# When the sun was directly overhead in syene, why was it not directly overhead in alex

by pbody
 P: 2,526 Your answer is incorrect. The sun can only be directly overhead a town if that town lies between the Tropic of Cancer in the northern hemisphere and the Tropic of Capricorn in the sourthern. Hint: Check the latitude of the tropics as well as Alexandria and Syene. You might wish to change your answer. Hint 2: Read the wikipedia article on Syene
 P: 41 On Wikipedia I read well what I interpreted from the reading is the Aswan is the driest place on earth 2001 was the first time this place has seen rain in seven years. The latitude for the Tropic of Cancer is said to be 23° 26′ 16″ The latitude of Alexandria is 31.2000° N, 29.9167° E The latitude of Syene is 24.0667° N, 32.9167° E Oh the Tropic of Cancer and Syene are one of the same O.K. The latitude of the Tropic of Capricorn is 23° 26′ 16″ So would the answer be there are only two spots on planet earth that the Sun can be directly over head and that is in Syene and Chile?
P: 2,526

## When the sun was directly overhead in syene, why was it not directly overhead in alex

 Quote by pbody On Wikipedia I read well what I interpreted from the reading is the Aswan is the driest place on earth 2001 was the first time this place has seen rain in seven years.
I meant this bit...

 The latitude of the city that would become Aswan – located at 24° 5′ 23″ – was an object of great interest to the ancient geographers. They believed that it was seated immediately under the tropic, and that on the day of the summer solstice, a vertical staff cast no shadow. They noted that the sun's disc was reflected in a well at noon. This statement is only approximately correct; at the summer solstice, the shadow was only 1/400th of the staff, and so could scarcely be discerned, and the northern limb of the Sun's disc would be nearly vertical.
Alex is too far north for the sun to ever be directly overhead. The earth doesn't tilt that much.
P: 2,526
 Quote by pbody On Wikipedia I read well what I interpreted from the reading is the Aswan is the driest place on earth 2001 was the first time this place has seen rain in seven years. The latitude for the Tropic of Cancer is said to be 23° 26′ 16″ The latitude of Alexandria is 31.2000° N, 29.9167° E The latitude of Syene is 24.0667° N, 32.9167° E Oh the Tropic of Cancer and Syene are one of the same O.K. The latitude of the Tropic of Capricorn is 23° 26′ 16″ So would the answer be there are only two spots on planet earth that the Sun can be directly over head and that is in Syene and Chile?
No it can be overhead anywhere between the tropics (at different times of the year).

Syene (24°N) is roughly on a tropic (23°N) so at noon on mid summers day the sun will be almost directly overhead.

Alexandria (29.9° E) is roughly due north of Syene (32.9° E) so at the same time and date it's easy to compare the length of the shadow. You don't even need to go to Syene you can assume it's zero.
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P: 9,281
 Quote by pbody 1. When the sun was directly overhead in syene, why was it not directly overhead in Alexandria 3. because the angle 7.1° can correlate to the length of distance between alexandria and syene which is 7.1/360 which would be 1/50 of the earth but a different distance than syene I am sure on another day other than June 22 the sun would be directly over alexandria due to the fact of the Earth's angle and the sun and the earths rotation.
Siene is at the Tropic of Cancer, and Alexandria was due north of Syene. So the sun is never overhead in Alexandria. The question is why the sun is not overhead in both town at noon, on the same day. Hint: what would be the situation with a flat Earth?
Erathosthenes estimated the circumference of Earth but it was more basic that his observations proved that the Earth was not flat.

ehild
 P: 41 With a flat earth there would be no significant angle change? because there would really be no angles other than I guess the suns rotation but if the earth was flat than the sun was something completely different. Wouldn't the answer be because of the angular differential or something?
P: 41
 Quote by CWatters I meant this bit... Alex is too far north for the sun to ever be directly overhead. The earth doesn't tilt that much.
Can the same experiement be done at the Tropics of capricorn with the same calculations of a fraction of a shadow or only in the Tropics of Cancer?
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P: 9,281
 Quote by pbody With a flat earth there would be no significant angle change? because there would really be no angles other than I guess the suns rotation but if the earth was flat than the sun was something completely different. Wouldn't the answer be because of the angular differential or something?
If the Earth was flat the Sun rays would make the same angle with the surface at the same time. Erathosthenes knew that the Sun shined into that deep well in Syene at noon June 22, but it cast shadow in Alexandria at the same time. So the surface of the Earth must be tilted with respect to the sun rays in Alexandria, while it is normal to the rays in Syene : it must be curved.

ehild
 HW Helper Thanks P: 9,281 The Tropic of Capricorn would be appropriate, too. Only the ancient Greeks did not travel there... ehild
 P: 41 That's pretty cool one of the first documented discoveries showing the earth had angles actually, a little awesome discovering it as well!! Well for me at least!!

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