Tsontos
07-26-2006, 01:23 PM
Ancient Greeks knew the Earth was round
July 26, 2006
It always seems amazing how much ancient people knew without using the sophisticated methods of modern times.
For example, the Greeks knew not only that the Earth was round, but also just about how big it was. And that was 2,500 years ago!
How could they possibly know this? We might imagine using pictures from space, or plane trips around the world. But in ancient times?
Let's use their reasoning. The stars appear higher the farther south you go. We use that fact when we go south in winter. It's warmer in Florida because the sun is higher.
That shows that the Earth is round — if it were flat, the sun would be just as high everywhere.
For example, the sun is higher in New York than it is in Rutland. The details: at noon, it's about 3-1/2 degrees higher, and New York is 250 miles south of Rutland.
That difference of 3-1/2 degrees is about one-one hundredth of 360 degrees. So the 250 miles must be about one-one hundredth of the distance around the Earth.
So the distance is 100 times 250 — 25,000 miles, which is very much what we're told in school.
That's how the Greeks — using different cities, of course, but the same method — knew just how big our world is. And now we do, too!
Keep looking up!
http://www.rutlandherald.com/apps/pbcs.dll/article?AID=/20060726/NEWS/607260322/1024/NEWS04
I read somewhere that they "computed" the earth's perimeter and their figure was very close to the real one (<5%, if I remember correctly). But I have forgotten the name..
July 26, 2006
It always seems amazing how much ancient people knew without using the sophisticated methods of modern times.
For example, the Greeks knew not only that the Earth was round, but also just about how big it was. And that was 2,500 years ago!
How could they possibly know this? We might imagine using pictures from space, or plane trips around the world. But in ancient times?
Let's use their reasoning. The stars appear higher the farther south you go. We use that fact when we go south in winter. It's warmer in Florida because the sun is higher.
That shows that the Earth is round — if it were flat, the sun would be just as high everywhere.
For example, the sun is higher in New York than it is in Rutland. The details: at noon, it's about 3-1/2 degrees higher, and New York is 250 miles south of Rutland.
That difference of 3-1/2 degrees is about one-one hundredth of 360 degrees. So the 250 miles must be about one-one hundredth of the distance around the Earth.
So the distance is 100 times 250 — 25,000 miles, which is very much what we're told in school.
That's how the Greeks — using different cities, of course, but the same method — knew just how big our world is. And now we do, too!
Keep looking up!
http://www.rutlandherald.com/apps/pbcs.dll/article?AID=/20060726/NEWS/607260322/1024/NEWS04
I read somewhere that they "computed" the earth's perimeter and their figure was very close to the real one (<5%, if I remember correctly). But I have forgotten the name..