> Hi Carol,
> you wrote: (bold and underlined are mine)
> I'd just like to point out an error in that
> sentence, Vanya. When looking out to see from a
> beach, the horizon is not curved, it's perfectly
> level. That's because each of us is standing in
> the centre of our own 360 circle, looking out
> at a horizon that's equidistant in all
> Thanks for your precisation but I have to say
> that I did not precise other particulars which
> after your puntualization
> are obbligatorily due, in order to better
> understand and of course to not allow other
> erroneus interpretation......
> The locality of the beach I refer, is located
> just before the 3 Greek Kalkidiki penisulas and it
> is 70 km far from Thessaloníki.
> The beach has a little commercial port on its
> left, from where beach started, and after the port
> you can see
> , alwais at your left, the wide bay which at its
> end is visible the west cosat of Cassandra
> penisula till its extreme promontory which is
> situated at about the half lenght of the
> In fromt of the beach and very far away, is the
> East-South coast of Greece which, if there are not
> mist, you
> can see it, along with the important shape of Mont
> On the right side (west - North-west)the beach
> stretches for about 8 kilometer and after that
> start some
> creeks which ended on another promontory distant
> about 30 km.
> So that the sea in bright days without mist, gave
> a vision of 180 degrees and it seems that the sea
> on your left "curved" just after the end of such
> wide bay, giving the same impression od "cuving"
> just after
> the Promontory of Cassandra.
> On your right you have the same impression that
> the sea "curved" after the Promontory I said.
> This impression is given by the shape of the in
> front coast of Greece influenced by the shape of
> Mount Olimpus
> and other Hills and Mountain, and the sea looks
> like "bend down" between the Cassandra promontory
> the Greek coast which is a bit more advanced
> respect that of Cassandra.
> In short word it seems that sea horizont
> line "bend" both on the left and on the right of
> the observer.
> That's why my daughter asked the question of
> curvature..... and of course I could not explain
> to her, due
> to her age (9 year old), a complicate explanation
> which I pointed out above.
> It was just a good occasion to draw her attention
> to the fact that the Earth is a sphere.
> Such kind of "visual phenomenon" can be also sese
> in some part of Liguria's coasts in Italy and as I
> also in Tenerife (one of the Canary Island) in the
> locality called "Los Goigantes".
> I can go ahead with other part of the world I have
> visited but I think that is enough to understand.
> About being in the middle of a huge sea or ocean:
> Only if you are aboard of a Big ship (Cruise or
> Commercial one, does not matter) you can clearly
> see the
> curvature of the horizzont.
> And I have also experienced it.
> More... many years ago I crossed few times, by
> car, the desert route which link Amman to
> I stopped few times just to not seat long hours
> driving (when the road is straight and without
> it is very Dangerous if you do not stop at least
> evry two hours).
> Well then, looking to the horizont, believe me or
> not, I saw the horizont curvature....
> So the phenomenon of perspectives play a
> huge role in each person strictly depending
> from the
> characteristics of the landscape.
> That's why "Flate Earth's believers" are based
> only by the vision of their eyes, like it was for
> people" millennia ago.
> So talking about what eyes can see, the visional
> perspectives, along paradolia, are a common
> which affect all human beings.
> I hope to have clarified the question.
I think we might be referring to two slightly different things here. If you're out at sea, let's say, in a boat surrounded by nothing but ocean, then knowing that you're in the centre of a circle, you can turn 360 degrees and follow the line of the horizon as it encloses you. That's a given. And you've mentioned the mountains you could see around you. Yes, they're so far away that you don't see the entire mountain - its base is obscured by the curve of the horizon. I understand what you're saying there.
But, that's not what I was talking about. What I was referring to was how level the horizon is, distinct from the fact that it curving around you to enclose you in a circle. (Maybe I should have used the term 'level' rather than flat).
What I mean is this: the horizon doesn't form an upward arc from right to left as you look at it - it couldn't, given what it is - a circle cut through a sphere. A circle is level, it doesn't wave up and down. You're at the centre of the circle, and so close to the ground, (if you're 6ft tall or less) that any curvature is far too small to see, only 0.04 degrees. Your horizon at sea level is only 4.5 kms away, far too close to be able to look 'down' on a curve of only 0.04 degrees. You have to take scale into account. An individual human being is microscopic in comparison to the 25,000 mile circumference of the earth. At that scale, earth looks flat.
If you could imagine yourself at the 'tip' of this cone, you could look 'down' on the curve, but that's not what we see from sea level.
The higher you get, the more of the curve you see, but given the huge size of the earth, you can't see the curve from sea level.
This illustration might help to understand what I was saying about scale.
Hope this helps to clarify what I was talking about.
Edited 1 time(s). Last edit at 23-Mar-18 22:33 by carolb.