
	Where results make sense

Topic: Syene

Related Topics

Aswan

Stadia

Eratosthenes

Longitude

Circumference

Tropic of Cancer

In the News (Mon 6 Jul 09)

Northern Trust

Marvin Harrison

Peter Chernin

Gary Locke

Match Play

Penelope Cruz

Mickey Rourke

AR Rahman

Danny Boyle

Hugh Jackman

	History of geodesy - Wikipedia, the free encyclopedia
		At the same time, he observed the sun was not directly overhead at Alexandria; instead, it cast a shadow with the vertical equal to 1/50th of a circle (7° 12').
		From these observations and "known" facts, Eratosthenes concluded that, since the angular deviation of the sun from the vertical at Alexandria was also the angle of the subtended arc, the linear distance between Alexandria and Syene was 1/50 of the circumference of the earth or 50 x 500 = 25,000 miles.
		Actually, Syene is 37 miles to the north; (2) the true distance between Alexandria and Syene is 453 miles and not 500; (3) Syene lies 3° 30' east of the meridian of Alexandria; (4) the difference of latitude between Alexandria and Syene is 7° 5' rather than 7° 12' as Eratosthenes had concluded.
	en.wikipedia.org /wiki/History_of_Geodesy (1449 words)

	Eratosthenes (Site not responding. Last check: 2007-10-22)
		In Alexandria, almost due north of Syene, he knew that the sun was not directly overhead at noon on the same day, because a vertical object cast a shadow.
		Knowing also that the arc of an angle this size was 1/50 of a circle, and that the distance between Syene and Alexandria was 5000 stadia, he multiplied 5000 by 50 to find the earth's circumference.
		Where d = distance between Syene and Alexandria, A = 360 degrees assumption of round earth, a = shadow angle of vertical stick, D = to be determined (circumference).
	www.grecoreport.com /eratosthenes.htm (938 words)

	[No title] (Site not responding. Last check: 2007-10-22)
		Eratosthenes assumed that the city of syene was on the Tropic of Cancer because at midday on the summer solstice a well, especially dug for this reason, was illuminated to its bottom by the sun's rays.
		North Pole Tropic of Cancer Alexandria rays of sun Equator Syene Since the angle of the sun's rays on the summer solstice is 90 degrees, then both vertical lines extended to the center of the earth would form an angle of 7 degrees 12 minutes (all three angles totaling 180 degrees).
		Therefore, the arc distance between Syene and Alexandria relative to the earth's circumference would be 7 degrees 12 minutes/360 degrees, or 1/50 of the circumference.
	maps.unomaha.edu /Peterson/carta/Notes/eratosthenes.html (448 words)

	Sun-Earth-Moon: Sizes and Distances -- SIZE OF EARTH
		This observation is in fact a measurement of the curvature of the Earth's sphere between Syene and Alexandria, and once the length of this small arc between the two cities is known, the circumference of the entire Earth may be determined.
		The length of the shadow is to the distance between Syene and Alexandria as the height of the obelisk is to the radius of the Earth.
		Syene to Alexandria Length of the Shadow ------------------- = -------------------- Radius of the Earth Height of the Obelisk
	www.astro.washington.edu /archive/astro211_Wi2001/eratosthenes2/rung1.html (610 words)

	CATHOLIC ENCYCLOPEDIA: Syene
		Syene (Egyptian, Souanou, Coptic, Souan) was originally the marketplace of the island of Elephantine (in Egyptian, Abou).
		The Syene of the Romans to the southwest of the present city, suffered much from the incursions of the Blemmyes, and from the pest; its inhabitants abandoned it to live in the higher parts built by the Saracens.
		Syene is mentioned by the prophet Ezechiel, who threatened Egypt with devastation "from the tower of Syene even to the borders of Ethiopia" (Ezekiel 30:10).
	www.newadvent.org /cathen/14367a.htm (462 words)

