Class of 2025
34 things have changed since you graduated
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What’s changed since 2025
Everything here shifted in 2025 or later, some of it too recently to be in any textbook you were handed. These are the corrections the next edition hasn’t printed yet.
Revision level: Lightly corrected. 13% of the archive changed after 2025. You got a fairly current edition. A few pages have been reprinted since.
- 34things changed
- 12were actually wrong
- 22just got sharper
- 10subjects affected
A day on Uranus is 17 hours and 14 minutes long
Changed in2025TaughtUranus rotates once every 17 hours and 14 minutes. Voyager 2 measured it during its 1986 flyby by timing the planet's radio emissions and magnetic field, and that has been the figure ever since.
NowIn April 2025, using a decade of Hubble observations of Uranus's auroras, astronomers pinned the rotation period at 17 hours, 14 minutes and 52 seconds: about 28 seconds longer than Voyager's value, and a thousand times more precise.
A gene therapy has to be developed for a whole patient population, never for one child
Changed in2025TaughtDeveloping a gene-editing therapy takes many years and enormous cost, so it only makes sense for diseases shared by thousands of patients. A treatment designed and manufactured for a single individual's exact mutation is science fiction.
NowIn May 2025 a team at Children's Hospital of Philadelphia treated an infant known as KJ Muldoon, who had a severe CPS1 urea-cycle disorder, with a CRISPR base-editing therapy custom-built for his specific mutation, from diagnosis to dosing in about six months. It was the first personalized in-vivo gene-editing medicine made for one person.
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Computers can't do original mathematical reasoning; no machine could win a math olympiad
Changed in2025TaughtComputers are fast calculators, but genuine mathematical creativity (reading a hard, unseen olympiad problem and inventing a multi-step proof) is a distinctly human act. A machine can crunch numbers; it cannot reason its way to a novel proof under exam conditions.
NowIn July 2025, AI systems from Google DeepMind and OpenAI both scored 35 out of 42 on the International Mathematical Olympiad, gold-medal level, solving five of six problems as free-form written proofs, under the same rules and time limits as human contestants.
Earth's inner core is a solid, rigid ball of iron
Changed in2025TaughtAt the centre of the Earth is the inner core, a solid ball of iron and nickel, frozen rigid by immense pressure despite being as hot as the Sun's surface. It's the one solid, unchanging part of the deep Earth.
NowA 2025 study found the inner core's surface is deforming and changing shape over time, its boundary flexing like something viscous, not standing rigid. Turbulence in the liquid outer core appears to be reshaping the inner core's near-surface at a surprisingly fast rate.
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Internet slang isn't real English
Changed in2025TaughtSlang from the internet is not proper English. It's a fad, it won't last, and it certainly doesn't belong anywhere near a dictionary.
NowIn August 2025 the Cambridge Dictionary added 'skibidi', 'delulu', and 'tradwife' among 6,212 new words, phrases, and senses in a single year. The editors' stated bar was staying power: these words were tracked in real usage and stuck around long enough to earn entries.
Nothing you can be given lowers your risk of dementia
Changed in2025TaughtDementia is a matter of genes and age. There is no vaccine and no ordinary medication that measurably lowers a person's chance of developing it; prevention is limited to vague lifestyle advice.
NowIn April 2025 a study in Nature exploited a vaccine-eligibility cutoff in Wales as a natural experiment and found that people who received the shingles vaccine were about 20% less likely to be diagnosed with dementia over the following seven years, the strongest causal-leaning evidence yet that a widely used vaccine is associated with lower dementia risk.
TaughtObesity is one thing: a BMI of 30 or above. You either cross that line or you don't, and crossing it means you have the disease of obesity.
NowIn January 2025 a Lancet Diabetes & Endocrinology Commission of 58 experts split the concept in two ('clinical obesity,' an actual disease with organ dysfunction caused by excess body fat, and 'preclinical obesity,' excess fat with raised future risk but no current illness) and moved diagnosis beyond BMI alone.
TaughtInterstellar visitors are vanishingly rare. We have seen exactly two objects confirmed to come from beyond our solar system: 'Oumuamua in 2017 and comet Borisov in 2019. Catching a third is a someday hope.
