Please explain this video, UV rays on the Moon

Hi

I´ve found this video and I can´t explain why the astronauts seem to not care about UV rays, in fact, it is the people in Houston that remind this Apollo 17 astronaut to PUT HIS GOLD VISOR DOWN, and he responds I MIGHT????

how is this possible???.

'Snow blindness (Niphablepsia) is a painful condition, typically a keratitis, caused by exposure of unprotected eyes to the ultraviolet (UV) rays in bright sunlight reflected from snow or ice. This is especially a problem in polar regions and at high altitudes, as with every thousand feet (approximately 305 meters) increase in elevation, the intensity of UV rays goes up five percent.
The problem is also related to the condition arc eye sometimes experienced by welders.
Snow blindness is akin to a sunburn of the cornea and conjunctiva, and may not be noticed for several hours from exposure. Symptoms can run the gamut from eyes being bloodshot and teary to increased pain, feeling gritty and swelling shut. In very severe cases, snow blindness can cause permanent vision loss.'- wikipedia

Mattingly was sure the "disappearance" of the stars was due to his **gold visor**. The doctors had advised him to leave the reflector down, LEST HE BE EXPOSED TO HARMFUL RADIATION, but he couldn't stand it anymore."

" *He blinked the visor open just long enough* for the universe to show a familiar face: There they are! "
A Man On The Moon - P.492 A.Chaikin

From Dr Phil Plaits very own review of Deep Impact at BadAstronomy dot com.
"Bad: One of the away team astronauts is ***blinded by the sunlight***.
Good: ***I suspect this may not be totally inaccurate;*** I am not sure how close The Comet was to the Sun when this happened. I would expect NASA to give them sun visors, however, or build in a UV block to the visor. They were on the dark side of The Comet, after all, so they would not have had their sun visors down, and he was admittedly too panicked to think of snapping it down. Still, a moment's exposure should not have so badly burned his face. That was added for drama."

Tribute to Apollo 17's Jack 'Crazy Horse' Schmitt who wasn't the slightest bit concerned about potenial damage to his eyes or burns to his face because he wasn't on the Moon.

[edit on 7-7-2008 by Camilo1]

Originally posted by Camilo1
Hi

I´ve found this video and I can´t explain why the astronauts seem to not care about UV rays, in fact, it is the people in Houston that remind this Apollo 17 astronaut to PUT HIS GOLD VISOR DOWN, and he responds I MIGHT????

how is this possible???.

Back in the apollo days astronauts were somewhat cavalier about their health while the medical team was downright anal. One minor problem on a medical checkup resulted in an astronaut getting bumped from his flight spot, so I'm sure it gave them some pleasure to bend or disregard the physician's orders once they were on the moon and there was nothing the physician could really do to them - Lovell did the same thing by removing his biomedical sensors on apollo 13 - dramatically embellished in the movie version. The astronauts were not in danger of immediate blindness, even your own sources show that.

reply to post by ngchunter


I thank you for your explanation I don`t have the scientific knowledge to refute, what you say is possible but not plausible.

Here is one story of a climber, one of many that I have heard:

The weather, meanwhile, was so good I got brutally sunburned on our very first climb — Nevada Pisco. My face became a painful, festering scab that would not heal for the duration. Descending from our next mountain (Huascaran), I neglected to wear sunglasses for a short time and went snowblind. Crippled with more pain and double vision, I stumbled around for days, unable to climb.

www.climbing.com...



[edit on 7-7-2008 by Camilo1]

additionally - the clear polycarbonate visor gave a degree of protection from UV radiation

Originally posted by Camilo1
reply to post by ngchunter

 

I thank you for your explanation I don`t have the scientific knowledge to refute, what you say is possible but not plausible.

Here is one story of a climber, one of many that I have heard:

Actually it's quite plausible; climbing stories are not comparable to extravehicular activities for a number of reasons. For one thing, Apollo EVAs lasted about 7 hours a piece at most, not all day like a climb, and for at least part of that time Schmitt WAS keeping his visor down. For your claim that he should have been extremely sunburned to be plausible, you'd need to show that such sunburns occur nearly instantenously with only sporadic exposure to UV light.

