The Sun is roughly 150Â million kilometers (1 Astronomical unit) from the Earth. The Sunlight travels at a speed of about 300,000 kilometers/sec. By using the simple formula, “time= (distance/speed)”, we can calculate the time taken by sunlight to reach Earth.
Time taken by sunlight to reach Earth = (150,000,000/3,00,000) seconds = 500 seconds = 8 minutes 20 seconds
The Sunlight takes 8 minutes and 20 seconds on average to reach Earth.
When Earth is at the perihelion, this time is reduced as Earth is closer to the Sun. At perihelion, the distance between Sun and Earth is about 147 million kilometers and the sunlight takes 490 seconds (8 minutes 10 seconds) to reach Earth.
When Earth is at the Aphelion, the Sunlight takes 507 seconds to reach Earth (8 minutes 27 seconds). At aphelion, the distance between Sun and Earth is about 152 million kilometers.
Time taken by Sunlight to reach different planets
| Planet | Time taken by Sunlight to reach |
| Mercury | 3 minutes 13 seconds |
| Venus | 6 minutes |
| Earth | 8 minutes 20 seconds |
| Mars | 12 minutes 40 seconds |
| Jupiter | 43 minutes 15 seconds |
| Saturn | 1 hour 19 minutes |
| Uranus | 2 hours 40 minutes |
| Neptune | 4.1 hours |
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