Dear All,
It is well known by physics and human eye biology that on a clear day for a 6 feet (1.82m) average observer eye height from sea level the horizon line distance from the observer is not more than 3 miles or about 5 Km on a calm sea. (Atmospheric light refraction has an minimum effect on the above numbers).
Earth corvarture calculator:
https://dizzib.github.io/earth/curve-calc/?d0=48.28032000002595&h0=1.8288222384784198&unit=metric
(notice an object target distance from the observer of 30 miles (48Km was chosen)
Furthermore, visible horizon line distance is reduced by factors like visibility due atmospheric conditions, sea swelling, atmospheric reflections of sea surface etc.
Therefore visible horizon for an observer due to biological eye perception limitations and physical conditions always precedes true horizon due Earth's curvature and therefore Earth's curvature can not be accounted for or be regarded as responsible for the 2000 years old classical argument that ships bottom first disappear from the horizon due Earth's curvature!
Visible horizon line has still the same effect as true horizon due Earth curvature, thus for objects behind visible horizon will still disappear bottom up first (surface of objects closest to visible horizon line). This is a well known fact from eye biology limitations and how our sight works dictated mainly by eye minimum angular resolution thus 0.02° (i.e. we can not see or resolve objects which have a visual angle less than 0.02°, https://en.wikipedia.org/wiki/Naked_eye) .
Thus an object behind the horizon line depending its visible size as it is going further away from the observer and its size shrinks as we approach the limit of 0.02° angular dimensions limit, will gradually disappear from our vision on the horizon bottoms first.
In conclusion, ships are not disappearing bottoms first due Earth's curvature, but due the visible mainly biological perceived horizon line and by human eye limitations. I submit. Any biology eye specialist and doctor can confirm this.
So then if the above is correct and verified by science, why "the ships bottom first disappearing due curvature" fallacy is kept by by modern physics today?
Kind Regards,
Emmanouil Markoulakis
Technological Educational Institute of Crete
Example:
Boats behind the horizon line not visible to the naked eye brought back to vision on their entirety with an optical zoom:
https://www.youtube.com/watch?v=B4R6Fc79n6c&feature=youtu.be
https://www.youtube.com/watch?v=nYMiGyEbjIg&t=35s
Proving therefore that NO objects disappear behind the horizon due Earth's curvature as common believed but mainly due eye perception limitations and visibility conditions as described on the question above.
I'm sorry but are you claiming that the bottom of the ship is not visible because it's further away? How much of a lean must be on the ship for that to be of any significance?
@ Alexander Malm ,
Lean of boat due Earth's curvature causes more or less about 10 feet hidden height at 4 miles distance for an observer height of 6 feet and is not a valid argument if I can bring back to my vision the boat on its entirety (i.e. including its bottom) from that distance using a visual zoom aid.
Unless you are suggesting that the zoom camera or telescope can cut through the Earth's curvature...X-rays maybe?
Your description above implied that the bottom of the boat could not be seen due to limits of optical resolution based on distance- which would have to imply the bottom of the boat was significantly further away.
In response to the optical zoom "evidence", I would say it is quite clear here that the videos you have shared a link to show a mirage effect, as the "bottom" of the ship is a mirror image of the top of the boat.
Does optical resolution explain the disappearance of the helicopter in this test?
https://youtu.be/QVa2UmgdTM4?t=325
update: metubunk calculator link
Earth's Curve Horizon, Bulge, Drop, and Hidden Calculator
https://www.metabunk.org/curve/
@ Alexander Malm ,
Well if you had like accurate calculation, although they never state the observer eye height but judging by the video it can not be more than 3 feet.
Therefore using the metabunk accurate calculator and plugging in the numbers stated in the video thus 6 miles distance and observer eye height at 3 feet, we get 2.29 miles true horizon distance due Earth's curvature and just 7.86 refracted hidden height (accounting also for atmospheric refraction for 6 miles distance).