	Untitled Document
		Eratosthenes reported that Syene was due south of Alexandria on the same meridian, and he reported that the distance from Syene to Alexandria was 5,000 stadia.
		Syene is actually almost three full degrees of longitude east of Alexandria The distance from Syene to Alexandria is not 5,000 stadia regardless of what stadia is employed, because Syene is so far east of Alexandria.
		Although the distance from Alexandria to Syene is not equal to 1/50th of the circumference of the earth, the distance from the latitude of Alexandria to the latitude of Philae, six minutes south of Syene at the southern border of ancient Egypt, is equal to 1/50th of the circumference of the earth (7° 12').
	home.hiwaay.net /~jalison/Art4.html (1966 words)

	ASSUMPSIT - LoveToKnow Article on ASSUMPSIT
		On Elephantine Island are an ancient nilometer and de her remains, including a granite gateway built under Alexander 0 e Great at the temple of the local ram-headed god Chnubis or 15 mumis (Eg.
		Syene was one of the bases used by Eratosthenes co his calculations for the measurement of the earth, In Roman in nes Sycnc was strongly garrisoned to resist the attacks of the ne sert tribes.
		Syene appears also th have flourished under its first Arab rulers, but in the 12th B ntury was raided and ruined by Bedouin and Nubian tribes.
	www.1911encyclopedia.org /A/AS/ASSUMPSIT.htm (812 words)

	Notes: Shape and Size of the Earth
		(Syene is the modern city of Aswan, located south of Alexandria, on the banks of the Nile.) The next time June 21 rolled around, Eratosthenes stepped outside, and determined that the Sun was NOT directly overhead as seen from Alexandria, but was 7.2 degrees south of the zenith (the point directly overhead).
		A parallel ray of sunlight strikes Alexandria at an angle of 7.2 degrees from the perpendicular.
		The distance between Alexandria and Syene, as measured on the surface of the Earth, must then be 1/50 of the complete distance around the Earth.' To find the circumference of the Earth, Eratosthenes simply had to find the distance between Alexandria and Syene, and multiply it by 50.
	users.zoominternet.net /~matto/M.C.A.S/notes_size_shape.htm (1232 words)

	Ancient Measurements of the Circumference of the Earth
		Since actually Syene is about 14’ North of this point, somebody assumed that the phenomenon of the sun falling vertically proved correct over a band of 26’ by doubling the figure, assuming a possibility of error in either direction.
		The arc between Draco and Cancer is 1/15 of the meridian drawn through Lysimacheia and Syene, as is indicated by the shadows cast by gnomons; 1/15 of the whole circle is 1/5 of the diameter.
		The datum that there are 20,000 stadia between Lysimacheia and Syene must have been derived from a text that reckoned 18° by a stadion of 1111.1 to the degree, between the Tropic or Syene and the parallel of the Bosphoros (42°12’N); Eratosthenes identifies the latitude of Lysimacheia at the Dardanelles with that of the Bosphoros.
	www.metrum.org /measures/measurements.htm (12676 words)

	Hipparchus (Site not responding. Last check: 2007-10-22)
		Hipparchus compared observations of a solar eclipse in Syene and in Alexandria to determine the distance from the Earth to the Moon.
		Hipparchus measured the distance from the Earth to the Moon during a solar eclipse that was a total eclipse at Syene and a partial eclipse at Alexandria.
		At the same time that an observer at Syene saw the entire Sun blocked by the Moon, one at Alexandria saw 1/5th of the Sun's disk, that is 1/5th of 30 arcminutes of the Sun's disk was visible (The Sun's angular diameter is 30 arcminutes or 1/2 degree).
	astrosun2.astro.cornell.edu /academics/courses/astro201/hipparchus.htm (199 words)

	Math Forum - Ask Dr. Math
		He also knew that Syene was on the same meridian as the city of Alexandria.
		Finally, Eratosthenes knew that the distance between Alexandria and Syene was 5000 stadia, a Greek unit for measuring length.
		We know that the distance between Alexandria and Syene is about 500 miles, so using his fraction 1/50, we can get the circumference of the earth to be about 500 * 50 = 25000 miles, which is about right.
	mathforum.org /library/drmath/view/58988.html (737 words)