NowOn 1 July 2025 the NASA-funded ATLAS survey spotted 3I/ATLAS, the third confirmed interstellar object, a comet on a wildly hyperbolic orbit that could only have come from another star system.
Pompeii was buried and abandoned in 79 CE
Changed in2025TaughtMount Vesuvius buried Pompeii in 79 CE, killing its inhabitants and sealing the city under ash. It lay empty and forgotten until its rediscovery and excavation in the eighteenth century.
NowExcavations reported in 2025 show people moved back into the ruins after the eruption and lived there for centuries. Survivors and newcomers built dwellings among the buried upper storeys, with coins, ceramics, ovens, and oil lamps documenting occupation from the late first century into the fifth.
TaughtFD&C Red No. 3 (erythrosine) is a federally approved color additive, used for decades in candy, drinks, and medicines. It is on the shelf, so it must be considered safe to eat.
NowOn 15 January 2025 the FDA revoked the authorization for Red No. 3 in food and ingested drugs, ordering it removed from the food supply. The dye had already been banned from cosmetics in 1990; the food ban closes a 35-year gap.
Saturn has 82 moons
Changed in2025TaughtSaturn is the moon champion of the solar system with 82 moons, having narrowly overtaken Jupiter. That is the tidy, memorizable number for the ringed planet's family.
NowIn March 2025 the International Astronomical Union recognized 128 newly confirmed moons of Saturn in one stroke, bringing its total to 274, more than every other planet in the solar system combined.
TaughtThe brain is the body's most protected organ, sealed off by the blood-brain barrier, a tight lining that evolution spent half a billion years perfecting to keep foreign material out. Environmental particles like microplastics circulate in the body but do not reach the brain.
NowA February 2025 study in Nature Medicine found that human brains contain roughly a plastic spoon's worth of micro- and nanoplastics, far more than the liver or kidneys, and that the amount rose about 50% between 2016 and 2024. The barrier is not the seal it was assumed to be.
The body of water south of the US is the Gulf of Mexico
Changed in2025TaughtThe large body of water bordered by the United States, Mexico, and Cuba is the Gulf of Mexico, a name it has held on maps for over four centuries.
NowIn 2025, a US executive order renamed it the 'Gulf of America' for federal use, and the US Geographic Names Information System updated the name on 10 February 2025. The change is binding only inside the US government, Mexico and most of the world still call it the Gulf of Mexico, and there is no international authority that can settle it.
TaughtOur galaxy and the Andromeda galaxy are falling toward each other and will smash together in roughly 4.5 billion years, merging into a single giant elliptical galaxy sometimes nicknamed 'Milkomeda.' It is a certainty, just a distant one.
NowA June 2025 study in Nature Astronomy ran 100,000 simulations with the latest Gaia and Hubble data and found only about a 50-50 chance the two galaxies collide within the next 10 billion years. The head-on merger is no longer a sure thing.
The tokamak is the only serious path to fusion; the stellarator is a scientific curiosity
Changed in2025TaughtMagnetic-confinement fusion means the tokamak, the doughnut design that holds every record. The stellarator, with its baroque twisted magnets, is an elegant idea that never kept up. It is a research sideline, not a contender.
NowOn 22 May 2025 the Wendelstein 7-X stellarator held the fusion 'triple product' (the combination of density, temperature and confinement time that gauges how close you are to a power plant) at a record level for 43 seconds, outperforming what any tokamak had sustained for that long.
TaughtThere is no HIV vaccine and no long-lasting way to prevent infection. Prevention comes down to condoms or, more recently, a pill taken every single day without fail.
NowIn June 2025 the FDA approved lenacapavir (Yeztugo), an injection given just twice a year that prevented HIV in essentially everyone who received it in trials, close to 100% effective.
We have no idea what a Denisovan looked like
Changed in2025TaughtDenisovans are an extinct human cousin known almost entirely from a finger bone, a few teeth, and the DNA inside them. There is no skull, and no real idea what their faces looked like.
NowIn June 2025, molecular analysis identified the near-complete "Dragon Man" skull from Harbin, China as Denisovan, the first Denisovan skull ever recognized and the first genuine look at their face.
We have no idea what a Denisovan looked like
Changed in2025TaughtDenisovans are an extinct human relative known only from a few teeth and a finger bone from a Siberian cave. We have their DNA but no skull, so we don't know what they looked like.