So the claim on the video of 24 feet hidden height from the 7.86 feet calculated, is too much of a difference. Water swilling obscuring the view, of the water on the lake due waves can not be accounted for such a big difference, also moreover when a telescope is used. Also less observer height as the assumed would not help your argument either. The difference is too large to be real. I have calculated for an 1 feet observer eye height a 12.5 feet hidden height, half of what is reported namely 24 feet!
Therefore I must come to the conclusion for misinformation at best or fraud at worst used in this documentary. No need really to drag Steven into this science soap opera...
Emmanouil Markoulakis
Technological Educational Institute of Crete
Greece
Hi John,
Long time no see.
How it is going?
I will have look.
Thank you.
Emmannouil
John,
I have started watching your material.
Data Vision-Space online presentations L
In science specially physics and astronomy observation plays an important role in order to construct a theory or conclusion. However, these disciplines always assume that observations made by the observer are realistic and don't include perceptual variables and science of human biology of sight.
They always state "an observer sees..." and that's it!
Not taking into account vision perception and brain processing of images has many implications for physical sciences.
I believe you work in this direction is very important for science and must be high regarded.
Congratulations!
Emmanouil
I have no idea why I am dipping my toes in this argument. You write that "Boats behind the horizon line not visible to the naked eye brought back to vision on their entirety with an optical zoom... Proving therefore that NO objects disappear behind the horizon due Earth's curvature as common believed but mainly due eye perception limitations and visibility conditions as described on the question above."
This is bad science. You cannot PROVE that NO OBJECTS do this. Optical zoom may demonstrate that a specific object can be brought back to vision, but in no way can you generalize that to prove that that is always the case.
Visible horizon always precedes true horizon due curvature. This is always true unless you are talking of an Earth without an atmospheric medium in a vacuum and a 20/20 perfect human sight.
To whom does the 'true' horizons 'actually' occur? It occurs in terms of a geometry that have afforded the term 'true'. The 'poor science' actually lies within the terms of the measurement or another words the allocation of the term 'true' to the system of measurement. These consideration play out within 'vision and observation' but they do not play out in the designated environment of measurement and record making. This is not just a philosophical and visual art matter or shouldn't be? Emmanouil is perfectly correct as a scientist to cite this sort of phenomenon and to demand a 'meaningful' explanation. Vision and observation are things that occur to us and not our instrumentation. Our instrumentation was designed to encounter what we designed it to encounter and to record it in that manner. Models built off this 'platform' are going to miss important stuff. The geometry relating to the fundamentals of optics is just part of the 'physical' story of vision and what's involved in us (complex bio systems) making an observation. An observation is embedded within the universe, a record is likely to be partially embedded and deficient?
John,
Thank you for your confirmation.
You are right. It is a constant battle between the visual reality as perceived by human physiology, senses and brain of ours and the physical reality of the environment we are in. The problem lies I believe that many times Science can nor distinguish clearly between these two.
After all special relativity theory is the study of the apparent against the physical reality. However I must say most in favor of the apparent which is translated and presented by SRT as reality!
So what is more correct and matters more for science?
The perceptual reality or the physical environmental reality?
This question is not easy to answer since the latter many times don't gives the answers we are seeking and knowledge and even if it does we must translate it in our perceptual reality in order to understand it.
Also one can not neglect the apparent reality because this may lead him/her t o false conclusions for the physical reality special if you misinterpret the apparent reality as the physical.
This last paragraph above, is actually the case in our example of this question thread here.
For 2000 years people were talking and measuring, about ships going over the curve totally neglecting the visible apparent horizon which always precedes the curve.
Therefore we can with certainty say Horizon has nothing to do with Earth's curve. The first is an human perceptual apparent reality and the second an environmental physical reality.
So in a nutshell ships don't disappear over the curve but at the perceptual horizon of human vision. I submit.
Emmannouil
I believe it is not scientifically sincere and honest, to keep a false argument for so many eons just because it serves our believes even if it's false.
I expect in the future this fallacy to be rectified by scientists and mainstream media and correct this mistake to the public and education in general.
"After all special relativity theory is the study of the apparent against the physical reality. However I must say most in favor of the apparent which is translated and presented by SRT as reality!"