	IMSA Astrophysics: Distance Ladder
		The sun could not be directly overhead in Syene and not be directly overhead in Alexandria if the world were flat.
		He found that the shadow was cast at an angle of 7.2°, and so he surmised that the distance from Alexandria to Syene represented 7.2°/360° = 1/50th of the circumference of the earth.
		Eratosthenes demonstrated that the distance from Alexandria to Syene, regardless of units used, was 1/50th of the entire circumference of the earth, and that is correct!
	staff.imsa.edu /science/astro/astrometry/ground1.html (404 words)

	Sun-Earth-Moon: Sizes and Distances -- SIZE OF EARTH (Site not responding. Last check: 2007-10-22)
		Being in Alexandria, which was located more or less due north of Syene, he could measure the length of a shadow cast by an obelisk at the same time, noon on the summer solstice.
		This measurement, along with the height of the obelisk, gave him the angle that the Sun appeared south of the zenith in Alexandria, an angle he determined to be 7.2 degrees.
		This is in fact a measurement of the curvature of the Earth's sphere between Syene and Alexandria, and once distance of this small arc is known, the circumference of the entire Earth is determined.
	www.astro.washington.edu /labs/eratosthenes/rung1.html (470 words)

	Khorsheed.com - 60 Minutes
		He had heard that in the nearby town of Syene midday sunlight shines straight down to the bottom of deep wells on the same day each year, indicating that the Sun was directly overhead in Syene.
		Eratosthenes reasoned that the difference in the angle of incoming sunlight was due to the curvature of Earth's surface, and so by measuring this angle, he related the distance between Alexandria and Syene to the total dimension of the globe.
		It was seven degrees away from the zenith, meaning Syene must be seven degrees away from Alexandria as measured on the circle that is Earth's circumference.
	www.khorsheed.com /pages/space4.html (238 words)

	lesson3.html (Site not responding. Last check: 2007-10-22)
		Finding the distance (not to scale) from A (Alexandria) to C (Syene) turned out not to be as formidable a task as circumnavigating the globe and it's the one that Eratosthenes was able to do.
		One day at his library Eratosthenes read in a papyrus book that in the frontier outpost of Syene vertical sticks cast no shadow and a reflection of the sun could be seen at the bottom of the well at noon on June 21st.
		Syene (today known as Aswan) is located very close to that latitude.
	njnie.dl.stevens-tech.edu /noonday/lesson3.html (867 words)

	Iranica.com - ELEPHANTINE
		The island was always the administrative center of the southernmost province of Egypt, controlling the first cataract and the main frontier post en route to Nubia, but during the Achaemenid occupation (525-402, 342-332 B.C.E.) the military garrison (Aram.
		Syene was a port of call for contingents of the various ethnic elements of the empire (Persians, Phoenicians, Chorasmians, Medians, Assyrians, and Babylonians), with chapels for their divinities and the administrative seat of the Achaemenid civilian governor (fratarak).
		In Syene a number of tombs of Semitic peoples have been excavated (Kornfeld).
	www.iranica.com /articles/v8f4/v8f408.html (994 words)

	THE EQUINOX SCIENCE AND MATH EXPERIMENT (Site not responding. Last check: 2007-10-22)
		In the great library in Alexandria he read that a deep vertical well near Syene, in southern Egypt, was entirely lit up by the sun at noon once a year.
		All you need to do is place a vertical stick (shaft) into the ground at your school and when the sun reaches it's highest vertical assent for the day (solar noon therefore the shadow length will be the shortest), measure the angle of the shadow of the stick (a).
		Using a globe or an atlas the distance between your location and the equator (d in equation) can be determined and the circumference can be calculated.
	www.huntel.net /rsweetland/science/actPlans/earth/equinoxRDS.html (402 words)

