in galactic cosmic rays and a collapse in particles associated with the Sun became important evidence that Voyager 1 was crossing the heliopause. NASA’s account of the discovery makes clear that the final conclusion drew on several kinds of measurements, including later plasma-wave data, rather than the cosmic ray instrument alone.

Voyager 2’s low-energy charged particle experiment measured ions, electrons and cosmic rays across a lower-energy range. It remained productive long after the planetary encounters and continued operating until March 2025. Instruments built for a mission conceived in the 1970s had returned usable science for nearly half a century.

What is still on

After the two shutdowns in early 2025, Voyager 1 still had three operating science instruments. That changed on 17 April 2026, when engineers shut down its low-energy charged particle experiment. NASA’s current instrument-status table now lists two active instruments on Voyager 1: the magnetometer, which measures magnetic fields, and the plasma wave subsystem, which measures electron-density-related plasma waves.

Voyager 2 still has three active science instruments: its magnetometer, plasma wave subsystem and cosmic ray subsystem. The two spacecraft therefore no longer carry identical active instrument sets, but both continue returning measurements from interstellar space.

The distances involved are not really imaginable

By September 2026, Voyager 1 is about 16 billion miles from Earth and moving at roughly 38,000 miles per hour relative to the Sun. Its one-way radio time is now just under 24 hours. NASA says the spacecraft will reach 16.094 billion miles from Earth, exactly one light-day, on 18 November 2026. A command sent from Earth and the confirmation sent back therefore span nearly two days even before engineers begin interpreting the result.

Voyager 2 is more than 13 billion miles from Earth. Together, the two Voyagers are the only spacecraft ever to have operated outside the heliosphere, the protective bubble created by the Sun’s particles and magnetic field. No other operating spacecraft is returning measurements from that environment.

The antenna problem

Even the ground infrastructure can constrain what the mission team does. Deep Space Station 43, the 230-foot antenna at NASA’s Canberra Deep Space Communication Complex, is the only dish with enough signal power to send commands to the Voyagers. Beginning 4 May 2025, it entered a major upgrade period that ran into February 2026, with only limited periods of availability.

That forced the Voyager team to plan ahead. Before the long command pause, engineers tried to revive Voyager 1’s original roll thrusters, whose heaters had been considered inoperable since 2004. The backup thrusters that replaced them had developed residue buildup in their fuel tubes, raising concern that they could eventually become unusable.

The test worked. After allowing for the roughly 23-hour one-way signal time, the team saw the dormant thruster heaters begin warming within about 20 minutes of receiving the command. The hardware had been written off for more than two decades, yet it responded.

A brief history of accidental durability

The Voyagers were not originally expected to spend half a century returning data. Their planetary encounters culminated when Voyager 2 passed Neptune in 1989, after which the spacecraft continued into what became the Voyager Interstellar Mission. Their survival has depended on hardware built in the 1970s and on successive generations of engineers finding ways to stretch declining power and aging propulsion systems.

The contrast with earlier planetary missions is stark. NASA’s history of Mariner 1 records that the spacecraft lifted off from Cape Canaveral on 22 July 1962 but veered off course, forcing the range safety officer to destroy the launch vehicle 293 seconds after liftoff. Mariner 1 ended in the Atlantic. The Voyagers have now been flying for 49 years.

In April 2026, Voyager mission manager Kareem Badaruddin described the choice plainly after another instrument shutdown. NASA/JPL reported that the team remained focused on keeping both Voyagers operating for as long as possible. That is the ethic of the late Voyager mission: giving up one capability to preserve the rest.

What “Big Bang” means at JPL

In 2026, the team also tried a more ambitious power-saving procedure nicknamed “Big Bang.” Rather than retiring another science instrument, engineers reconfigured several spacecraft devices at once so lower-power hardware could take over necessary functions. On 4 August 2026, NASA reported that the procedure had successfully freed power on Voyager 2.

NASA said the change should allow Voyager 2’s three remaining science instruments to keep operating for at least an additional year without another instrument shutdown. Engineers also planned to make a similar swap on Voyager 1. The procedure does not stop the annual power decline, but it gives the team another margin to work with.

The arithmetic remains unforgiving. Radioisotope power continues to fall, and unforeseen failures can arrive before the power budget itself becomes decisive. Every successful conservation measure shifts the deadline; none removes it.

Why the losses feel personal

There is something particular about the pace of the Voyager shutdowns that makes them harder to read as pure engineering news. The spacecraft have outlived many of the people associated with their creation, including Carl Sagan, who chaired the committee that selected the contents of the Voyager Golden Record.

Suzanne Dodd has watched much of the mission’s late-life engineering from unusually close range. JPL announced her as Voyager project manager in 2010, after she had first worked on Voyager in 1984. Her tenure has covered years in which keeping the spacecraft alive increasingly meant deciding which pieces could be surrendered.

The February 2025 shutdown retired Voyager 1’s cosmic ray subsystem, one of the instruments that recorded the dramatic particle changes around the spacecraft’s 2012 passage into interstellar space. Voyager 2’s low-energy charged particle experiment was turned off for power conservation on 24 March 2025. Each shutdown removed a measurement capability that had survived since launch.

Four watts a year, and what it buys

The four-watt annual figure is an approximation used to describe the Voyagers’ continuing electrical decline. On spacecraft already operating with a narrow power margin, however, a few watts can determine whether another heater or science instrument remains available.

The February and March 2025 shutdowns were intended to give the mission roughly another year before another science instrument needed to be retired. When Voyager 1’s LECP was finally shut down in April 2026, NASA again described the move as giving the spacecraft about a year of additional breathing room. The successful Voyager 2 power reconfiguration has now added another margin without immediately sacrificing one of its three surviving science instruments.

These are small numbers against almost 16 billion miles. They are also the numbers that determine how long humanity keeps receiving direct measurements from beyond the heliosphere.

The signal is faint but still arriving

As of September 2026, both Voyagers are still transmitting. NASA notes that by the time Voyager’s radio signal reaches Earth, the power striking a Deep Space Network antenna is only about 10^-16 watts. The antennas have to pull that whisper out of the background noise and recover measurements sent by hardware nearly half a century old.

The spacecraft are still pointed well enough for their high-gain antennas to communicate with Earth. Voyager 1 has not photographed the planet since 1990, when it captured the “Pale Blue Dot” during its final imaging sequence before its cameras were switched off.

No next science-instrument shutdown has been publicly scheduled. The mission team is watching the power budget and using the extra margin created by the 2026 changes. When another shutdown eventually comes, the command will take almost a day to reach Voyager 1, and almost another day will pass before Earth can receive confirmation of what happened.

