Food for thought

First, let's imagine a whiteboard.  This whiteboard will serve as our field of vision.  Anything on the whiteboard we can "see," and anything not on the whiteboard is outside of our field of vision.  Say this whiteboard is 10m long, and 3m high.  Pretty big whiteboard, plenty big enough to encompass our whole field of vision, even if we stand a foot or two away.

Now, let's draw a circle on this whiteboard.  Let's start it at a 1m radius.  This circle neatly fits in the center of the whiteboard, and we can clearly see that it is, in fact, a circle.  Now, let's make that circle a little bit larger.  Let's make it's radius 2m (we will draw this so that the bottom of the circle is cut off, and we can see the top of it).  Some of this circle is no longer in our field of vision, but the top is still curved enough that we can still see that it is a circle.

Now for a jump: let's make the circle a radius of 5m.  Once again, we will draw this so that the top of the curve is visible.  Now, most of the bottom is cut off.  The circle looks more like a bump, from what we can see.  But it is still no stretch of the imagination that this is still, in fact, a circle.

Another jump: A circle with  a radius of 20m.  Now all we can see is a gentle curve, rising less than 2 m from endpoint to endpoint.  Still, we can presume from the visible curve that it is a circle.

Yet another jump:  A circle with a radius of 100m.  The curve remaining inside the whiteboard is scarcely visible.  One must draw a line from endpoint to endpoint on the whiteboard to see it very clearly.  It almost looks like a straight line.

One more jump:  A circle with a radius of 1km.  No curve is readily visible.  Only with a straight line from endpoint to endpoint can we perceive the tiniest of deviations from it.

This is the time I remind you that this whiteboard is 10m in length.  Pretty long whiteboard.

I lied, there's another jump:  Finally, a circle with a radius of 500km.  Even with the straight line from endpoint to endpoint, there is no repeat no perceptible difference.  One more time: it is impossible to see any difference between the straight line and the curve.  Yet we are still at 1/30th of the radius of the Earth.

The reason it seems that the earth is flat and that there is no curvature to it is that the radius of the "circle" we are observing is so large.  We can't see all of it, and the part we can see curves so little, it's impossible to detect.

Also, astronauts.

Yes, if the earth were a big enough sphere, standing on it would be indistinguishable from a flat surface. However, just because it could be that way does not mean it has to be that way. Flat earthers have a keen understanding of both flat and round earth theories. You have blown no ones mind today.

Yes, and if we looked at a sufficiently large banana we would not be able to distinguish it from a flat surface either. There is no more reason to believe the earth is a banana than there is that it is a beach ball.

"This is the time I remind you that this whiteboard is 10m in length.  Pretty long whiteboard."

Yeah, I guess that's pretty long for a whiteboard alright, but let me blow your mind with this: my field of vision is MUCH LONGER than your 10m whiteboard. 

Yes, and if we looked at a sufficiently large banana we would not be able to distinguish it from a flat surface either. There is no more reason to believe the earth is a banana than there is that it is a beach ball.

Quite right. The Round Earth Theory is nothing more than a delusion which attempts to explain away our experience of living on a plane with fantasy and conjecture.

"Reality is that which, when you stop believing in it, doesn't go away." -- Philip K. Dick

Quite right. The Round Earth Theory is nothing more than a delusion which attempts to explain away our experience of living on a plane with fantasy and conjecture.

"Reality is that which, when you stop believing in it, doesn't go away." -- Philip K. Dick

Tom, I find it rather interesting that you would choose to quote an author of science fiction on the nature of reality.  Especially since Philip K. Dick was prone to delusions of his own.

Basically I agree with what Ski said. All the OP managed to convey was that you can't observe the difference between a large sphere and a flat surface, but such is true for all objects of sufficient size. We have no reason to believe that the Earth is anything but what it is observed to be at our relative perspective.

Quote from: Tom Bishop on September 30, 2012, 12:50:01 PM

Quite right. The Round Earth Theory is nothing more than a delusion which attempts to explain away our experience of living on a plane with fantasy and conjecture.

"Reality is that which, when you stop believing in it, doesn't go away." -- Philip K. Dick

Tom, I find it rather interesting that you would choose to quote an author of science fiction on the nature of reality.  Especially since Philip K. Dick was prone to delusions of his own.

Markjo, I find it rather interesting that you felt the need to post an ad hominem about the author of a quote, rather than just taking the quote at face value. You also added very little to the discussion itself.

Markjo, I find it rather interesting that you felt the need to post an ad hominem about the author of a quote, rather than just taking the quote at face value. You also added very little to the discussion itself.

I made no such attack against the author of that quote.  For some odd reason of other, Tom doesn't seem to think that authors of science fiction are credible sources, so I merely pointed out that Philip K. Dick was an author of science fiction. 

As for the notion not having any reason to believe that the Earth is anything but what it is observed to be at our relative perspective...  Well, I see no reason to dismiss the notion the earth being a giant sphere or banana if our observations do not contradict those shapes.

Let me quote Albert Einstein from his unknown diaries,
"I have found to the resolution of truth, that the earth is a cube. This might surprise many, so I want you to keep these notes. Keep them til the time comes."
the earth is a cube, there's nothing beside this factum.