Lastly, the albedo of snow is much higher than that of lunar soil. Fresh snow, like the kind encountered on the top of a mountain, has an albedo of around 70-85% while the lunar surface has an albedo of only about 12%. That means the amount of UV rays you receive from the reflection off of snow will be MUCH higher than the amount from the reflection off the moon's surface.

Originally posted by ngchunter
Actually it's quite plausible; climbing stories are not comparable to extravehicular activities for a number of reasons. For one thing, Apollo EVAs lasted about 7 hours a piece at most, not all day like a climb, and for at least part of that time Schmitt WAS keeping his visor down. For your claim that he should have been extremely sunburned to be plausible, you'd need to show that such sunburns occur nearly instantenously with only sporadic exposure to UV light.

Lastly, the albedo of snow is much higher than that of lunar soil. Fresh snow, like the kind encountered on the top of a mountain, has an albedo of around 70-85% while the lunar surface has an albedo of only about 12%. That means the amount of UV rays you receive from the reflection off of snow will be MUCH higher than the amount from the reflection off the moon's surface.

Greetings. As a former climber, I would like to comment on this:
a) snow blindness and severe sunburns in the mountains are very real unless protection is used. Even in the fog, there is plenty of UV going around. I lost my tube of sunblock somewhere on McKinley and it took about half a day to thoroughly cook my nose. Ouch.
b) even though the albedo on the Moon is lower, there is no benefit of residual atmosphere that still exists on the mountains -- roughly a half at the altitudes of 15,000 ft and roughly a third on Mt. Everest. You should factor this into your formula.

Then again, I am not sure what we are discussing -- the astronauts may have gotten some sunburns, or may not. Quite plausible. By the way it would depend on which way the person looked -- there is little scattered UV light (again due to missing atmo), and if he was not staring at the Sun (which I doubt he did), he might have gotten away with it.

reply to post by buddhasystem


and i repeat :

go climbing wearing the std apollo EVA helmet - it gives quite a high protection factor

Originally posted by ignorant_ape
go climbing wearing the std apollo EVA helmet - it gives quite a high protection factor

It doesn't have an internal harness to protect against impact, and is likely quite heavy. A light set of good sunglasses and a nice climbing helmet will do, thank you

Originally posted by buddhasystem
Greetings. As a former climber, I would like to comment on this:
a) snow blindness and severe sunburns in the mountains are very real unless protection is used. Even in the fog, there is plenty of UV going around. I lost my tube of sunblock somewhere on McKinley and it took about half a day to thoroughly cook my nose. Ouch.

Again, the astronauts were only out there for 7 hours at a time at most, and had their visor down for some of that time as well. That is not comparable to lacking all forms of protection for the entire duration. I am not debating the existence of snow blindness, I am debating whether the astronauts were at risk for it by keeping their visors up occasionally.

b) even though the albedo on the Moon is lower, there is no benefit of residual atmosphere that still exists on the mountains -- roughly a half at the altitudes of 15,000 ft and roughly a third on Mt. Everest. You should factor this into your formula.

Lunar albedo actually drops off sharply at shorter UV wavelengths so I was actually being quite generous. Lunar albedo at the wavelengths most likely to give you a good burn is actually about .7% (just past UVB) and .3% for far UVC. The atmosphere blocks about 98% of UVB, so the moon actually reflects a lot less UVB back at the astronauts than our atmosphere lets through. I think the actual number of transmissivity for the earth's atmosphere at UVB is somewhere around 1.3%, but you can correct me if I'm wrong cause this is just off the top of my head. That would mean that astronauts would be only dealing with an effective earth surface albedo of 50%, much lower than snow's usual 70-85%. This is not to say it's a wise idea to leave your visor up for all 7 hours, just that you will not be burned by it for leaving it up occasionally.

[edit on 8-7-2008 by ngchunter]