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Stillcant t1_ix9gl6g wrote

Reply to comment by seamustheseagull in Just how dark is deep space? by ArmchairSpinDoctor

You can see well enough to walk around by starlight on earth. It has been a long time since I was that far out, with only a small town 50 miles away, and no cities for hundreds of miles. but I remember being able to read very large text by moonlight , and to walk by starlight. Can’t remember if I could see my hands or what, but there is definitely far far more light than in a cave

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propaganda_bot-9733 t1_ix9neu6 wrote

https://en.wikipedia.org/wiki/Orders_of_magnitude_(illuminance)

Here are the numbers. I can verify that you can hike rough terrain and read large lettering by Moonlight. This was especially true in the winter with leaves off the trees and snow on the ground reflecting the light. But I did not find this to be the case for starlight but it was most definitely not pitch black like a cave. So I hesitantly agree with you.

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TonyToews t1_ixcauy2 wrote

Note that it is possible for retinas to be able to see different levels of dim light. I have no proof of that so I am just guessing. I have an extremely rare retina disease, and it is very difficult for me to see things at night. And now during the daylight as the disease progresses.

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seamustheseagull t1_ixa9mf5 wrote

Afaik, the light on a moonless night is mostly red and green light refracted across the atmosphere from the sun on the other side of the planet.

I've seen some charts suggesting starlight could be strong enough in isolation to illuminate, but it's still drowned out by the relatively bright sunen when it's behind the planet.

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entropy2057 t1_ixbqpdh wrote

>hlight. Not a chance. I flicked a lighter's sparker to flash a momentary light. Another one was riding a bicycle in a VERY dark spot in New Zealand wi

Your comment interested me so I did some googling. Looks like light doesn't actually refract all the way around the earth but the air of the atmosphere actually emits light through various physical processes (airglow). Zodiacal light is also a significant contribution.

https://en.wikipedia.org/wiki/Sky_brightness

The above article is about the apparent brightness of the sky itself and puts starlight at ~7% of the total contribution

The link below directly addresses illumination on the ground and puts starlight at about 1/5th of the total contribution. So away from the atmosphere it would be a lot dimmer for sure but still brighter than a cave~

https://www.cbc.ca/radio/quirks/what-are-the-relative-sources-of-light-on-a-moonless-night-1.6188393#:

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Ooh-Rah t1_ixa9unf wrote

I've been out on the ocean at night, and it's the same thing. I couldn't exactly read by starlight, but I could see enough to not trip over things.

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_AlreadyTaken_ t1_ixb20tk wrote

Once your eyes are fully adjusted a full moon is surprisingly bright. I've turned off my headlight and hiked by moonlight.

In deep space though the light reflected off an object would suffer from the inverse square rule so this faint light would quickly dissapear into the background.

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JohnPombrio t1_ix9xiv6 wrote

Rainy night deep into the woods in the Adirondacks and I needed to follow trail markers with no flashlight. Not a chance. I flicked a lighter's sparker to flash a momentary light. Another one was riding a bicycle in a VERY dark spot in New Zealand without a light. I would ride until my wheel hit gravel, feel for the edge with my shoe, then continue to follow the road until I ran into something.

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Blazin_Rathalos t1_ixaj0pz wrote

> rainy night

I would think that makes a big difference. Your not going to get a lot of starlight when it's overcast.

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account_not_valid t1_ixcdgwn wrote

I've been out in the Australian desert on a moonless night. I could easily walk around and see where I was going.

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