21 entries
Earth Science
Reclassified clouds, recounted continents, and a planet that turned out to be more dynamic than the diagram.
Changes here run from 1968 to 2025.
- Updated10
- Disproved7
- Refined2
- Replaced2
- UpdatedNot in textbooks yet
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.
- Updated
The Dragon Hole is the deepest blue hole on Earth
Changed in2024TaughtThe deepest known underwater sinkhole (a 'blue hole') is the Dragon Hole in the South China Sea, plunging about 300 metres. That is the record you would have found in any recent reference.
NowIn 2024, researchers reported that Taam Ja' Blue Hole in Mexico's Chetumal Bay reaches at least 420 metres deep, more than 100 metres deeper than the Dragon Hole, and that the instrument never touched the bottom, so the true depth is greater still.
- Updated
The world has never crossed the 1.5°C warming line
Changed in2024TaughtThe Paris Agreement's 1.5°C limit is a distant guardrail. Global temperatures are rising, but no calendar year has ever averaged more than 1.5°C above pre-industrial levels; that threshold is something to prevent in the decades ahead.
Now2024 was the first calendar year to average more than 1.5°C above the 1850–1900 baseline: about 1.55°C by the WMO's consolidated analysis of six datasets, and the warmest year on record. The line that anchored a generation of climate targets was crossed for a full year for the first time.
- Updated
We have left the Holocene and entered the Anthropocene
Changed in2024TaughtHuman activity has pushed Earth out of the Holocene and into a new geological epoch, the Anthropocene, defined by our impact on the planet. It is the epoch we now live in.
NowIn March 2024 the scientific bodies that name geological time formally rejected the proposal to add the Anthropocene as an epoch. Officially, we are still in the Holocene. "Anthropocene" survives as a useful informal term, not a unit on the geological timescale.
- Updated
Earth's spin axis only wobbles from natural forces
Changed in2023TaughtEarth's rotational axis wanders slightly over time, a natural wobble driven by things like the melting of ancient ice sheets and shifts deep in the planet. It's a geological process, far beyond human influence.
NowA 2023 study found that humans pumping groundwater have measurably shifted Earth's spin axis. Extracting about 2,150 gigatonnes of groundwater between 1993 and 2010, and moving that water to the oceans, tilted the rotational pole roughly 80 cm eastward, about 4.3 cm per year.
- Refined
The Earth has a crust, a mantle, and a core
Changed in2023TaughtCut the Earth in half and you get neat concentric shells: crust, mantle, liquid outer core, solid inner core. Four layers, colored on the diagram.
NowThere is evidence of a distinct innermost inner core, roughly 650 kilometers across, with a different crystal alignment from the rest of the inner core. Published in Nature Communications in February 2023, it makes a fifth layer.
- Updated
TaughtThe Moon's tidal drag steadily brakes Earth's spin, so every century the day grows a couple of milliseconds longer. That is why we occasionally add a 'leap second'; the planet is always, gradually, slowing down.
NowOn 29 June 2022, Earth completed a rotation 1.59 milliseconds short of 24 hours: the shortest day since atomic clocks began measuring, part of a run of record-fast days since 2020. The planet has recently been speeding up, not slowing.
- Disproved
TaughtGlobal warming is a theory. Some scientists think humans are causing it, others think it is a natural cycle, and the debate is ongoing.
NowThe IPCC's Sixth Assessment Report in 2021 states that it is unequivocal that human influence has warmed the atmosphere, ocean, and land. "Unequivocal" is the strongest word the IPCC has ever used on attribution, and it has no qualifier.
- Updated
We can only guess at the minerals deep in the mantle
Changed in2021TaughtThe lower mantle is 660 to 2,900 km down and unreachable. We know its minerals only from laboratory experiments that squeeze samples to those pressures; we have never had an actual piece of one.
NowIn 2021, scientists confirmed a real sample of a lower-mantle mineral for the first time, calcium silicate perovskite, now named davemaoite, found trapped as a flaw inside a diamond from Botswana. It had been predicted for decades but never seen in nature until it hitched a ride to the surface.
- Updated
Magnetic north sits in the Canadian Arctic
Changed in2020TaughtYour compass points to the magnetic north pole, which sits in the Canadian Arctic. It wanders a little, but it's essentially parked up there near Canada's northern islands.
NowThe magnetic north pole has bolted. It left Canada, crossed the international date line, and is heading toward Siberia so fast that the World Magnetic Model, which guides every phone map and ship's compass, had to be updated ahead of schedule in 2020, and again for 2025.
