Fermi question · Science
About how many meters per second is the speed of light in a vacuum?
Make a fast, defensible estimate before you reveal the reference answer. Think in factors, not exact recall.
What is your estimate?
Your result will appear here after you submit a guess.
Reference answer
Reveal the reference answer
≈ 300 million meters per second
Fermi estimates are judged by scale, so a reasonable approximation can still earn a strong score.
One way to estimate it
Convert the common 300,000 km/s approximation into meters per second.
- Light speed≈ 300,000 km/s
- Meters per kilometer1,000
- Estimate300,000 × 1,000 ≈ 300M m/s
Keep practicing
Try another question, or return to the daily challenge to build your personal sense of scale.