All theories are images!
"So what is more correct and matters more for science?
The perceptual reality or the physical environmental reality?"
The fundamentals that underpin perceptual reality only get there curtesy of the physically real. The issue is does perceptual reality (experiential reality) that requires us to infer, trump the current scientific image of the real?
In my odd little world the only reality is the relationship we form with the real (experiential reality). This is not to say that experiential reality is entirely veridical etc, just that the fundamentals that drive it have evolved over billions of years from exposure to the environment. They weren't 'invented'! This is likely to be more embedded in the universe than our current conceptual understanding driven by the limitations of our 'inventions'.
So this statement applies to science as well?
"Also one can not neglect the apparent reality because this may lead him/her t o false conclusions for the physical reality special if you misinterpret the apparent reality (supplied by instrumentation) as the physical."
So in a nutshell ships don't disappear over the curve but at the perceptual horizon of human vision. I submit.
I agree! The mechanism of how we develop the perceptual horizon leads us into a deeper relationship with the real?
Earth’s curvature is responsible for the horizon and therefore must precede visible horizon. True horizon does not exist in that, as one travels towards the visible horizon, so that horizon moves relative to the distance travelled by the observer. The Earth is an oblate spheroid and so has no ultimate horizon.
A colleague once climbed a hill called Clisham, a 2600 ft high hill in Harris in the Western Isles of Scotland. 60 miles offshore to the west lie the precipitous islands of St Kilda. At sea level he could not see the islands of St Kilda at all. As he ascended the hill, the tops of the islands began to appear. By the time he reached the summit he could see St Kilda in full. The clarity of the atmosphere in western Scotland permits perfect visibility.
. . . which the rain does occasionally, very occasionally! But then there are the midgies!!! Only the midgies don’t live out at sea.
Seriously, if I were to travel 20 miles up the NW coast of the Moray Firth and look across 30 to 40 miles away at the southern coast of the same Firth, I would see the hills and farmland of Moray and Banffshire BUT I would not be able to see the fishing villages along that coast. The curvature of the Earth prevents me from seeing them. In this case sea conditions play no part due to the greater distance i.e. 30 miles not 3.
In the passing, Emmanoueil, I must mention how your ancient Greeks were so clever. After all, Eratosthenes used his knowledge of the earh’s Curvature to calculate the circumference of the Earth. And that over 2000 years ago.
kind regards
George
@ George J. Strachan
Seriously? The fact that you see the mountains at 30 miles distance and not the small boats and villages is due the fact that you are not Superman!
Without the use of any visual aid you can see obviously only the mountains because:
1. their enormous relative height
2. and most imporatnt due their enormous volume, the appear behind the horizon in your vision with an ancular size 100 times more than the little boats and vilages.
You have reached the minimum angular resolution of your eyes thus 0.02° and therefore your sight can nor resolve these smaller objects relative to the mountain face.
Advise:
Considering clear sky and calm sea and in general perfect visibility conditions, use a strong telescope and you will be able to see more part of the mountain's bottom even at 6 feet eye level height from sea level. Thus meaning that the mountain foot was not hidden by the curve of the Earth but actually by the naked eye visible horizon!
As soon as you start using an optical zoom you will able to sea more mountain foot!
I have done this before and can confirm it.
Emmanouil
p.s. Analogy with ancient Greeks is not valid since they did not had telescopes at that time you are refering, if they had be sure they have come to the same conclusion about the visible horizon not having anything to do with the curve.
The highest ground on the south side of the Moray Firth is 1050 ft. I know the hill well as I climbed it a a boy. The villages of Cullen, Portknockie, Findochey and Buckie are definitely not visible to the naked eye. As John Jupe says “when it is not raining”, which it tends to do a lot in Scotland. It is the rain however that gives us such atmospheric clarity. Suggest you have a holiday in the Scottish Highlands - probably before Brexit!!!!!
@ George J. Strachan ,
Can't answer that Sir.
Too many abstract and undefiened variables to it.
However, I ensure you the visible horizon always precedes the Earth's Curve.
