sunbear, we’d have gravity pretty much no matter what. It’s a function of mass, not shape.
“I love God! He’s so deliciously evil!” - Stewie Griffin, Family Guy
Well, if the Earth were flat, who would be living on the other side?..Would you really be able to dig your way to China?
I haven’t lost my mind, I have a tape backup around somewhere.
In addition to the temperature differences Ray mentioned, the density gradient due to altitude will bend the light. Refraction doesn’t need a sharp boundary.
Bob the Random Expert
“If we don’t have the answer, we’ll make one up.”
We’d have gravity, but the gravity field around a disc is a lot different than around a sphere. At the center of the disk there would be no gravity, since the mass around you would radiate away in all directions (other than the small mass equal to the thickness of the disk).
As you move away from the center, what would be ‘down’ would be a direction towards the center of mass, which would be an angle that changed as you moved towards the rim. At the very rim, ‘down’ would be almost parallel to the ground. Better bring your climbing spurs.
A flat disc could not hold an atmosphere of any kind.
If we’re going to let reality intrude, any earth-sized object that started as a disk or a cylinder would very quickly collapse into a sphere through it’s own gravitational attraction.
If we’re not going to let reality bother us, why would we want gravity to change on our flat earth?
p.s. If you tried to dig to China you would eventually dig through the flat earth and fall through the hole. You would fall forever. If you don’t believe me just try it.
“The departure of the church-going element had induced a more humanitarian atmosphere.”
Dorothy L. Sayers
Clouds of Witness
Nope, you wouldn’t fall forever. You’d land on the turtle’s back.
Wouldn’t you hit an Elephant first?
‘They couldn’t hit an Elephant from this dist…!’
Last words of General John Sedgwick
Nope. It’s turtles all the way down. 
Yeah. We all know you couldn’t hit an Elephant from this dist…!
::Reads post::
Yeeeeesh…
And I didn’t even do that on purpose…
Dorothy, I don’t think we’re still getting the straight dope. I think we’ve lifted off a bit.
Ray (Some prefer levity to gravity, whatever the shape of the earth.)