At this stage in the debate, it's possibly a good point to stand back and reflect on some aspects of the discussion so far.

In terms of large or infinite structures in the known universe no infinite structure has ever been observed, ( I wonder why?) while the largest ‘thing’ ever observed is a pileup of galaxies or galaxy cluster known as SPT2349. This is according to Nature. If you have a subscription you can read up about it here.

https://www.nature.com/articles/s41586-019-1829-4Its actual size is only 10 trillion times larger than our own sun, that's the 1.4 Million km real version.

While this is pretty big, it's a comparative non-entity when compared to anything infinite.

I was in the pub last night talking to a couple of pals of mine one of whom happens to be a prof at a local university in mathematics. I made the mistake of mentioning infinity. You know what happens when you light a blue touch paper, well that was him. One of the first things he said, which I looked up when I got home, was when talking about infinity the first thing you need to realise that it is not and can’t be treated as a number and its a really bad idea if you do.

Consider two infinite lines one made up of an infinite number of millimeters and the other of an infinite number of kilometers. Does it mean that the infinite kilometer line is 1000 times longer than the infinite millimeter line? exactly you can’t think of infinity as a number. Remember that infinity is not a number.

It appears that many contributors did not like my assertion that an infinite object would be composed of infinite atoms and have an infinite mass which would give rise to infinite gravity.

They produced some extremely dubious maths from a dubious source that they asserted ‘proved’ an infinite plane of thickness 4000 miles or so would have a finite gravity of around that of the earth. I would say to them that both they and the ‘mathematician’ that did the calculation do not understand infinity.

While the Greeks did mention infinity, though they really didn’t like it, and Zeno had a think about it but any real understanding of infinity only really came in the early 20th Century. Infinity in either mathematics or philosophy is very very different from considering an infinite object existing in the real world. The science of physical infinities is much less developed than the science of mathematical infinities. The main reason is simply that the status of physical infinities is quite undecided.

For example, think about this. If the earth were an infinite plane, made up of an infinite amount of matter how can there then be any other matter in the universe?

the existence of other galaxies of which billions have been observed would in one fell stroke preclude the existence of an infinite structure existing.

I think that fact kills any idea of there being infinite flat earth existing in either a thought experiment or in the real world.

One of the main problems of this debate has been the use of maths and science to justify one's stance. According to science, the idea of the existence of an infinite flat earth is precluded due to the behavior of mass when subjected or should I say influenced by the presence of a gravitational field. It has been shown that if the object is made of ice then it becomes spherical when it reaches 400km in diameter or 600 if rock. This appears to be a fairly universal law and another reason despite the maths of John Davis that a flat body even finite and the size of the earth, could not exist.