- Disproved
The Amazon produces 20 percent of the world's oxygen
Changed in2019TaughtThe Amazon is the lungs of the planet, producing about a fifth of the oxygen we breathe. Cut it down and we suffocate.
NowThe Amazon's net oxygen contribution is close to zero. It consumes nearly all the oxygen it produces through respiration and decomposition. Most atmospheric oxygen came from marine phytoplankton over billions of years, and the atmospheric reservoir is so vast it would not budge in any case.
- Updated
The ozone hole is growing and there's nothing to be done
Changed in2018TaughtA hole in the ozone layer is opening over Antarctica and expanding. It is one of the defining environmental catastrophes of your lifetime and it is getting worse every year.
NowIt is healing. The 2018 WMO/UNEP Scientific Assessment confirmed ozone recovering at roughly 1 to 3 percent per decade, and projections have the Antarctic hole closing around 2066. The Montreal Protocol worked.
- Disproved
Recycling solves the plastic problem
Changed in2017TaughtSort your plastics by the number in the triangle, put them in the right bin, and they become new products. Recycling is the answer to plastic waste.
NowAbout 9 percent of all plastic ever produced has been recycled. Roughly 12 percent has been incinerated and the rest is in landfills or the environment. Most plastics are not economically recyclable, and the industry knew this while promoting the bins.
- Updated
There are ten types of cloud
Changed in2017TaughtClouds come in ten genera: cirrus, cumulus, stratus, and the rest. Learn the chart on the classroom wall, because it is fixed.
NowThe World Meteorological Organization's International Cloud Atlas added twelve new classifications in March 2017, including asperitas, the first new formation added in over half a century, and volutus, cavum, and the human-made flammagenitus and homogenitus.
- Replaced
Stand in a doorway during an earthquake
Changed in2005TaughtWhen the shaking starts, get into a doorway. The frame is the strongest part of the house and it will hold when the rest comes down.
NowDrop, cover, and hold on. Get under a sturdy table, or against an interior wall covering your head and neck. Doorways in modern buildings are no stronger than any other part of the structure, and standing in one leaves you exposed to falling objects and a swinging door.
- Refined
The Earth is a sphere
Changed in2002TaughtThe Earth is a sphere, like the globe on the teacher's desk.
NowIt is an oblate spheroid, bulging at the equator by about 21 kilometers, and lumpy on top of that. GRACE satellite gravity mapping from 2002 produced the true shape, the geoid, which is irregular enough that its exaggerated rendering is nicknamed the potato.
- Disproved
Open your windows when a tornado approaches
Changed in1998TaughtA tornado's low pressure will make your sealed house explode, so open the windows on the side away from the storm to equalize pressure before you take shelter.
NowDo not open windows. Houses are not airtight, pressure equalizes on its own, and the explosion theory is wrong. Opening windows wastes the seconds you need to get to shelter and lets wind and debris in. Go to the lowest interior room, away from windows.
- Disproved
Diamonds are made from coal under pressure
Changed in1995TaughtSqueeze coal hard enough for long enough and you get a diamond. It is the standard classroom metaphor for pressure making something beautiful.
NowAlmost no natural diamond came from coal. Most formed 150 to 200 kilometers deep in the mantle from carbon that has been there since the planet formed, and most are older than the land plants that coal is made from.
- Disproved
Lightning never strikes the same place twice
Changed in1990TaughtLightning never strikes the same place twice, so a spot that has just been hit is the safest place to stand.
NowLightning strikes favored places repeatedly and by preference. The Empire State Building is hit roughly 20 to 25 times a year. A single flash often contains multiple strokes down the same channel within a fraction of a second, so lightning frequently strikes the same place twice within milliseconds.
- Disproved
Summer happens when Earth is closer to the Sun
Changed in1987TaughtEarth's orbit is an ellipse. When we swing closer to the Sun it is summer, and when we are farthest away it is winter.
NowSeasons come from the 23.4 degree axial tilt, which changes the angle of incoming sunlight and the length of the day. Earth is actually closest to the Sun in early January, during northern winter, and the orbit is nearly circular anyway.
- Replaced
Continental drift is an interesting but unproven theory
Changed in1968TaughtAlfred Wegener noticed the continents fit together like a jigsaw, but he could not explain how they moved, so the idea remains speculative and most geologists reject it.
NowPlate tectonics is the unifying framework of the earth sciences, settled by 1968. GPS now measures plate motion directly, in real time, to millimeter precision. The Atlantic widens about 2.5 centimeters a year, roughly the rate your fingernails grow.