Earth curvature around the UK?

[C08]

My wife, who is normally a perceptive and thoughtful soul is convinced that the horizon appears to have more curvature in the NW of England eg Irish Sea viewed westwards from Wales compared to say the horizon in the south say, the channel viewed southwards from the S coast. I have no views on this but I would be interested if anyone else has the thought that certain places appeared to have more curvature at the horizon than others. Any ideas?

 

[Eyore]

The earth is definitely flat.:encouragement:

 

[mjcoon]

My wife, who is normally a perceptive and thoughtful soul is convinced that the horizon appears to have more curvature in the NW of England eg Irish Sea viewed westwards from Wales compared to say the horizon in the south say, the channel viewed southwards from the S coast. I have no views on this but I would be interested if anyone else has the thought that certain places appeared to have more curvature at the horizon than others. Any ideas?

I take it you are referring to the sea horizon (after all, there is a horizon on land too)...

There is variation, because we know that the world is not an accurate sphere. But the variations can only be tiny, since the water would move to level out according to local gravity. So I cannot believe that any variation will be visible without using very sophisticated surveying equipment (and maybe not even then!).

Mike.

 

[Hoolie]

Technically that's correct - in the UK the curvature to the south will be be infinitesimally less than to the west. I think any perceived difference will be down to atmospheric conditions

 

[LittleSister]

But the variations can only be tiny, since the water would move to level out according to local gravity.

Curiously, the surface of the sea is not flat (nor even spheroid, nor even the oblate(?) sphere of the earth). Ignoring waves and tides, there are still higher and lower parts of the oceans' surface. Can't remember either the explanation (presumably includes currents and variations in gravity). IIRC there are both 'permanent' and seasonal/temporary changes. If you Google search for images of 'ocean surface height variation' you'll see some.

Can't imagine that it explains what the OP's wife is seeing, though.

 

[dratsea]

If you want to humour her then reassure her that as the distance to the horizon depends on height of eye, and the further you see the more the curvature will be apparent. As we all know, in many places N Wales reaches the sea over a cliff but there are more gentle slopes over much of South coast so it is not surprising and very astute of her to note that there is less curvature.

If not:




.





.... suggest she should have gone to Specsavers!

Regards, J

 

[Rigger Mortice]

Tell her to take some photo's from the same elevation at each location. When she compares them she will have her answer.

 

[Robert Wilson]

Perceived curvature of the horizon depends on the thickness of the bottom of the glass from which one is drinking........................

 

[dratsea]

As an aside and in no way reflecting on your good wife:



Did you know the Adam had reservations about donating a rib? However God assured him that from it he would create perceptive and thoughtful souls to be called women and that they would be found on every corner of earth?



Adam accepted the assurances.



And God created Eve,



And all women are in the likeness of Eve.



And the dear Lord always told the truth.



But he forgot to mention that:



He had created the earth round.



J

 

[alant]

As an aside and in no way reflecting on your good wife:



Did you know the Adam had reservations about donating a rib? However God assured him that from it he would create perceptive and thoughtful souls to be called women and that they would be found on every corner of earth?



Adam accepted the assurances.



And God created Eve,



And all women are in the likeness of Eve.



And the dear Lord always told the truth.



But he forgot to mention that:



He had created the earth round.



J

 

[NorthRising]

Perceived curvature of the horizon depends on the thickness of the bottom of the glass from which one is drinking........................

What a brilliant statement! Or perhaps how much one imbibes from the glass.

 

[Moonshining]

My wife, who is normally a perceptive and thoughtful soul is convinced that the horizon appears to have more curvature in the NW of England eg Irish Sea viewed westwards from Wales compared to say the horizon in the south say, the channel viewed southwards from the S coast. I have no views on this but I would be interested if anyone else has the thought that certain places appeared to have more curvature at the horizon than others. Any ideas?

As far as I can work out, the horizon doesn't have a visible curvature at all unless you're in orbit. Any lower and you're seeing a portion of the earth's surface roughly the shape of a contact lens and you can lay the edge, ie the "horizon", of one of those on a flat surface.

 

[johnalison]

The horizon would only be a straight line if your eye level were at the height of the surface instead of some five feet or more above, though whether the curvature is noticeable is a moot point. The only straight line you are likely to see is a vertical straight ahead. All other verticals curve in to a vanishing point. A horizontal line that is not at eye level would have to be curved in order to look straight.

 

[Robert Wilson]

What a brilliant statement! Or perhaps how much one imbibes from the glass.

I'm glad there are two of us who properly understand the theory of all this.

Cheers

 

[[70521]]

My wife, who is normally a perceptive and thoughtful soul is convinced that the horizon appears to have more curvature in the NW of England eg Irish Sea viewed westwards from Wales compared to say the horizon in the south say, the channel viewed southwards from the S coast. I have no views on this but I would be interested if anyone else has the thought that certain places appeared to have more curvature at the horizon than others. Any ideas?

The west is rising and the east is sinking due to the Ice Age.

Personally, I think it is because of the better light in Wales, Cornwall and other Celtic nations.

 

[sarabande]

oh hurray ! I have always imagined that I was wrong in thinking the horizon curved downwards at the L and R edges.

The horizon is curved downwards , and the effect is more marked th ehigher you go. The curvature is the reciprocal of the curvature angular radius in radians.

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