Four watts a year. A plutonium half-life measured in decades. Two probes still whispering from outside the Sun’s protective bubble, with engineers buying their remaining science one careful watt at a time.

The post On 25 February 2025, engineers at JPL switched off Voyager 1’s cosmic ray subsystem, and on 24 March they shut down Voyager 2’s low-energy charged particle instrument — small mercies bought against a plutonium supply that loses 4 watts a year on each probe. appeared first on The Artful Age.

The reason anyone knows otherwise is that an off-duty park ranger named David Noble abseiled into the wrong slot canyon on a weekend, found a strange frond he did not recognise, and carried it home to Katoomba in his pack.

A weekend canyon, a frond in a rucksack

Noble was a fit young officer with the NSW National Parks and Wildlife Service, and he spent his rest days rope-descending the sandstone slots of Wollemi National Park — a wilderness close enough to Sydney to catch the city’s glow at night, but rugged enough that satellite maps still show blank pockets where nobody has walked. On that September day in 1994, he roped down into a gorge he had not visited before and found himself standing under trees he could not place.

He knew the flora of the Blue Mountains. These trees were not it. Their bark looked as if it had been dipped in bubbling chocolate. Their fronds were flat, arranged in two neat ranks along the stem, and coloured a curious blue-green that shifted toward bronze near the crown. He pocketed a piece of fallen foliage and hiked out.

Back at the ranger station, he showed the sample to a botanist. Within weeks it was clear the frond did not match any living species in the herbarium. It matched something older. As Space Daily’s account of the discovery records, botanists took several months to accept that the canyon Noble had entered contained a species known previously only from rock impressions.

Older than the flowers

The genus Wollemia belongs to the Araucariaceae, an ancient conifer family that dominated the southern supercontinent of Gondwana during the Jurassic and Cretaceous. Fossilised pollen and leaf impressions matching the Wollemi date back roughly 90 million years — a period when flowering plants were still a botanical minority and when non-avian dinosaurs still walked the same forests.

Set that against a human timescale for a moment. The last common ancestor of humans and chimpanzees lived about seven million years ago. The Wollemi lineage has been recognisably itself for more than ten times that span. It watched the Chicxulub asteroid strike, watched the non-avian dinosaurs die, watched Australia rift away from Antarctica, watched the continent dry into eucalypt scrubland. And it kept growing, in one canyon, essentially unchanged.

Botanists sometimes describe such species as living fossils—an imprecise but useful term. The tree Noble found in 1994 does not just resemble the fossils. It matches them.

What the tree actually looks like

A mature Wollemi can grow tall — roughly the height of a multi-storey building. A single tree can produce multiple trunks from one base, and individual trunks may live for centuries.

The bark is the signature. Dark brown nodules cover the trunk like clusters of bubbles, giving mature specimens the look of something dipped in Coco Pops. The leaves are ferny, flattened, held in ranks along the stem, and the whole tree carries a curious blue tint that catches light differently to any other conifer in the Blue Mountains. Individual trees produce both male and female cones, and the entire wild population is so genetically uniform that the grove behaves almost as a single clonal organism.

That uniformity is not a curiosity. It is a warning. A population with almost no genetic variation has almost no backup plans when a new pathogen, a hotter summer, or a fire season arrives.

Why the location is a state secret

The site is not hidden for drama. It is hidden because the trees are extraordinarily vulnerable to a soil-borne water mould called Phytophthora cinnamomi, responsible for root rot in thousands of Australian plant species. According to the ABC’s rare access visit to the grove in 2024, it takes just one gram of infected soil, tracked in on a boot sole, to introduce the pathogen. There is no cure.

Journalists permitted near the canyon are flown in by helicopter with the windows effectively curtained. They are sworn to secrecy. Cameras have their GPS tags stripped. Boots are soaked in methylated spirits. Notebooks are checked. The paranoia is proportional to what is at stake: a species that survived the extinction of the dinosaurs could be extinguished this decade by a muddy sole.

The 2019 fires and the sprinkler defence

In the catastrophic 2019–2020 Black Summer, flames swept through Wollemi National Park and came within metres of the grove. Remote-area firefighters were deployed to protect the trees with irrigation systems, and aerial water bombing and fire retardant were laid down around the catchment. Most of the mature wild population survived. Almost every sapling at a nearby translocation site did not.

Rebuilding the juvenile bank from seed will take decades — assuming no further fires. The climate models for the sandstone canyons of the Blue Mountains do not cooperate with that timeline. Hotter, drier summers are the forecast, and the fire seasons that scorched the edge of the grove in 2019 are expected to intensify.

Growth is glacial. Seedlings grow slowly until they can push a crown into the rainforest canopy. A tree planted at a translocation site today may not cone until the middle of the next century.

The strategy: hide, propagate, sell

The insurance policy has three parts. First, keep the wild location secret and the biosecurity strict. Second, quietly establish translocation sites elsewhere in the wilderness, in sandstone-slot microclimates that match the source canyon. Third — and this is the strange one — sell the tree.

The Australian government authorised licensed nurseries to propagate Wollemi pines from cuttings and sell them to gardeners worldwide. The logic is simple: if the species exists in tens of thousands of gardens on six continents, it can never truly go extinct. Kew Gardens has one. So does the Royal Botanic Garden in Sydney. A sapling now sits in a courtyard at the Vatican. A specimen recently bore fruit at a Worcestershire estate, raising hopes of viable seedlings in the English climate.

A donated Wollemi named Wally now grows in the Department of Ecology and Evolutionary Biology greenhouse at the University of Colorado Boulder, where undergraduates can stand next to a tree whose ancestors watched the Cretaceous close. The surviving Wollemi grove sits alongside the coelacanth and the bridled nailtail wallaby as one of the most striking Lazarus taxa on record — species presumed gone that turned out to be hiding in a canyon, a reef, or a paddock all along.

Where citizen science fits

David Noble was not a research botanist. He was a park ranger on his day off. That places him in a lineage Australian Geographic has documented at length: the fencing contractor who spotted a bridled nailtail wallaby near Dingo, Queensland, in 1973 after the marsupial had been presumed extinct for four decades; the bird-watcher who spent 150 hours over three years relocating a new species of peacock spider in Namadgi National Park. The pattern is consistent. Somebody doing ordinary outdoor work notices an anomaly and is right about it.

Science Blog has explored this before. The essay on how Pierre Janssen noticed an unfamiliar yellow line in the spectrum of a solar eclipse in 1868 and, in effect, discovered helium 27 years before anyone isolated it on Earth, sits in the same tradition: a person doing careful, patient work, spotting something that does not fit the catalogue, and being taken seriously.

