[Pseudoscience-is-malarkey (OP)]

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[chiralSPO]

A hollow spherical earth would only require that the earth be made of materials with properties that aren't the actual properties of what the earth is actually made of, but nothing physically impossible about that kind of object existing. (what it would be made of and how it would have come to be could be very interesting)

An actual flat earth that somehow generates the uniform gravitational field and atmosphere without accelerating away from nearby objects (which happen to be spheres?) with apparently independent (but interacting) gravitation fields, would require some very different fundamental theories of physics and cosmology.

One might theoretically be able to achieve some uniform gravitational field by varying the density and/or thickness of the flat earth and keep our current understanding of gravity, but it would not account for all of what we observe (obviously)

[Bored chemist]

People who have seen it tell us it is round, but that doesn't rule out being hollow.

[Eternal Student]

Hi.
    I don't know.
You might get opinions more quickly if you put a Poll up on the top of the post.

I'd say a Flat Earth is more plausible.
Why?  Mainly since everyone else has said hollow... but here's one really good scientific reason:
    Gravity.  If we can assume that the earth is round and it's radius is established then we can estimate the amount of mass at the surface of the earth.  It's nowhere near enough to explain the acceleration, 1g, that we observe on the surface of earth.

Reference source:  "How we know what lies at earth's core",  BBC - Earth.   http://www.bbc.co.uk/earth/story/20150814-what-is-at-the-centre-of-earth

Best Wishes.

[Kryptid]

Why?  Mainly since everyone else has said hollow... but here's one really good scientific reason:
    Gravity.  If we can assume that the earth is round and it's radius is established then we can estimate the amount of mass at the surface of the earth.  It's nowhere near enough to explain the acceleration, 1g, that we observe on the surface of earth.

That would also depend upon how hollow it is. If the void in the center is small enough, it would be perfectly possible to construct something that looks like Earth from the outside from known materials while maintaining 1G of surface gravity (barring the fact that it would collapse in on itself).

[Colin2B]

I’m with @chiralSPO on this. A flat earth requires 4 elephants and a turtle, and getting those into pressure suits is going to be impossible. Worse than getting the kids ready for school.

One might theoretically be able to achieve some uniform gravitational field by varying the density and/or thickness of the flat earth and keep our current understanding of gravity, but it would not account for all of what we observe (obviously)

I seem to remember having an over-the-meal-table discussion with our kids on this one. Flat earth had come up at school and it makes an interesting talking point, including astronomy etc.

I’d still go with the lemmings hollowing out the interior.    (for @Zer0 )

[Bored chemist]

A minute's thought about bridges tunnels and caves will convince you that a "slightly hollow" Earth is possible.
But then again, the Earth is a flattened sphere.

[Zer0]

It might be Hollow, but Most Certainly not Shallow.

Six Protons per 1.3 cubic yards.

Expanding in every Direction.

Not curving Positively or Negatively.

Only a 0.4 percent margin Error.

PS - A Round Dot on a Flat Page.
😎
(4 Colin)

[TommyJ]

Another massive part of observations and research showing, that Earth is not flat and not hollow.

Based on magnetic field.
https://en.wikipedia.org/wiki/Earth%27s_magnetic_field
https://en.wikipedia.org/wiki/World_Magnetic_Model

The Earth’s magnetic field looks like that which would be produced by a bar magnet at the center of the Earth, with the North Magnetic Pole corresponding to the South Geographic Pole and vice versa. This dipolar (two poles) configuration applies near the surface of the Earth, but further out the magnetic field is distorted by the solar wind

https://ase.tufts.edu/cosmos/view_picture.asp?id=326

The International Geomagnetic Reference Field (IGRF) is a standard mathematical description of the large-scale structure of the Earth's main magnetic field and its secular variation.
World Magnetic Model is usually assumed that only terms up to degree 14 or less have their origin in the core. These have wavelengths of about 2,000 kilometres (1,200 mi) or less. Smaller features are attributed to crustal anomalies.
Even the oceans contribute to Earth's magnetic field.Seawater is an electrical conductor, and therefore interacts with the magnetic field. Though this interaction is relatively weak.

These are regular measurements, models which are available for Earth. Other planets have their paths and research, which may unsurprisingly make some similarities.

[yor_on]

Oh yee you doubters. Our most highly esteemed colleague Sir Terry Pratchett have personally documented the existence of such a world. I dare you to refute the evidence. Just watch out for elephant dung.

[neilep]

I think its a flat hollow Earth 

[Eternal Student]

Hi Neilep,
  Well, you're right.   It is flat in places and there are some underground caverns in some places.

[neilep]

Hi Neilep,
  Well, you're right.   It is flat in places and there are some underground caverns in some places.

Thank ewe @Eternal Student  like a flat yet bubbly pancake !

cheers chum 

[neilep]

I know a Flat Earther !

https://www.thenakedscientists.com/forum/index.php?topic=73016.msg546892#msg546892

[emelymorris]

The hollow Earth hypothesis is a frequently used name for pseudoscientific, fantastic and esoteric hypotheses about the existence of a vast cavity or cavities inside the Earth, the dimensions of which are comparable to the dimensions of the Earth itself.
That the Earth is flat and hollow is the thinking of people, partly a fantasy. These are the views of some people on Earth, I think that they are equally powerful, and it is clear that they are unrealistic.