Visible horizon is made up by our eyes and not by the curve, I submit.
Emmanouil
Gents you need to consult the visual artists!
What appears in central vision (this is magnified) masks what appears in contextual vision. So some stuff 'disappears'.
This has sod all to do with your scientific concerns with respect to angles and visual horizons.
Wrong paradigm.
The issue for science lies in the detail of the data sets that present within perceptual awareness (phenomenal field)
How is that perceptual awareness involves 2 takes on the real?
Friday night is Pizza night with red wine. Rather too much wine so sorry about the above! What I meant to say was that perceptual structure allows us to 'compose' phenomenal field to assist with comprehension of a scene. So by enlarging central vision we actually 'loose' some data from the area surrounding central vision. This sort of 'activity' may be contributing to the situation. However, we 'build' visual saliency in part by constantly changing fixation and this process would eventually 'in fill' the missing data and we would 'perceive' over time all the available data about the scene. This doesn't fit with the 'persistent' perception that the ship's hull is below the horizon or that the houses at the bottom of the mountain are missing. I have experienced this phenomenon but not studied it. I am aware that the brain deals with extreme situations (atypical) like far distance in a different way to how it compiles our perception of a vase on a near by table top.
Also a strong indication and proof that visible horizon is a visual perception apparent phenomena created by our sight limitations and not doe a physical envirionmental attribute like the curve of the Earth, is that visible horizon always rises at eye level of the observer regardless his elevation from the ground.
If that would not be the case and visible horizon was made up by the curve, it should fall below our eye level as the observer icreases his elevation. But we know this is not the case.
Only for elevations higher than 100 Km we can start to observe the curve of the Earth as reported by astronaughts and the ISS at 435 Km elevation. And even then the curve is not so much. Our planet is enormous!
The curve many times shown by astronoughts and higl altitude balloons in video footage and photography is not the real one since fish-eye lenses are used which introduce distorion.
Also the claim by many air line passengers, that the see the curve of the of the Earth at 33,000 feer altitude is a mere illusion caused by the horizon line distortion curving effect at the x-axis by our limited peripheral sight of our eyes.
Emmanouil
We should also note that the field structure that underpins vision is spherical in that the disorder field into which data from the real environment 'presents' is set out radially from fixation ie. x,y,x vectors. Its also compressed or condensed the further into contextual vision you go.
Vision-Space: Charting condensation across phenomenal field
http://youtu.be/QgnJ3R3pdoA
One of the things I find impossible to verify is whether or not the 3D field of proximity awareness is limited by distance. ie. when we fixate on a local object we can implicitly determine roughly where things are in space all around it but only to a limited distance from fixation or so I think (20-30 meters)! This could just be the limitation of my conscious ability to determine what's going on however and not a limit to the semi-conscious state of awareness that's derived from the system?
Also casting out into the far distance to make a fixation may make it difficult to determine/set up proximity cues (scale is too fine). One thing is for sure (at least to me!) - we deploy the same radial structure, or try to, irrespective of what we are looking at. The 'field' does not change...only what is appearing within it and the spatial relationships between objects and surfaces. A very economical system of perception.
How else would we achieve the phenomenon of vision? Loads of optically structured 'pictures' that we would have comprehend by determining countless perspective and occlusion cues from the 'lines and edges' that don't actually exist - I don't think so! Way too slow.
Vision and audition play into a base perceptual structure that we can supplement with additional capabilities. I see detailed central vision and optical projection type data as a supplement. ie. the 'where' came before the 'what'.
A possible explanation from the Vision-Space experience?
See if this works for you Emmanouil.
As I stated, we expand or magnify what’s occurring in central vision - ‘what’ we are attending to. In the case of the boat on the horizon we will be trying to get as much detail as we can about the distant object.
What occurs to us in central vision is manifested within the implicit data set – the x,y,z dimensions of the radial field. This materialisation process is a bit like a hologram but we modulate the data-potentials. This occurs within the 3D space of the radial field where spatial considerations play out/present through a system of proximity cues (i.e. not depth-cues form a notional picture frame). We contemplate explicit form (of an object) through time (the impression builds) but contextual spatial awareness ‘presents’ on an implicit basis (we are aware but don't actively intervene in the process).