NowIn 2025, molecular analysis identified the near-complete 'Dragon Man' skull from Harbin, China, as Denisovan, giving the group its first face. Ancient proteins and DNA from the skull's tooth plaque tied the massive, heavy-browed cranium, at least 146,000 years old, to the Denisovan lineage.
TaughtMedicines work by binding a target protein and blocking it, like a key jammed in a lock. The drug has to stay bound to keep working, and proteins the body considers 'undruggable', with no good pocket to grab, are simply out of reach.
NowOn 1 May 2026 the FDA approved vepdegestrant (Veppanu), the first PROTAC ever authorized anywhere. Instead of blocking its target, it tags the protein for the cell's own disposal machinery, so the protein is destroyed rather than merely occupied.
TaughtThe CRISPR therapy Casgevy that can functionally cure sickle cell disease was approved for people twelve and older. Young children, who suffer the most damage from the disease early on, were left waiting on the sidelines.
NowOn 1 July 2026 the FDA expanded Casgevy (exagamglogene autotemcel) to children as young as two with severe sickle cell disease or transfusion-dependent beta thalassemia: the first one-time genetic therapy approved for that age group, adding roughly 5,500 eligible children in the US.
Cerebral folate deficiency has no treatment
Changed in2026TaughtWhen a genetic fault blocks folate from reaching the brain, children develop seizures, movement disorders, and severe developmental delay. It is a devastating, untreatable condition; you manage the symptoms and little else.
NowOn 10 March 2026 the FDA approved Wellcovorin (leucovorin calcium) as the first treatment for cerebral folate transport deficiency caused by variants in the FOLR1 gene. Leucovorin is a form of folate that can slip into the brain by a different route, bypassing the broken transporter.
TaughtWhen a child is born deaf because of a genetic defect, the ear is broken at the source. A cochlear implant can route sound around the damage, but there is no way to fix the underlying biology and give the ear its own hearing back.
NowOn 23 April 2026 the FDA approved Otarmeni (lunsotogene parvec), a one-time gene therapy for deafness caused by variants in the OTOF gene. It delivers a working copy of the gene to the inner ear, and most treated patients gained usable hearing, some reaching normal levels, including whispers.
TaughtArginase 1 deficiency lets the amino acid arginine build to toxic levels, causing stiffness, seizures, and developmental regression. There is no drug for it. Management means a severely protein-restricted diet, for life, and it is rarely enough.
NowOn 23 February 2026 the FDA granted accelerated approval to Loargys (pegzilarginase), an engineered enzyme injected to break down the excess arginine the body cannot clear on its own, the first therapy that directly targets the disease.
For early bladder cancer, BCG is the only option, and nothing has improved on it in decades
Changed in2026TaughtHigh-risk bladder cancer that hasn't invaded the muscle is treated by putting BCG, a tuberculosis vaccine, into the bladder. It has been the standard since the 1970s, and despite the cancer often coming back, nothing has been added to it in a generation.
NowOn 28 May 2026 the FDA approved durvalumab (Imfinzi) in combination with BCG for high-risk, non-muscle-invasive bladder cancer: the first immunotherapy combination for the disease, and the first genuinely new approach layered onto BCG in decades.
TaughtThree hundred million years ago, dragonfly-like insects grew to the size of hawks. The standard explanation: atmospheric oxygen was around 45% higher than today, and because insects breathe through passive tubes rather than lungs, only that oxygen-rich air could supply a body that large. When oxygen fell, giant insects became impossible.
NowA 2026 study in Nature found that the insect breathing system is nowhere near its oxygen-delivery limit, so oxygen alone cannot explain the giants. The prevailing high-oxygen theory of insect gigantism doesn't hold up.
TaughtFinding a new asteroid, or catching a supernova as it flares, is painstaking work: an astronomer comparing images, spotting a moving dot or a new point of light, confirming it night by night. Discoveries come in ones and tens, and the vast majority of the sky's changes pass unseen.
NowOn 30 June 2026, the NSF–DOE Vera C. Rubin Observatory began its 10-year Legacy Survey of Space and Time, imaging the entire southern sky every few nights. In just six weeks of early optimization runs it had already found over 11,000 new asteroids, and in full operation it issues up to about 7 million alerts of changes in the sky every single night.
