Mystery of Reflected Sunlight 73 Miles Away - A Man's Quest

[Skeptic Tom]

I read in a book about a man who saw the sun reflected off a distant object on a mountain some 73 miles away in clear visibility. He saw this on many occasions and always wondered what it could be. He states that he asked two of his friends who were going that way if they would check it out for him.

Some days later after his friends returned, then said they had no problem finding it. It turned out to be a bottle. I find this hard to believe. Surely the reflection could only be seen at a certain angle and as soon as one strays a short distance out of that angle, the reflected light from the bottle could not be seen? Not only that but by the time those looking for it had traveled a few hours, the angle of the sun would also have changed. So how on Earth could they locate a bottle on a huge mountain? When one gets to that mountain, they would have had a huge area to search. Surely they would have no way of knowing that was the source of reflected light?

The other question is, could the reflected light from a mere bottle travel 73 miles?

 

[blue_leaf77]

I read in a book

What book is it?

 

[pixel]

Surely the reflection could only be seen at a certain angle and as soon as one strays a short distance out of that angle, the reflected light from the bottle could not be seen?

Maybe because the bottle is curved, so can accommodate many different angles of incidence and reflection.

The other question is, could the reflected light from a mere bottle travel 73 miles?

From atop high mountains you can see over 100 miles away. If there is a high-contrast bright spot at that distance, I think it could be noticeable.

 

[anorlunda]

The effectiveness of the signal mirror is what you are having a hard time imagining. For millennia, sailors have used them to get rescued at sea.

Read about iridium flares for reality even harder to believe.https://en.m.wikipedia.org/wiki/Satellite_flare

Better still, view iridium flares yourself. I use the android app Predisat-pro to tell me where and when to look. The app uses data from the heavens above Web site.

 

[anorlunda]

Also see

[/PLAIN]
The record distance was established by a detachment of U.S. signal sergeants by the inter-operation of stations on Mount Ellen, Utah, and Mount Uncompahgre, Colorado, 183 miles (295 km) apart on September 17, 1894, with Signal Corps heliographs carrying mirrors only 8 inches square.

In special lighting circumstances, they can be even better. Especially when you are looking east at sunset, or west at sunrise. If you are in twilight and the mirror is on a mountain peak in sunlight, effectiveness is at its peak.

I am not an expert on vision, but I believe that our vision processing makes brief changes more noticeable than static images. Thus, the ability to resolve tiny static images is not the same as the ability to see flashes.

 

[Skeptic Tom]

What book is it?

Hi Blue Leaf 77, I am almost afraid to say...it is a book called Millennial Hospitality by Charles James Hall who claims to have met aliens while he served as a meteorologist with the US military in the 1960's. He says he is now a Nuclear Physicist. My sceptical nature likes to challenge everything and there are a number of issues in his book that don't add up. This particular question is just one. Tom.

 

[Skeptic Tom]

Maybe because the bottle is curved, so can accommodate many different angles of incidence and reflection.
From atop high mountains you can see over 100 miles away. If there is a high-contrast bright spot at that distance, I think it could be noticeable.

Good point about the curved bottle. Thanks

 

[Skeptic Tom]

Also see
In special lighting circumstances, they can be even better. Especially when you are looking east at sunset, or west at sunrise. If you are in twilight and the mirror is on a mountain peak in sunlight, effectiveness is at its peak.

I am not an expert on vision, but I believe that our vision processing makes brief changes more noticeable than static images. Thus, the ability to resolve tiny static images is not the same as the ability to see flashes.

Thanks, interesting

 

[Skeptic Tom]

The effectiveness of the signal mirror is what you are having a hard time imagining. For millennia, sailors have used them to get rescued at sea.

Read about iridium flares for reality even harder to believe.https://en.m.wikipedia.org/wiki/Satellite_flare

Better still, view iridium flares yourself. I use the android app Predisat-pro to tell me where and when to look. The app uses data from the heavens above Web site.

thanks for that info

 

[Skeptic Tom]

Also see
In special lighting circumstances, they can be even better. Especially when you are looking east at sunset, or west at sunrise. If you are in twilight and the mirror is on a mountain peak in sunlight, effectiveness is at its peak.

I am not an expert on vision, but I believe that our vision processing makes brief changes more noticeable than static images. Thus, the ability to resolve tiny static images is not the same as the ability to see flashes.

Excellent info, thanks

 

[CWatters]

Perhaps his friends just told him it was a bottle so they didn't have to spend ages looking for it.

 

[blue_leaf77]

Human eyes' angular resolution is 0.0003 rad. At 73 miles distance, our eyes cannot distinguish objects within 35 meters. If he was satisfied with his friend's answer that it was just a bottle, he must have forgotten that fact.

 

[Skeptic Tom]

After the 'bottle' was found and removed, there are no further reports of the reflection, so that must have resolved the 'curiosity.' If we are to believe the story, then it was the bottle that was causing the reflection.

I live many thousands of miles away, in Ireland, and there are mountains about 25 miles from me. If I saw a reflection coming from the mountain side and got in my car to find its source, by the time I got to the foot of the mountain, I doubt if I would have a clue where to start looking, so it still seems quite improbable that the reflecting bottle could be found easily and tends to make me skeptical of this part of the bottle story.

 

[sophiecentaur]

Perhaps his friends just told him it was a bottle so they didn't have to spend ages looking for it.

Yes. I would imagine it was not the first time they had to deal with his fanciful notions.
For the reflection to be bright enough in his direction, the beam width would need to have been very small. The probability of one flash from the 'bottle' is, perhaps, finite but the next day or even a minute later, the beam would no longer be aimed at the observer. The distance involved is comparable with the distance of satellites in LEO and we only see them after sunset (with a dark background and little scattered light). There are many bottle-sized facets on satellites so we could expect a constant view of sparkles from passing satellites all day. (There are thousands of the little devils up there.)
Perhaps the explanation is reflection a passing aeroplane at low altitude (coming into land, perhaps) at a nearby airfield. (Forget the bottle)

 

[pixel]

Human eyes' angular resolution is 0.0003 rad. At 73 miles distance, our eyes cannot distinguish objects within 35 meters. If he was satisfied with his friend's answer that it was just a bottle, he must have forgotten that fact.

Calculations of resolution usually deal with two close sources of equal brightness. You also have to take into account contrast. If an object is very bright, it can be noticeable despite having a very small angular extent, such as a star.

 

[blue_leaf77]

Calculations of resolution usually deal with two close sources of equal brightness. You also have to take into account contrast. If an object is very bright, it can be noticeable despite having a very small angular extent, such as a star.

My point is that there can be another shiny object in the vicinity of the bottle that also contributes to the rays that impinge on the observer's eyes, apart from the bottle, without he/she being able to tell them apart. Not to mention that this other object might be much more reflective than a bottle, for example a sheet of metal.