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Every ordinary day hides a strange fact.

The Curiosity Index sends one real, sourced science fact to your inbox each morning — the kind you'll repeat at dinner. Physics, biology, chemistry, space, earth science: one field, one fact, every day.

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EVAPORATION CONDENSATION PRECIPITATION COLLECTION
Fact of the day
37,000°C

the surface temperature of a single lightning bolt

That's roughly six times hotter than the surface of the sun — for about a tenth of a millisecond, then it's gone.

Source: NOAA National Severe Storms Laboratory · verified 2026

A small cabinet of things that are actually true

Six facts, six fields. Every one of these sounds made up. None of them are.

Quick trivia
Which planet in our solar system has the shortest year?
Mercury — it completes one orbit of the Sun in just 88 Earth days.

Curiosity, delivered before coffee.

One fact a day, checked against a real source, with a link if you want to go deeper. No noise, no clickbait, nothing to unlearn later.