No human has traveled beyond Earth orbit since 1972, and none will for the foreseeable future
Changed in2026TaughtThe last people to leave low-Earth orbit were the Apollo 17 astronauts in December 1972. Ever since, human spaceflight has been stuck circling a few hundred kilometres up (the Space Shuttle, the ISS) and returning to deep space felt perpetually a decade away.
NowOn 1 April 2026, NASA's Artemis II launched four astronauts on a flight around the Moon, the first crewed mission beyond low-Earth orbit since Apollo 17. They looped around the far side and splashed down safely on 10 April, traveling farther from Earth than any humans in history.
Nothing can reach the brain damage of Hunter syndrome
Changed in2026TaughtIn Hunter syndrome, a missing enzyme lets sugary molecules pile up in cells throughout the body and the brain. Enzyme replacement can help the body, but the replacement enzyme cannot cross the blood-brain barrier, so the cognitive decline is untouchable.
NowOn 25 March 2026 the FDA approved Avlayah (tividenofusp alfa), an enzyme replacement engineered to cross the blood-brain barrier: the first treatment for Hunter syndrome aimed at its neurological damage, and the first FDA approval for the disease in nearly twenty years.
The charred Herculaneum scrolls can never be read
Changed in2026TaughtThe library of carbonized papyrus scrolls from Herculaneum, charred solid by the same eruption that buried Pompeii, is unreadable. Unrolling them destroys them, so their contents are lost forever, a whole ancient library we can see but never open.
NowThey can be read without being opened. Using high-resolution CT scans and machine learning, the Vesuvius Challenge recovered the first words in 2023 and full passages in 2024, and in 2026 an entire scroll, PHerc. 1667, was virtually unwrapped and read end to end for the first time.
TaughtThe blockbuster weight-loss and diabetes drugs (semaglutide, tirzepatide) are peptides, fragile protein-like chains your stomach digests. That is why they come as weekly injections. You cannot simply put them in a swallowable, mass-produced tablet.
NowOn 1 April 2026 the FDA approved Foundayo (orforglipron), the first small-molecule GLP-1 receptor agonist: a once-daily pill you can take any time of day, with no food or water restrictions, and that can be manufactured at pharmaceutical scale like an ordinary tablet.
TaughtThe biologics that clear moderate-to-severe psoriasis are large antibody proteins. Swallow one and your gut digests it like food, so they only work as injections. A pill that targets the same pathway is not chemically possible.
NowOn 18 March 2026 the FDA approved Icotyde (icotrokinra), the first oral IL-23 pathway drug for plaque psoriasis. It is a small engineered peptide designed to survive the gut and block the same target the injected biologics hit.
TaughtHigh blood pressure is treated with the same handful of drug families your parents took: diuretics, ACE inhibitors, ARBs, calcium-channel blockers, beta-blockers. Nothing mechanistically new has arrived in decades, and for resistant patients the cupboard is bare.
NowOn 18 May 2026 the FDA approved baxdrostat (Baxfendy), an aldosterone synthase inhibitor, the first mechanistically new class of blood-pressure drug in decades. It blocks the enzyme that makes aldosterone, a hormone that drives hard-to-treat hypertension.
TaughtFocal segmental glomerulosclerosis scars the kidney's filters and marches toward dialysis or a transplant. There is no drug approved specifically for it; doctors borrow steroids and blood-pressure medicines off-label and hope.
NowOn 13 April 2026 the FDA gave full approval to sparsentan (Filspari) as the first medicine ever approved specifically to treat FSGS, based on the phase 3 DUPLEX trial showing it reduced the protein leakage that drives the disease.
TaughtTriple-negative breast cancer lacks the three receptors that targeted drugs aim at, which is what 'triple-negative' means. With no target to hit, treatment falls back on general chemotherapy, and outcomes are poor.
NowOn 22 May 2026 the FDA approved Datroway (datopotamab deruxtecan), the first targeted therapy to beat chemotherapy on survival in first-line metastatic triple-negative breast cancer. It homes in on a protein called TROP2 and delivers a chemotherapy payload directly to the tumor cells.
That’s 34 revisions since 2025.
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