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SESK: Stuff Everyone Should Know · sesk.info/astro-light-year-distance

About how far is one light-year?

About 9.46 trillion km (5.88 trillion miles).

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  1. About 9.46 trillion km ✔
  2. About 150 million km
  3. About 300,000 km

Why: A light-year is a distance, not a time: how far light goes in a year at 300,000 km/s. 150 million km is one AU, and 300,000 km is one light-second.

Huh, didn't know that: The nearest star beyond the Sun is a bit over 4 light-years away.

The dad joke
A light-year is like a regular year, but with fewer calories.
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References

Answer: About 9.46 trillion km. A light-year is a distance, not a time: how far light goes in a year at 300,000 km/s. 150 million km is one AU, and 300,000 km is one light-second.

  1. NASA Exoplanet Exploration, What is a light-year? science.nasa.gov/exoplanets/what-is-a-light-year
    5.88 trillion miles (9.46 trillion kilometers) per year
    Checked 2026-10-10.

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