"Where's The Edge?"

[togor]

Red if satire it's pretty dry but sure, okay.

[Merc]

If the earth were flat, you should be able to see right to the edge - on a very clear day. You go to sea at all, you can see the horizon from main deck. Go up to O2/climb to the maintop and you can see a horizon that is farther away. That means your ship is on a curved surface. If you can sail around it one direction and return to home port, it is a surface with a closed curve.

It's a myth that sailors were terrified they might fall off the edge. Press-ganged landsmen, maybe. There was plenty else to fear once you sailed past the Pillars of Hercules.

jn

I believe that seven miles is the maximum distance an object can be seen at the water level. The distance increases in proportion to the height of both objects. It’s interesting to be driving along Interstate 90 in Erie County, PA on a clear day and look out across Lake Erie and be able to see Long Point, Ont and realize that it’s probably about 19 miles away. Of course, portions of I-90 are elevated a hundred or more feet above the water level.

[lyman]

I believe that seven miles is the maximum distance an object can be seen at the water level. The distance increases in proportion to the height of both objects. It’s interesting to be driving along Interstate 90 in Erie County, PA on a clear day and look out across Lake Erie and be able to see Long Point, Ont and realize that it’s probably about 19 miles away. Of course, portions of I-90 are elevated a hundred or more feet above the water level.

I was standing on the beach at Dover (on I was told a rare bright sunny day) in Mar 2008 and could see Calais France,