The genetic bottleneck, and one small crack of hope

For decades, researchers scanning the DNA of wild Wollemi pines found essentially no variation between individuals. Every tree in the canyon appeared to be a near-clone of every other. A 2023 genome study described the species as a critically endangered living fossil with strikingly low diversity. Recently, though, botanists at the Botanic Gardens of Sydney using newer genomic techniques identified small differences between some individuals for the first time — a slim margin, but a real one, and enough to guide breeding decisions for the insurance populations.

Every wild tree, then, carries weight out of proportion to its size. Lose one, and you may have lost a version of the species that exists nowhere else.

What thirty-two years has bought

Thirty-two years on from Noble’s descent, the wild population is stable. Secret translocation sites are quietly filling in. Cultivated specimens sit in botanic gardens on six continents. In September 2024, on the 30th anniversary of the discovery, a batch of rare direct-lineage saplings was auctioned to fund ongoing conservation work.

The recovery programme has become a template for other critically endangered plants: secret location, quarantine protocols, translocation sites, commercial propagation, active fire defence. It is expensive and dependent on the discipline of a small workforce. It is also, so far, working.

Stand at the base of a mature Wollemi — a cultivated one, in Kew or Boulder or the Vatican courtyard, since the wild ones are off-limits — and press a palm against the bark. The bubbly texture is not ornamental. It is the structural fingerprint of a conifer genus that split from its relatives before flowers evolved, before grasses evolved, before the continents settled into the shapes on a modern globe.

The tree does not know any of this. It does not know that a ranger with a rope found it on a weekend in 1994, that its coordinates now sit in a locked file, or that a version of itself has been auctioned to a bidder in London. It grows slowly and waits for a gap in the canopy.

Ninety million years is a long time to wait. It has waited longer.

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Much of that story unfolds inside a nanometre-scale layer called the solid electrolyte interphase, or SEI. It forms on the anode during a battery’s earliest charging cycles and is essential to the cell’s operation. But if it keeps evolving, it can consume electrolyte and active lithium while increasing resistance. A 2023 review in Advanced Energy Materials describes those effects as contributors to capacity fade and poorer power delivery.

The SEI is therefore both protector and participant in ageing. It is not the only reason a battery loses capacity, but it is one of the most important.

The film that builds itself the first time you charge

Inside a typical lithium-ion cell, two electrodes are separated by an electrolyte, often made from a lithium salt such as LiPF₆ dissolved in organic carbonate solvents. During the cell’s initial charging cycles, the electrolyte is not completely stable at the low voltage of the negative electrode, which is commonly graphite.

Some electrolyte molecules decompose at that surface. Their reaction products, including organic compounds and inorganic salts such as lithium fluoride and lithium carbonate, accumulate into a thin, chemically complex film. This is the SEI.

A functional SEI conducts lithium ions but largely blocks electrons. That combination matters because it lets lithium continue moving into and out of the graphite while limiting further electrolyte decomposition.

Without adequate passivation, the electrolyte would continue reacting with the anode. The battery could lose electrolyte and active lithium much faster. The SEI is therefore not a simple defect. It is a protective layer that can become a source of degradation when it remains unstable or continues growing.

Why a good film can become a problem

The SEI is not a uniform sheet with identical properties throughout. Its composition, thickness and permeability depend on the electrode material, electrolyte formulation, temperature, voltage and charging conditions.

Graphite changes volume as lithium enters and leaves it. The change is modest compared with silicon, but it can still place stress on the interphase. Silicon-containing anodes undergo much larger volume swings, making repeated cracking, fresh-surface exposure and interphase reformation especially difficult to control.

A 2021 Nature Nanotechnology study used three-dimensional imaging to examine silicon and its SEI. The researchers found that electrolyte could penetrate pathways within the silicon structure and that SEI growth could extend inward, disrupting electron-conduction pathways and creating electrically isolated, inactive silicon.

That is more complicated than a film simply becoming uniformly thicker. Depending on the cell chemistry, degradation can involve interphase growth, cracking, pore formation, lost electrical contact and changes within the active electrode material itself.

The lithium that stops cycling

Whenever additional SEI forms, some lithium can become chemically incorporated into its reaction products. Those lithium atoms remain inside the battery, but they are no longer part of the inventory that shuttles between the electrodes during normal charging and discharging.

This loss of cyclable lithium helps explain why capacity often declines gradually rather than vanishing at once. Continued interphase growth can also increase resistance, while damage elsewhere in the cell can isolate active material or slow charge transfer.

A TechTimes overview of smartphone-battery degradation gives roughly 300 to 500 full cycles as a common range before a noticeable capacity decline. That is a broad rule of thumb, not a universal specification. Actual retention varies with the battery design, device, temperature and charging pattern.

The lithium reservoir has not simply emptied. Part of it may be trapped in interphase products, while other portions of the cell may have become less able to store or transport it effectively.

Heat accelerates the unwanted reactions

Higher temperatures generally accelerate the parasitic reactions involved in battery ageing. Heat can encourage further electrolyte decomposition and interphase change even while a battery is resting, particularly when the cell is held at a high state of charge.

This is why charging a hot phone on a car dashboard or running a laptop under heavy load on a surface that blocks ventilation can be harder on the battery than charging the same device in a cooler environment. The exact ageing rate cannot be reduced to one universal temperature formula because it depends on the cell chemistry and operating conditions.

Cold presents a different problem. Lithium ions move more slowly at low temperatures. If a cold cell is charged too aggressively, metallic lithium can plate onto the anode rather than entering the graphite normally. That can reduce usable capacity and, under severe conditions, create a safety risk.

The safest practical response is simple: avoid charging a device when it is already very hot, and allow an extremely cold device to warm toward its normal operating range before fast charging it.

What engineers are doing about it

Battery engineers cannot simply eliminate the SEI from conventional lithium-ion cells because a stable passivation layer is necessary. Instead, they try to control its chemistry, structure and mechanical behaviour.

One approach uses electrolyte additives that react before the main solvent and help form a more stable interphase. Fluoroethylene carbonate and vinylene carbonate are widely studied examples, particularly in cells containing silicon. Their effects depend on the full electrolyte and electrode formulation, so no single additive is ideal for every battery.

Researchers are also developing more specialised molecules. A 2021 Nature Communications study of dioxolone-derived additives reported 81.5 percent capacity retention after 400 cycles at 1C in the tested NCM811/silicon-carbon cells. In a separate fast-charging test at 3C, the formulation showed 1.9 percent capacity fading after 100 cycles.

Those are laboratory results for a particular cell design, not a promise for every phone or electric vehicle. They nevertheless illustrate the goal: create an interphase that remains ion-conductive, resists repeated mechanical stress and limits further reactions.

