How this site decides that something changed

The easy version of this site would be a list of things school got wrong. That version would be more fun for about ninety seconds and wrong itself, because most of what you were taught was the best available answer at the time, and most of it did not get overturned. It got sharper.

What earns an entry

Three tests. The claim had to be genuinely taught in mainstream schools rather than merely believed by somebody. The shift had to be documented by a body with standing: a scientific union, a health agency, a peer-reviewed result that carried the field, a dictionary or style guide, a government. And the change has to be datable to a year you can point at, because the whole site turns on comparing that year against yours.

Playground myths that no teacher ever wrote on a board are out. So is anything where the evidence is still moving and the honest answer is “we don’t know yet.” Where a question is genuinely contested, the entry says so rather than pretending the argument is finished.

The six labels

Every entry carries exactly one. This is the part that matters most, and the part most articles like this skip. Calling a refinement a disproof is itself a factual error.

Disproved

The old claim turned out to be wrong and was rejected by evidence.

Updated

The core idea stands, but key numbers or details have changed.

Reclassified

The thing itself didn't change; its official category did.

Renamed

Same thing, new accepted name.

Replaced

An old model or guideline was retired in favor of a new one.

Refined

Not wrong, but our understanding became significantly more precise.

The split is worth stating plainly, because it is not the one you might expect. Of the 259 entries here, 125 are labelled disproved: things taught as fact that the evidence simply demolished. The other 134 are updates, refinements, replacements, renamings, and reclassifications, where the earlier answer was reasonable given what was known.

Roughly half, in other words, and that is a selection effect rather than an indictment of teachers. A claim has to have been taught confidently and then overturned to earn a place here, and myths are unusually good at meeting both conditions: they are memorable, they are repeatable, and nobody checks them. The vast bulk of what school taught you was fine and is therefore not on this site at all.

The year on each entry

Changed is the year the mainstream position moved: the vote, the publication, the guideline revision. It is not the year the news reached every classroom, which is usually years later and impossible to pin down. That gap is real and it cuts in your favor. If your year page says something changed in 1998, your school may well have kept teaching the old version into the 2000s.

A year page for 1950 to 2026 shows every entry whose change year is later than yours. That is the entire rule.

Sources

Every entry cites at least two, and they point at the institution that made the change wherever one exists: NASA, the IAU, the NIH, the WHO, the USDA, national geological and meteorological surveys, the journals that published the result. Where a secondary source is used, it is one with an editorial correction policy.

Corrections

Some of these are wrong. That is not false modesty, it is arithmetic: a site about knowledge being revised does not get to claim exemption. If you can point at a source, the entry gets fixed or pulled. A site that argues textbooks should update and then refuses to is just a textbook.

What we know about you

Nothing. No account, no cookie, no stored answer, not even the year you picked. The privacy page spells out the specifics.