Approximately how long does light take to travel from the Sun to Earth?

Approximately how long does light take to travel from the Sun to Earth?

• A. 4 seconds
• B. 8 seconds
• C. 8 minutes
• D. 8 hours

Answer: (C)

Light travels at a finite speed, so there’s a delay between events at the Sun and what we see here on Earth. The Sun–Earth distance is about 1 astronomical unit, roughly 150 million kilometers. Light moves about 300,000 kilometers every second. Time equals distance divided by speed, so 1.5×10^8 km ÷ 3×10^5 km/s ≈ 5×10^2 seconds, which is about 8 minutes and 20 seconds. Therefore, light from the Sun takes roughly eight minutes to reach Earth. That means the Sun we see is about eight minutes old. The other options don’t fit because 4 seconds is far too short for that distance, and 8 hours would require light to travel a vastly longer distance.

Light travels at a finite speed, so there’s a delay between events at the Sun and what we see here on Earth. The Sun–Earth distance is about 1 astronomical unit, roughly 150 million kilometers. Light moves about 300,000 kilometers every second. Time equals distance divided by speed, so 1.5×10^8 km ÷ 3×10^5 km/s ≈ 5×10^2 seconds, which is about 8 minutes and 20 seconds. Therefore, light from the Sun takes roughly eight minutes to reach Earth.

That means the Sun we see is about eight minutes old. The other options don’t fit because 4 seconds is far too short for that distance, and 8 hours would require light to travel a vastly longer distance.