2006-10-12 15:50:58 · 18 answers · asked by Anonymous in Science & Mathematics ➔ Astronomy & Space
The fact that nobody can find an edge is good evidence. The fact that you can see the altitude of the north star get less and less as you travel south, and that the north star cannot be seen from anywhere south of the equator is also good evidence. The curved shape of Earth's shadow on the Moon during a lunar eclipse is good evidence. The fact that the angles of a triangle drawn from Honolulu to Tokyo to Sidney do not add up to 180 degrees is good evidence. The way ships disappear over the horizon, with first the hull, then the smoke stack and last the top of the mast disappearing is good evidence. And of course, now days, the view from space that we have all seen in photographs is good evidence.
2006-10-12 15:53:23 · answer #1 · answered by campbelp2002 7 · 1⤊ 0⤋
Even (educated) ancient people were aware of the roundness of the earth. When ships sailed off to sea, even through telescopes, those boats would seem to sink lower and lower until only the top of the masts would be visible.
A famous experiment was done by Ptolemy, (I think) in which he planted a stick of a certain length in the ground at exactly noon on the day of the summer solstice and measured the length of the shadow.
The next year on the same day, he performed the same experiment in a different city, a known distance away from the other. Since he knew the sun's position to be the same, he was able to judge the shape of the Earth and even estimate its circumference. He was off the true number, but he had the principle right, and his result was pretty close considering the tools he had to calculate with.
Space missions to Jupiter and other Outer planets launched from Earth, slingshotted around the sun, then rocketed out to their destinations. If Earth weren't round this path would not be possible.
And actually, The Earth isn't completely spherical. The spinning makes it bulge a bit around the equator.
2006-10-12 23:02:54 · answer #2 · answered by chocolahoma 7 · 0⤊ 0⤋
In Columbus's day it was generally accepted te world was spherical. Or, like a ball. Either way.
Yet, through time, despite alarming evidince against them, Flat Earthists have insisted that all sphere theories (spheriories?) are falsehoods. The US alone has spent millions of dollars to assert the spherical Earth "postulate". Clearly this has been a wise choice, seeing what zillions have been earned through this "discovery".
I suggest you build a rocket, teavel to space, and examine the Earth properly, to attain your answer.
2006-10-12 23:09:40 · answer #3 · answered by Flounder 3 · 0⤊ 0⤋
The earth's shadow on the moon is spherical. Also, if you look at the sail of a ship (from land) as it goes further into the see it appears to sink. That's how the greeks figured it out
2006-10-12 22:54:37 · answer #4 · answered by Steve R 2 · 1⤊ 0⤋
Here's a very simple demonstration that anybody can observe without any expensive equipment at all.
The next time there's a lunar eclipse, just look at the earth's shadow as it moves across the surface of the moon. You will be able to plainly see that the earth is round. Voila!
That proof should be strong enough for even the goofiest conspiracy theorists who think the moon landings were fake. If their own eyes don't convince them, then they would have to say their eyes were part of the conspiracy.
2006-10-12 22:52:28 · answer #5 · answered by Jim 5 · 4⤊ 0⤋
The shape of the earth is actually an oblate ellipsoid of revolution. This was theorized by Sir Isaac Newton and was published in 1714 by the French who proved it by running their chains of quadralaterals (surveying technique) around the equator.
2006-10-12 22:56:46 · answer #6 · answered by ybot84 2 · 1⤊ 0⤋
The best evidence is photographs and observations from space where the curvature of the earth can be seen directly.
2006-10-12 22:55:06 · answer #7 · answered by DanE 7 · 1⤊ 0⤋
There is tons of mathmatical evidence as well as physical evidence. The fact you can travel around the world and in one direction and return exactly where you started is some simple evidence.
2006-10-12 22:54:23 · answer #8 · answered by sshazzam 6 · 2⤊ 0⤋
once upon a time this dude named Ferdinand Magellan led an expedition that successfully circumnavigated the world.
that and...
we've got pictures from outer space of the Earth.
2006-10-12 22:55:07 · answer #9 · answered by vgirl 2 · 1⤊ 0⤋
The one dude who sailed around the world. The guy who flew around the world. the guy who ran most of the way around the world. and the pictures from space and the guys who flew around the in a space shuttle.
2006-10-12 23:56:46 · answer #10 · answered by Yup 2 · 0⤊ 0⤋