The solid-state gamble

Solid-state batteries replace the conventional liquid electrolyte with a solid ion-conducting material. Some designs use ceramics, polymers or sulphide-based compounds. Removing flammable liquid components could improve safety, but it does not make interface chemistry disappear.

In January 2026, researchers at Switzerland’s Paul Scherrer Institute reported a mild-sintering process for the argyrodite electrolyte Li₆PS₅Cl, combined with a 65-nanometre lithium fluoride coating on a lithium-metal anode. According to the ESS News account of the Advanced Science study, the tested full cell retained about 75 percent of its initial capacity after 1,500 cycles, while stable cycling continued beyond 2,700 cycles under the reported test conditions.

Lead author Jinsong Zhang described the high-voltage cycle stability as among the best reported at the time. The coating helped suppress electrolyte decomposition at the lithium interface and acted as a barrier against dendrite penetration. It was an engineered passivation layer rather than an uncontrolled film left to develop on its own.

Interfacial degradation also matters on the cathode side. A 2025 Nature Communications study found that chemical degradation at the cathode and solid-electrolyte interface affected charge-transfer behaviour and mechanical degradation in sulphide-based solid-state cells.

Solid-state technology therefore changes the interphase problem rather than abolishing it. The interfaces can potentially be designed more deliberately, but they remain central to performance and lifespan.

What this means for the phone in your pocket

A user cannot remove an SEI that has already formed, but charging conditions can influence how quickly a battery ages. Heat and prolonged time at a very high state of charge are two conditions worth limiting when convenient.

Modern devices increasingly handle some of this automatically. Apple says its Optimized Battery Charging feature can delay charging past 80 percent when an iPhone is expected to remain connected to power for an extended period. Other manufacturers offer similar adaptive-charging or user-selectable charge-limit features.

There is no need to treat a phone like laboratory equipment. Charging to 100 percent when the full range is needed is normal use. A practical approach is to avoid unnecessary heat, use the manufacturer’s battery-protection settings and avoid leaving a device fully charged in a hot environment for long periods.

Fast charging is also a managed trade-off rather than an automatic battery killer. Higher charging power can produce more heat, but modern devices regulate current and temperature. Letting a hot device cool before charging is more useful than worrying about an occasional fast charge.

A film you cannot see, doing essential work

The SEI is one of battery chemistry’s central compromises. It forms because the electrolyte is unstable against the charged anode, then protects that anode from more extensive decomposition. When the interphase remains stable, the battery can cycle efficiently. When it keeps changing, it can consume active lithium, increase resistance and contribute to capacity loss.

Researchers now use imaging, spectroscopy, simulations and operando experiments to follow processes that were once hidden inside sealed cells. In July 2026, the Institut Laue-Langevin reported tracking lithium movement in real time inside a working solid-state battery using neutron diffraction. The experiment revealed uneven lithium extraction within a thick positive electrode, showing how much complexity can remain even when the liquid electrolyte is gone.

If an ageing phone no longer lasts through the day, the SEI may be part of the explanation, but it is not necessarily the only culprit. The real story is a network of slowly accumulating chemical and mechanical changes. The invisible film on the anode is one of the most consequential of them because the battery needs it to work, even as its continued evolution helps determine how long that work can continue.

The post One reason lithium-ion batteries slowly lose capacity isn’t that the lithium disappears, it’s that a microscopic film called the solid electrolyte interphase can keep growing on the anode, consuming active lithium and slowing ion transport appeared first on The Artful Age.

The most extraordinary material was invisible to the people gathering those dark stones from roads, roofs and paddocks. Microscopic silicon carbide grains inside the meteorite had formed before the Solar System, and laboratory estimates placed some between 5 and 7 billion years old. The Field Museum describes them as the oldest solid material yet found on Earth.

A spring Sunday in central Victoria

Murchison lies roughly two hours north of Melbourne. In ABC Science’s 2019 oral history of the fall, residents remembered preparing for church, celebrating a 21st birthday and building a ferret cage when the noise stopped the town. Witnesses described a blue plume in a clear sky and a sharp smell resembling methylated spirits.

Marianne Begg recalled that 115 dairy cows had crowded into a distant corner of their paddock with their ears raised. Residents proposed explanations ranging from a plane crash to an explosion at the nearby military training area. With no immediate source of confirmation, people eventually resumed their Sunday routines.

A black substance in the dairy yard

That evening, farmer Arnold Brisbane returned for the second milking and found black, charcoal-like material on a yard he had cleaned earlier. He threw much of it over a fence and washed the remainder into the manure pit because he had no reason to recognise it as a meteorite. The following morning, he carried a sample to the Shepparton News.

The newspaper took the material to police and contacted the University of Melbourne’s geology department. That chain of decisions helped researchers obtain unusually fresh specimens before prolonged exposure to rain, soil and handling could alter them. Other pieces had also landed across the district, so the scientific record did not depend on one fragment alone.

John Lovering’s two encounters with the meteorite

John Lovering, then professor of geology at the University of Melbourne, was returning from the United States with Apollo 11 lunar samples on the day of the fall. While he was standing at Melbourne airport with the samples, a journalist from The Age told him that something had fallen near Murchison. He did not examine the meteorite at the airport.

A few days later, Lovering was waiting to appear on the ABC television program This Day Tonight when someone arrived with a meteorite fragment in a gas-swollen plastic bag. He opened it, noticed the strong mixture of organic odours and recognised the black material as a carbonaceous chondrite. His excitement reportedly had to subside before the broadcast began.

The search across the paddocks

The recovered fragments were spread through a long strip of farmland running through Murchison and neighbouring areas. One substantial piece pierced the roof of a hay shed, while smaller pieces were found on roads and in fields. University of Melbourne geology student Andrew Gleadow was assigned to search Brisbane’s manure pit in gumboots, sieving the slurry for hard fragments.

Brothers Peter and Kim Gillick, aged 10 and 11, approached the search methodically. They studied where different-sized pieces had landed, marked likely areas on maps and walked organised lines through the paddocks. Kim later estimated that the brothers recovered roughly one-third of the approximately 100 kilograms eventually collected.

Residents have long suspected that a larger piece may have continued toward the Waranga Basin and disappeared into its mud. That remains a local possibility rather than a confirmed recovery site. What is certain is that the fall produced many fragments rather than one crater-forming impact.

What the Murchison meteorite contains

Murchison is classified as a CM2 carbonaceous chondrite, a primitive meteorite rich in carbon compounds and minerals altered by water on its parent asteroid. Most of the stone dates from the beginning of the Solar System, roughly 4.6 billion years ago. The headline age belongs only to rare presolar grains embedded within that younger material.