The brain then has some decisions to make as it composes the phenomenon. The data set of the boat is magnified but must remain central and be on the horizon. The brain also knows that the sea should present a consistent horizontal plane extending out ‘in front of’ the boat. The two (central vision and contextual (peripheral) vision don’t match up so it supresses the data presentation of the bottom/hull of the boat allowing the consistent line of the ocean to be perceived.
Both aspects of the percept are displayed.
This type of ‘masking’ and ‘creative accounting’ process occurs in many other visual evaluation tasks (see Vision-space presentations). This is not about perceptual 'limitations', quite the opposite the processes involve sophisticated techniques to enable us to comprehend the two data potentials (explicit and implicit) simultaneously.
The two visual pathways – what & where.
One of the techniques I use to break into my visual percept is to alternate rapidly between one eye being open and then the other. The brain starts to stack one data-set in each eye and as the alternation is rapid it doesn't have the time to be 'creative' with what's going on. So we need to get to a position where the 'illusion' is occurring with both eye's open and then start alternating to see if we then get to perceive the missing data?
John,
Excellent analysis of visual information brain processing.
Emmanouil
I live close to the Bristol channel and this morning we had some sea haze so no chance of verifying things from here on two counts!.
However I performed the observation process above on a distant tanker. What immediately became clear was that when alternating from one eye to the other to separate out the implicit and explicit data-sets, in implicit vision the boat obviously becomes smaller but in correct proportion to the rest of the scene. The distinction we would be looking for would effectively be about the scale of the waterline band around the boat. However verification of small variations in the very far distance is going to impossible I think. That is of course why we increase the size of objects appearing in the explicit data set.....Dogh!
As Emmanouil states, looking through binoculars will simply wipe the perceptual organisation but allow us to see the waterline mark.
All of this is linked in some way to the moon illusion where we perceive the moon to be bigger that the camera will record it to be. Only here there is no sea to deal with so the whole object is simply increased in size.
On holiday in North Wales. Very clear weather and a totally calm sea. The tankers etc are heading for Liverpool docks. Perfect viewing conditions. As far as I can determine I can see no effect at all!
The experiential reports are made to the contrary are made in good faith of course. I think we have to consider is that any sea swell over such distances will not be read as such. It will be averaged out by the brain and considered and perceived incorrectly as a slight rise of the horizon line?
On holiday in North Wales. Very clear weather and a totally calm sea. The tankers etc are heading for Liverpool docks, perfect viewing conditions. As far as I can determine I can see no effect at all!
The experiential reports are made to the contrary are made in good faith of course. I think we have to consider is that any sea swell over such distances will not be read as such. It will be averaged out by the brain and considered and perceived incorrectly as a slight rise of the horizon line?
On holiday in North Wales. Very clear weather and a totally calm sea. The tankers etc., are heading for Liverpool docks, perfect viewing conditions. As far as I can determine I can see no effect at all!
The experiential reportsare made to the contrary are made in good faith of course. I think we have to consider is that any sea swell over such distances will not be readas such. It will be averaged out by the brain and considered and perceived incorrectly as a slight rise of the horizon line?
On holiday in North Wales. Very clear weather and a totally calm sea. The tankers etc., are heading for Liverpool docks, perfect viewing conditions. As far as I can determine I can see no effect at all!
The experiential reports are made to the contrary are made in good faith of course. I think we have to consider is that any sea swell over such distances will not be readas such. It will be averaged out by the brain and considered and perceived incorrectly as a slight rise of the horizon line?
On holiday in North Wales. Very clear weather and a totally calm sea. The tankers etc., are heading for Liverpool docks, perfect viewing conditions. As far as I can determine I can see no effect at all!
The experiential reports are made to the contrary are made in good faith of course. I think we have to consider is that any sea swell over such distances will not be read as such. It will be averaged out by the brain and considered and perceived incorrectly as a slight rise of the horizon line?
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