Editing Sunlight (section)

==Intensity in the Solar System==
[[File:Mars sunset PIA00920.jpg|thumb|right|Sunlight on Mars is dimmer than on Earth. This photo of a Martian sunset was imaged by ''[[Mars Pathfinder]]''. <!-- To compensate for lower levels of sunlight, researchers often enhance images taken on the planet. -- rubbish? -->]]
Different bodies of the [[Solar System]] receive light of an intensity inversely proportional to the square of their distance from the Sun.

A table comparing the amount of solar radiation received by each planet in the Solar System at the top of its atmosphere:<ref>{{cite web|archive-url=https://web.archive.org/web/20091122194548/http://starhop.com/library/pdf/studyguide/high/SolInt-19.pdf|archive-date=2009-11-22|url=http://starhop.com/library/pdf/studyguide/high/SolInt-19.pdf|url-status=dead|title=Solar Intensity|publisher=McAuliffe-Shepard Discovery Center}}</ref>
{| class="wikitable"
|-
! rowspan=2 |[[Planet]] or [[dwarf planet]]
! colspan=2 |distance ([[Astronomical unit|AU]])
! colspan=2 |Solar radiation (W/m<sup>2</sup>)
|-
|[[Perihelion]]||[[Aphelion]]
|maximum||minimum
|-
| [[Mercury (planet)|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
|-
| [[Pluto]]||29.66||48.87||      1.55||      0.57
|}

The actual brightness of sunlight that would be observed at the surface also depends on the presence and composition of an [[atmosphere]]. For example, [[Atmosphere of Venus|Venus's thick atmosphere]] reflects more than 60% of the solar light it receives. The actual illumination of the surface is about 14,000&nbsp;lux, comparable to that on Earth "in the daytime with overcast clouds".<ref>{{cite journal |title=The Unveiling of Venus: Hot and Stifling |journal=Science News |volume=109 |issue=25 |pages=388–389 |date=1976-06-19 |quote=100 watts per square meter ... 14,000 lux ... corresponds to ... daytime with overcast clouds |jstor=3960800 |doi=10.2307/3960800}}</ref>

Sunlight on Mars would be more or less like daylight on Earth during a slightly overcast day, 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. The spectrum on the surface is slightly redder than that on Earth, due to scattering by reddish dust in the Martian atmosphere.

For comparison, sunlight on Saturn is slightly brighter than Earth sunlight at the average sunset or sunrise. 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 Earth, a distance of about 500&nbsp;AU (~69&nbsp;[[light-hour]]s) is needed; only a handful of objects in the Solar System have been discovered that are known to orbit farther than such a distance, among them [[90377 Sedna]] and {{mpl|(87269) 2000 OO|67}}.