The grains are recognisable because their isotope ratios are radically different from ordinary Solar System matter. Most of the silicon carbide grains studied by Philipp Heck and his colleagues originated in outflows from low- to intermediate-mass asymptotic giant branch stars. These were ageing stars shedding newly condensed mineral dust into interstellar space.

How scientists estimated the grains’ ages

In January 2020, Heck and his collaborators published their analysis in the Proceedings of the National Academy of Sciences. They determined cosmic-ray exposure ages for 40 large presolar silicon carbide grains extracted from Murchison. The research combined new measurements with consistently recalculated results from earlier work.

Isolating the grains requires crushing meteorite material and dissolving much of the surrounding rock with acids. Silicon carbide is exceptionally durable, so some grains remain after less resistant minerals disappear. Researchers can then examine the survivors with mass spectrometers.

While travelling through interstellar space, the grains were bombarded by galactic cosmic rays. Those collisions produced small quantities of isotopes such as neon-21, and their accumulated abundance provided an estimate of how long each grain had remained exposed. Combining that exposure interval with the roughly 4.6 billion years since the Solar System formed produced total age estimates.

Most grains had comparatively short interstellar exposure histories and total estimated ages between about 4.6 and 4.9 billion years. A minority had spent far longer in interstellar space, with the oldest estimate reaching roughly 7 billion years. That extreme figure carries substantial uncertainty, so it is best understood as an estimate rather than an exact birthday.

A possible episode of increased star formation

The distribution of exposure ages offered another clue. Around 60 percent of the grains had interstellar lifetimes shorter than 300 million years, while a smaller group survived for more than a billion years. A simple steady-state model did not reproduce that pattern.

Heck’s team proposed that many parent stars may have formed during a moderately enhanced period of Milky Way star formation around 7 billion years ago. Those stars later reached their dust-producing phase shortly before the Solar System formed. The paper describes this interpretation as a plausible and partly speculative explanation, not a final reconstruction of the entire galaxy’s history.

Putting seven billion years in perspective

The universe is approximately 13.8 billion years old, so the oldest estimate would place one Murchison grain at around half the universe’s present age. It would have formed billions of years before Earth and more than two billion years before the Sun. By the time the Solar System began assembling, that grain had already completed an immense journey through interstellar space.

The grain’s parent was an evolved star that expelled silicon carbide in its outflow. Its precise identity, location and surviving remnant cannot be reconstructed from the grain, so it would be speculation to place a particular white dwarf somewhere in today’s Milky Way. What the isotope record establishes is more limited and more remarkable: the material formed beyond the Solar System and survived long enough to become part of it.

The second archive inside Murchison

Murchison also became central to the study of extraterrestrial organic chemistry. In 1970, a team including Keith Kvenvolden and Carleton Moore published “Evidence for Extraterrestrial Amino-acids and Hydrocarbons in the Murchison Meteorite” in Nature. Later isotope studies strengthened the conclusion that important amino acids in the samples were indigenous to the meteorite rather than ordinary terrestrial contamination.

Subsequent work has identified a much broader chemical inventory, including nucleobases and insoluble organic material. In 2019, researchers also reported ribose and other bio-essential sugars in Murchison. These findings show that asteroid chemistry can produce and preserve some ingredients used by life, but they do not demonstrate that life itself arrived on Earth in meteorites.

The organic compounds also help explain why fresh Murchison material produced such a distinctive smell. Philipp Heck told ABC Science that fragments could retain the characteristic odour decades after the fall. The smell was evidence of complex chemistry, not evidence of organisms inside the rock.

A different kind of falling-sky story

Murchison belongs to a wider history of events in which material or information from the sky changed scientific understanding. The 1908 Tunguska airburst flattened an enormous area of Siberian forest without producing a confirmed crater. Its evidence was written across fallen trees rather than preserved inside recovered stones.

During the total solar eclipse of 18 August 1868, Pierre Janssen observed an unfamiliar yellow spectral line over Guntur, India. That observation contributed to the identification of helium before the element was isolated on Earth. Murchison was quieter than either event, but its fragments opened an equally unusual route into deep history.

The supply is valuable and finite

Fragments of Murchison are now held by museums and research institutions around the world. The Field Museum documents climate-controlled storage in dust-tight metal cabinets, clean handling procedures and a detailed record of each specimen’s use. Those controls matter because organic-chemistry studies are especially vulnerable to contamination.

Not every investigation destroys its sample. Imaging, density measurements and several other techniques can be non-destructive, while cutting, grinding, dissolving and mass-spectrometry preparation consume at least part of a specimen. Isolating presolar grains is one of the destructive procedures, so curators must balance current research against the need to retain material for future instruments and independent verification.

Murchison is no longer the only directly sampled object known to contain presolar material. NASA’s OSIRIS-REx mission returned samples from asteroid Bennu, and a 2026 Nature Communications study examined how aqueous alteration had reduced presolar silicon carbide in some Bennu particles. The comparison shows that ancient stardust can survive inside different primitive bodies, but its abundance can be reshaped by each asteroid’s chemical history.

A Murchison fragment still looks like an ordinary dark stone, sometimes pitted or crumbly at its edges. Its significance lies in scale: a rock assembled with the young Solar System contains microscopic solids made around stars that had already aged and shed their material. Those grains reached a Victorian dairy district on a Sunday morning, while families prepared for church and cows crowded into the corner of a paddock.

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The research involved 148 children between the ages of 3 and 7. Using infrared eye-tracking, the researchers watched where the children looked while they decided which rotated object matched the target image, without requiring them to explain how they reached the answer.

The children identified as using the holistic approach solved the problems about twice as fast as those whose gaze patterns suggested a slower, piecemeal strategy. The result offers a more detailed look at how early some familiar forms of spatial reasoning appear.

What mental rotation actually is

Mental rotation is the ability to imagine an object changing orientation without physically moving it. You use a version of it when deciding how a jigsaw piece needs to turn, when orienting a map or when comparing two shapes shown from different angles.

Developmental psychologists study the skill partly because spatial abilities are associated with learning in mathematics, science and reading. Similar-looking letters such as b and d, for example, require children to learn that orientation can matter even when two shapes share many visual features.

That makes the question of how young children solve rotation puzzles important, not simply whether they get the answer right.

The fire truck test

The experimental set-up was deliberately simple. A child viewed a large picture of an everyday object, such as a fire truck, alongside two smaller versions positioned differently.

One small image could be rotated until it matched the large image. The other was a mirror image, meaning ordinary rotation would never make it identical.

The child’s job was to choose the matching one.

