Sunlight on Mars is approximately half as strong as we get it. Add their clouds and dust, it amounts to no more than our twilight.
10 seconds sound clip from the The War of the Worlds (1953) movie soundboard.
You can hear this line at 00:57:12 in the DVD version of the movie.
Quote context
[...]
- I don't remember ever seeing blood crystals as anemic as these.
- They may be mental giants, but by our standards, physically they must be very primitive.
- Isn't it curious how everything about them seems to be in threes?
- Their eyes have three lenses, three distinct pupils.
- They're not accustomed to it.
- Now, if you'll step over here, please.
- We've rigged the epidiascope to reflect whatever the Martian lens picks up.
- Move in a little. Thank you.
- There's how the Martians see us.
- Evidently there's a shift in their spectrum.
[...]