• A. About 8 minutes
  • B. About 30 seconds
  • C. About 1 hour
  • D. About 20 minutes

Light travels incredibly fast — around 300,000 kilometres per second. The distance between the Sun and the Earth is approximately 150 million kilometres. Divide one by the other and you’ll get surprisingly close. :::

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The correct answer is A. About 8 minutes.

The average distance between the Sun and the Earth is around 150 million kilometres. Light travels at approximately 300,000 kilometres per second. Dividing that distance by the speed of light gives you roughly 500 seconds — just over 8 minutes. The sunlight you see right now left the Sun more than eight minutes ago.

📚 More background information

This fact makes for a wonderful philosophical tidbit: we always see the Sun as it was eight minutes ago. Look at stars that are much farther away, and you’re gazing years or even centuries back in time, because their light takes far longer to reach us.

The exact travel time varies slightly throughout the year. Earth’s orbit around the Sun is not perfectly circular but slightly elliptical. This means the Earth is sometimes a little closer to the Sun and sometimes a little farther away, causing the light travel time to range between roughly 8 minutes and 8.5 minutes.

The speed of light is often regarded as the cosmic speed limit: nothing can travel faster. This makes distances in the universe so vast that astronomers frequently express them in light-years — the distance light covers in an entire year. A handy fact to keep in your back pocket for the next astronomy round at the pub quiz.