An eye-tracker mounted near the screen used infrared light to record where the child was looking during the trial. Instead of relying on a young child to describe a cognitive strategy in words, researchers could examine patterns of fixations, visits and viewing time.

Two ways to solve a puzzle

The eye-tracking analysis revealed two broad patterns.

Some children focused repeatedly on individual parts of an object. Their attention moved among features such as wheels, a ladder or the cab, and they spent more time studying details. The researchers classified this pattern as a piecemeal strategy.

Other children made fewer visits and fixations and spent less time examining individual details. Their pattern was consistent with treating the object as a single unit, the holistic strategy.

Most children in the study fell into the holistic group. That whole-object approach also appears commonly in adult mental-rotation research, although adults can use piecemeal strategies too depending on the task.

Why this changes the timeline

Researchers have long known that young children can answer mental-rotation questions. What has been less clear is what they are doing mentally when they arrive at an answer.

The FIU team, led by Karinna A. Rodriguez, found gaze patterns consistent with the same two broad strategies described in earlier mental-rotation research. Crucially, the majority of children showed the holistic pattern.

That does not mean a three-year-old performs spatial tasks with an adult’s speed, experience or accuracy. It does suggest that an important whole-object problem-solving strategy is already available much earlier than adults might assume.

For early education, that gives familiar activities a little more weight. Puzzles, blocks and tangrams are not merely preparation for spatial reasoning later on. They give children opportunities to practise spatial transformations they are already capable of attempting.

The blocks-and-puzzles evidence chain

The FIU finding fits a broader body of work connecting early spatial skills with mathematics and other areas of learning.

In a University of Delaware and Temple University study, three-year-olds were asked to reproduce six model structures using separate blocks. Children who were better at copying those block structures also tended to perform better on an early mathematics assessment.

That is an association rather than proof that one afternoon with blocks causes stronger maths ability. But it is one part of a consistent reason researchers pay attention to the spatial decisions involved in building, rotating, fitting and comparing objects.

A separate decade-long study examined whether preschool play patterns were associated with mental-rotation performance at age 13. Children classified by their parents as showing more masculine-typical play at age 3.5 scored higher on the later mental-rotation measure than children in the feminine-typical group.

The result held across boys and girls, but the researchers did not show that one style of play caused the later difference. As PsyPost’s report on the study notes, children with stronger early spatial tendencies might also have been more likely to choose spatially demanding play in the first place.

Why eyes can reveal what words cannot

Asking a four-year-old to give a precise account of how they solved a spatial puzzle has obvious limits. A child may know which truck matches without having the vocabulary to describe the sequence of mental operations behind the choice.

Eye-tracking provides another route. Researchers can measure which parts of the image attract attention, how often a child returns to them and how long those visits last.

In the FIU study, those measurements produced two distinct statistical profiles consistent with holistic and piecemeal processing. The comparison with adults comes from earlier research using similar strategy concepts, rather than from an adult control group tested alongside the children.

What this means for a Saturday afternoon

The practical takeaway is modest. Puzzles, blocks, tangrams and other spatial activities give children opportunities to turn, compare, combine and mentally reorganise shapes.

Language can be part of the same experience. Words such as above, below, edge, corner, curved, flat, upside-down and next to give children labels for relationships they are already seeing and manipulating.

A tangram is useful precisely because it can invite both kinds of attention. A child can look at the animal or house as a whole while also deciding which particular triangle or square fits one part of it.

Three-dimensional puzzles, wooden blocks, jigsaws, LEGO, magnetic tiles and pattern games create similar opportunities. None is a magic shortcut to later academic achievement; they are simply accessible ways to practise spatial reasoning.

The letter-flipping connection

The reading connection is more tentative than the spatial-puzzle finding itself.

In their public explanation of the research, Pruden and Rodriguez suggest that children who use a more piecemeal approach to mental rotation may overlap with children who have difficulty discriminating similar-looking letters such as p and q.

That remains a research possibility, not a demonstrated explanation for why a particular child reverses or confuses letters. The eye-tracking study did not establish that a piecemeal strategy causes dyslexia or other reading difficulties.

What the work does offer is a potential research direction: understanding children’s spatial strategies earlier may eventually help researchers study how those strategies relate to later reading development.

The strategy is already there. The practice sharpens it.

The most interesting part of the FIU finding is the shift in perspective. Preschool play is often described as preparation for the cognitive work that comes later, but some of that work is clearly already underway.

A three-year-old turning a wooden triangle before placing it into the right opening is using a basic spatial operation that adults rely on in far more complicated settings. The scale and expertise are different, but the need to imagine how an object changes when it turns is recognisable.

So the next time a child on the rug picks up a puzzle piece, rotates it once and settles it into the right slot, the movement is worth noticing. A small twist of the wrist can reflect a surprisingly sophisticated piece of spatial reasoning already taking shape.

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One of the more striking ideas to emerge from those experiments is that silicon and oxygen dissolved in iron may not stay dissolved forever. In a 2017 Nature study, researchers melted iron-silicon-oxygen alloy at pressures comparable with Earth’s core and found that silicon dioxide, SiO₂, could crystallize as the alloy cooled.

That does not mean scientists have watched silica crystals drifting through the real outer core. It means laboratory results established a physically plausible mechanism, and models built from those results explored what that mechanism could do to the core over geological time.

The density problem at the centre of Earth

Earth’s core is overwhelmingly iron-rich, but pure iron does not quite fit the measurements. A long-standing estimate put the outer core at roughly ten percent less dense than pure iron under comparable conditions, while more recent work has placed the shortfall closer to eight percent. C&EN’s overview of core chemistry traces that problem back to the work of geophysicist Francis Birch in the 1950s.

The missing density is one reason researchers have spent decades testing light elements such as silicon, oxygen, sulphur, carbon and hydrogen. Different mixtures affect not only density but also melting behaviour, heat transport and the convection that helps maintain Earth’s magnetic field.

The problem is that nobody can drill anywhere close to the core. The Kola Superdeep Borehole in Russia reached a little more than 12 kilometres, while the core-mantle boundary begins nearly 2,900 kilometres down. The rest has to be reconstructed indirectly.

What the diamond-anvil experiment actually showed

Diamond-anvil cells make a tiny piece of Earth’s deep interior possible on a laboratory bench. A microscopic sample is squeezed between diamond tips while lasers heat it to thousands of kelvin, allowing researchers to study matter at pressures otherwise found only deep inside planets.

Kei Hirose and colleagues used that approach on liquid Fe-Si-O alloy. Their experiments reached core pressures and revealed a broad range of compositions in which SiO₂ crystallized from the metallic liquid. The researchers then modeled what would happen as an initially hotter Fe-Si-O core cooled through time.

