Intensity in The Solar System
Different bodies of the Solar System receive light of an intensity inversely proportional to the square of their distance from Sun. A rough table comparing the amount of solar radiation received by each planet in the Solar System follows (from data in ):
| Planet | Perihelion - Aphelion distance (AU) |
Solar radiation maximum and minimum (W/m²) |
|---|---|---|
| Mercury | 0.3075 – 0.4667 | 14,446 – 6,272 |
| Venus | 0.7184 – 0.7282 | 2,647 – 2,576 |
| Earth | 0.9833 – 1.017 | 1,413 – 1,321 |
| Mars | 1.382 – 1.666 | 715 – 492 |
| Jupiter | 4.950 – 5.458 | 55.8 – 45.9 |
| Saturn | 9.048 – 10.12 | 16.7 – 13.4 |
| Uranus | 18.38 – 20.08 | 4.04 – 3.39 |
| Neptune | 29.77 – 30.44 | 1.54 – 1.47 |
The actual brightness of sunlight that would be observed at the surface depends also on the presence and composition of an atmosphere. For example Venus' thick atmosphere reflects more than 60% of the solar light it receives. The actual illumination of the surface is about 14,000 lux, comparable to that on Earth "in the daytime with overcast clouds".
Sunlight on Mars would be more or less like daylight on Earth wearing sunglasses, and as can be seen in the pictures taken by the rovers, there is enough diffuse sky radiation that shadows would not seem particularly dark. Thus it would give perceptions and "feel" very much like Earth daylight.
For comparison purposes, sunlight on Saturn is slightly brighter than Earth sunlight at the average sunset or sunrise (see daylight for comparison table). Even on Pluto the sunlight would still be bright enough to almost match the average living room. To see sunlight as dim as full moonlight on the Earth, a distance of about 500 AU (~69 light-hours) is needed; there are only a handful of objects in the solar system known to orbit farther than such a distance, among them 90377 Sedna and (87269) 2000 OO67.
Read more about this topic: Sunlight
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