Where does this come from, and can I check it?

It measures distance, not time, and the nearest star is over four away. The figure is taken from Britannica, which is linked in full on this page. Every fact on Mondo Knows names its source rather than repeating an unsourced claim.

Is this really a space fact?

Yes. It sits on the Space shelf, one of 2,600 sourced facts grouped into space, animals, the human body, history, science and more. Category pages collect every fact in the same field.

What else can I read about it?

The links under the fact point to a quiz, game, puzzle or calculator on the same subject, and the shelf below shows related facts. The wording here is original, and quoted phrases are marked as quotations.

Mondo Knows Facts

A light year is 9.461 trillion kilometres

It measures distance, not time, and the nearest star is over four away Light travels 299,792,458 metres a second, so a light year is about 63,241 astronomical units. Proxima Centauri sits 4.25 light years off, the closest star beyond the Sun. The Milky Way spans roughly 100,000 light years. It sits in Mondo's space collection, one of 200 facts that each trace back to the reference below.

Where this comes from

Britannica

Facts that can change over time are reviewed and updated. If something here looks wrong, Mondo would rather know than be confidently incorrect.

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Science trivia

More facts like this

An astronomical unit is 149.6 million kilometresIt began as the Earth-Sun distance and is now a defined constant A parsec is a parallax measurement, not a timeIt is the distance at which Earth's orbit subtends one arcsecond Splitting starlight reveals what a star is made ofEach element leaves dark lines at fixed wavelengths The observable universe contains septillions of starsAstronomers estimate there are more stars in space than sand grains on Earth Proxima Centauri is the closest star to our solar systemThe red dwarf star sits roughly four point two light-years away from Earth Brown dwarfs are failed stars that cannot sustain core nuclear fusionSubstellar objects bridge the evolutionary gap between giant gas planets and stars

Tags: units, stars, distances

A light year is 9.461 trillion kilometres: the short answers

Where does this come from, and can I check it?: It measures distance, not time, and the nearest star is over four away. The figure is taken from Britannica, which is linked in full on this page. Every fact on Mondo Knows names its source rather than repeating an unsourced claim.
Is this really a space fact?: Yes. It sits on the Space shelf, one of 2,600 sourced facts grouped into space, animals, the human body, history, science and more. Category pages collect every fact in the same field.
What else can I read about it?: The links under the fact point to a quiz, game, puzzle or calculator on the same subject, and the shelf below shows related facts. The wording here is original, and quoted phrases are marked as quotations.