The important distinction is between what was observed and what was inferred. The crystals formed in the experimental samples. Their long-term behaviour inside Earth, their abundance and their contribution to core convection depend on models of the core’s composition and thermal history.

Why calling it quartz snow needs care

SiO₂ is the chemical formula of ordinary quartz, which makes “quartz snow” an appealing shorthand. But silica does not keep the familiar quartz crystal structure when subjected to the pressures of Earth’s deep interior.

A 2026 Geophysical Research Letters study of high-pressure SiO₂, for example, examined stishovite, post-stishovite and seifertite across pressures extending to 160 gigapascals. Those are very different crystal arrangements from the quartz found in a countertop or beach sand.

So the useful part of the analogy is chemical rather than mineralogical: silicon and oxygen can combine into solid SiO₂ under relevant conditions. Whether substantial amounts of that material separate from Earth’s present outer core is a different question.

The part scientists still disagree about

The 2017 result is not the last word. In 2019, a separate team tested Fe-Si-O alloys and found evidence for two immiscible iron-rich liquids rather than straightforward SiO₂ crystallization. Their PNAS study reported that the results suggested SiO₂ would not crystallize from molten Fe-Si-O at the core-mantle boundary.

That disagreement matters because the deep core cannot be sampled directly. Small differences in temperature, oxygen concentration, silicon concentration and phase behaviour can change which process a model predicts.

The safest picture is therefore not one of confirmed silica snow filling the outer core. It is a competition between experimentally motivated models for how silicon and oxygen behave in an iron-rich liquid under extraordinary conditions.

Why precipitation could matter for the magnetic field

Earth’s magnetic field is generated by motion in its electrically conducting outer core. Heat escaping from the core helps drive convection, while the freezing of the solid inner core also releases light elements into the liquid, adding compositional buoyancy.

The 2017 SiO₂ model proposed another possible source of compositional convection. If silica separates from the liquid near the top of the core, the remaining SiO₂-depleted metallic liquid changes composition and density. The study’s calculations found that the resulting buoyancy could have supplied enough energy to help power core convection and an early dynamo.

That is a model result, not a measurement of present-day silica precipitation. But it explains why a seemingly small piece of high-pressure chemistry attracted so much attention: changing which elements remain dissolved in iron changes how the entire core can move.

The outer core certainly does move on surprisingly short observable timescales. A 2026 study summarized by ScienceDaily from European Space Agency material found that a broad region of iron-rich fluid beneath the equatorial Pacific shifted from weak westward motion to strong eastward flow in 2010. The inferred eastward flow has weakened since 2020.

That flow reversal does not prove anything about silica precipitation. It does, however, underline how dynamic the liquid core is despite being hidden thousands of kilometres below the surface.

Hydrogen adds another complication

Silicon and oxygen are only part of the light-element problem. Hydrogen is especially difficult to study because it can escape from iron as experimental samples are decompressed, making recovered material a poor record of what happened under pressure.

A 2017 Nature Communications study tackled part of that problem with high-pressure, high-temperature neutron diffraction. Researchers observed hydrogen entering iron after hydrous minerals released water, supporting the idea that hydrogen could have entered metallic iron very early in Earth’s formation, before other light elements were incorporated through hotter melting processes.

More recently, researchers pushed the estimate further. A 2026 Nature Communications study combined laser-heated diamond-anvil experiments with atom probe tomography and estimated that Earth’s core could contain about 0.07 to 0.36 weight percent hydrogen.

Expressed in a more intuitive way, that is the hydrogen equivalent of roughly nine to 45 oceans of water. The researchers themselves stressed substantial uncertainties in the calculation, so 45 oceans is an upper-end estimate rather than a settled inventory.

A core that is chemically complicated

The familiar four-layer diagram of crust, mantle, liquid outer core and solid inner core is still useful. What it hides is the amount of chemistry happening inside those broad layers.

The outer core can contain several light elements at once. Their solubilities change with pressure and temperature. Some may separate into distinct liquids, some may enter solids as the inner core grows, and some may have been incorporated during the earliest stages of planetary accretion.

Even the boundary between core and mantle is not a simple smooth surface. Seismic observations reveal patches and layers with unusual velocities, but those structures have several possible origins. Partial melting, chemical reactions between core and mantle, accumulated material and changing iron-alloy chemistry can all enter the discussion.

What remains unknown

The concentration of silicon and oxygen in the core is still debated, and that uncertainty feeds directly into the silica-crystallization question. A mixture that crosses the SiO₂ saturation boundary in one model may remain stable or separate into two liquids under another set of assumptions.

The thermal history is uncertain too. How quickly the core has cooled depends on how efficiently the mantle removes heat, while the timing of inner-core growth affects how much thermal and compositional energy has been available to drive the dynamo at different stages of Earth’s history.

That is why a laboratory crystal cannot simply be scaled up into a literal description of what is falling through the core today. The experiment provides a constraint. Seismology, geomagnetism, thermodynamics and later experiments decide how much weight that constraint should carry.

A snow that may exist only under crushing pressure

The image remains extraordinary even with the uncertainty left intact. Under more than a million atmospheres of pressure, a metallic liquid containing iron, silicon and oxygen can cross a chemical boundary as it cools and produce solid SiO₂.

Whether Earth is doing that on a large scale today remains unresolved. What laboratories have already shown is almost as strange: squeeze a speck of iron alloy between diamonds, heat it to planetary temperatures, and chemistry familiar from the surface rearranges itself into forms that could help explain how Earth’s hidden metallic interior has evolved for billions of years.

The post We tend to picture Earth’s core as a solid ball of iron, but laboratory experiments squeezing molten iron, silicon and oxygen to core pressures show tiny crystals of silicon dioxide — the same chemical formula as quartz — can form as the alloy cools appeared first on The Artful Age.

The study, later published in Infant Behavior and Development, was small. Its finding was not.

The children with sixteen toys behaved the way most parents have watched their own children behave at a birthday party or a holiday morning. They picked something up. They put it down. They picked something else up. They put that down too. Metz described the pattern to TODAY as almost frantic — a kind of shiny object syndrome in miniature, where the mere presence of another option pulled attention off whatever was already in the child’s hands.

What the room actually looked like

The setup was deliberately plain. Age-appropriate sit-and-play items — stacking blocks, a dump truck, the sort of classic toddler equipment that has barely changed in fifty years. Half the children entered a room with four of these toys arranged on the floor. The other half entered a room with sixteen. The play sessions were timed and recorded.

Metz was not measuring joy on a smile-meter. She was measuring duration of engagement with a single toy, and the variety of actions a child performed with it. A child who pushes a truck across the floor once has done one thing. A child who pushes it, loads a block into the bed, drives it under a chair, unloads the block, and then narrates the whole scene has done five.

In the four-toy room, the children did the second thing. In the sixteen-toy room, they mostly did the first, then moved on.

The Harvard toy problem

Metz has a phrase for what drives parents to fill a playroom. “We keep bringing home more and more toys, thinking this is the toy that will get my kid into Harvard,” she told the New York Post. “But then we don’t see the value in their playing because they can’t organize themselves enough to play.”

That last phrase is the mechanism. A toddler brain is still building the skill of settling — of choosing an object, staying with it, discovering what it does. Every additional toy in the room is another interruption to that process, another small pull on attention. The fifteen toys a child is not currently holding are not neutral. They are competitors.

The pattern echoes a broader idea in early-childhood research: attention fragments when competing options stay visible, and a game cannot deepen if the next distraction is already sitting on the rug.

What “twice as long” actually means

Doubling the play duration with a single toy is not a small effect. In toddler research, sustained attention on one object is one of the better early predictors of later focus, language development, and problem-solving. It is the raw material for pretend play, which itself is the raw material for narrative thinking.

When a child has time to sit with a dump truck long enough to notice that the bed tilts, that the wheels spin backwards, that a block fits inside it — that is the point at which the truck stops being an object and becomes a prop. The prop is where imagination begins.

Cut the session short by presenting a shinier option two feet away, and the truck never gets to become a prop. It stays an object. The child moves on.

Why sixteen feels generous and lands as chaos

To an adult, sixteen toys on a floor looks like abundance. To an eighteen-month-old, it looks like a decision tree with sixteen branches and no way to prune it. Executive function — the mental machinery for prioritising, sequencing, and sticking with a choice — is barely online at that age. The prefrontal cortex is still under construction and will keep building well into a person’s twenties.

Metz described what she saw in the sixteen-toy room to Motherly: children took a rapid inventory, touched things in quick succession, and never settled. “That exploration is so fast-paced,” she said, “that they don’t have time to sit and explore all the things a toy can do before they need to move on to the next one.”

The four-toy children did something different at the very start. They also took an inventory. They looked at everything. But then they had time to circle back. “They went and they looked at them all, but then they had time to go back to each toy,” Metz explained. “They sat down and they played with it for twice as long, and they did many more things with it.”

The rotation fix

The study is not an argument for throwing toys away. Metz has been careful to say so in every interview she has given about the work. Her recommendation is structural: keep whatever you own, but only let a small number be visible and reachable at any one time.

“You can have your hundreds of toys if you have a place to store them, so that when a kid has time to play there’s just a smaller number available at the moment,” Metz has explained to Motherly. The published study makes a related point, as ScienceAlert reported: rotating stored toys back into play can offer novelty without the distraction of having too many toys out at once.

The rotation trick works because novelty comes from contrast, not from quantity. A dump truck that has been in a closet for three weeks is a new dump truck when it reappears on Tuesday morning. A child who saw it every day for three weeks stopped seeing it about a week and a half in.

The apartment that made the research

Part of the reason Metz noticed this pattern at all is that she raised twins in a 1,000-square-foot Chicago apartment. There was no spare room for a toy explosion. The constraint became the observation.

“There was just no space,” she has recalled to TODAY. “My kids had everything they could want or need — and lots of these are really great therapist-approved toys — but it’s just too much. They can’t settle down and play.”

Therapist-approved does not equal helpful in bulk. The Montessori tradition has argued something similar for over a century: a limited, curated set of materials, presented one at a time, produces deeper engagement than a well-stocked toy shelf. Metz’s study put a number on the intuition.

What the four-toy children were doing

The interesting question is not why sixteen toys failed. It is what the four-toy children did with the extra minutes. They stacked. They knocked things down. They tried to fit one object inside another. They started to narrate — to themselves, to the toy, to no one in particular.

Some began early forms of pretend play, the kind child development researchers watch for because it correlates with later language and social skills. A block became food. A truck became a bed. The physical object stayed the same. The meaning shifted.

That shift takes time. It cannot happen in the eight seconds a child spends with a toy before glancing at the fifteen alternatives on the rug.

The gift-giving problem

The study has become a fixture in holiday parenting coverage for a predictable reason. Christmas mornings, birthday parties, and grandparent visits tend to produce exactly the sixteen-toy condition Metz created in the lab — often on a single afternoon. The child unwraps, plays for a minute, unwraps again, plays for a minute, and by evening is overstimulated and cranky in a room full of new things.

Parents notice the crankiness and often blame sugar, or overtiredness, or the disruption of routine. Some of that is real. But the research suggests the abundance itself is part of the problem. A brain that cannot settle cannot rest.

Metz’s suggestion in interviews with Motherly and others has been consistent: accept the gifts, then quietly store most of them. Bring them out in ones and twos over the following months. The child gets a slow parade of new things instead of a single overwhelming pile.

Where the finding fits

Metz has been careful to note the limits of her own work. The toys in her study were classic sit-and-play items — the kind that reward repeated interaction. Modern battery-powered toys with lights, sounds, and preset routines may behave differently, because the toy itself is doing more of the entertaining. The child is a passenger rather than an author.

That distinction matters. A toy that does one thing when you press one button teaches the child that toys are for pressing buttons. A wooden block teaches nothing and therefore teaches everything: it can be a tower, a car, a piece of food, a phone, a boat. The open-ended object survives the rotation. The single-purpose object gets boring quickly, no matter how many buttons it has.

The quiet room, twelve minutes in

If you have ever watched a two-year-old at a doctor’s office with a basket of three battered waiting-room toys, you have seen the four-toy finding in the wild. The child does not complain about the selection. The child sits down with a plastic giraffe and, over the course of ten minutes, gives it a personality, a voice, a small crisis, and a resolution.

Bring that same child home to a room with a full toy shelf and the giraffe never gets a name. There is always something else on the shelf, just there, waiting to be picked up and put down.

Metz’s line, delivered to reporter after reporter, has become the take-home for parents who find the research: “Recognise toys for their short-term value and then pass them on.” The dump truck is not a permanent fixture. It is a prop for a season, and the season is shorter than the packaging suggests.

In the Toledo lab, the children with four toys did not know they were part of a study. They only knew that the room was quiet, the floor was uncluttered, and the truck in front of them had not yet given up all its secrets. So they stayed. Twice as long. Which, at eighteen months old, is the closest thing to concentration a person can offer.

The post A 2017 University of Toledo study gave toddlers either sixteen toys or four in a play session, and the children with four toys played twice as long with each one, invented more uses for them, and returned to elaborate on their own ideas. appeared first on The Artful Age.