	Carl Sagan's Story (Site not responding. Last check: 2007-10-22)
		He was also the director of the great library of Alexandria, where one day he read in a papyrus book that in the southern frontier outpost of Syene, at noon on June 21 vertical sticks cast no shadows.
		For the observed difference in the shadow lengths, the distance between Alexandria and Syene had to be about seven degrees along the surface of the Earth; that is, if you imagine the sticks extending down to the center of the Earth, they would there intersect at an angle of seven degrees.
		Eratosthenes knew that the distance between Alexandria and Syene was approximately 800 kilometers, because he hired a man to pace it out.
	njnie.dl.stevens-tech.edu /noonday/cosmos.html (539 words)

	Eratosthenes of Cyrene
		And it is necessary that the distance between Syene and Alexandria is one-fiftieth of the Earth's circumference.
		He reasoned that the change in angle of the shadow was caused by the spherical shape of the Earth (Aristotle and others knew this earlier) and that it would be possible from this angle to obtain the circumference of the Earth..
		Eratosthenes measured the distance to the sun as 804000000 stadia and the distance to the Moon as 780000 stadia from data obtained during lunar eclipses.
	www.mlahanas.de /Greeks/Eratosthenes.htm (1790 words)

	Christopher Hirata's E-Home (Site not responding. Last check: 2007-10-22)
		Erastosthenes concluded that the direction "down" (toward the center of the Earth) was different by seven degrees in Alexandria from in Syene, thus allowing him to determine the distance to the center of the Earth as 4,000 miles (6,400 km) (see figure below).
		On the day of a solar eclipse, the Moon passed in front of the Sun, casting a shadow on the Earth and totally blocking the Sun as seen from Syene.
		As seen from Alexandria, however, a thin arc of the Sun a tenth of a degree wide was still visible.
	www.princeton.edu /~chirata/mmr/m020121.html (854 words)

	Eider Suso: Share: June 2004 Archives
		Erastosthenes was the director of the great library of Alexandria where one day he read in a papyrus book that in the southern frontier outpost of Syene, near the first cataract of the Nile, at noon on June 21 vertical sticks cast no shadows.
		He asked himself how, at the same moment, a stick in Syene could cast no shadow and a stick in Alexandria, far to the north, could cast a pronounced shadow.
		For the difference in the shadow lengths, the distance between Alexandria and Syene had to be about 7 degrees along the surface of the Earth.
	www.eidersuso.com /share/2004_06.html (724 words)

	The Eratosthenes Project
		This technique is based on the observation by Eratosthenes that the sun is directly overhead at noon in Syene in southern Egypt on the first day of summer.
		Since Eratosthenes knew that the earth was a sphere, he correctly reasoned that if he could determine the altitude of the noon sun at some other location on the first day of summer, AND if he knew the distance between these two locations, he could compute the circumference of the earth as a simple ratio.
		However he actually obtained the data, the difference between the noon sun elevations at Syene and Alexandria on the first day of summer was approximately 7 degrees.
	www.phys-astro.sonoma.edu /observatory/eratosthenes (774 words)

	[No title] (Site not responding. Last check: 2007-10-22)
		In one of the most elegant experiments ever reported, he calculated the circumference of the Earth to be approximately 25,000 miles, what we know it to be today.
		While at Alexandria, the same day and time (noon in Syene), the Sun would strike any vertical object, in this case an Obelisk, at a angle that could be measured.
		The 5000 stadia (500 miles) between Alexandria and Syene was, as well, 1/50th the distance around the entire Earth.
	www.sciencedigest.org /eratos_ahmes.htm (257 words)

	Math Lair - Eratosthenes (Site not responding. Last check: 2007-10-22)
		While the idea that the Earth is round was not uncommon among ancient Greek philosophers, Eratosthenes was able to demonstrate this fact, and calculate the Earth's circumference accurately.
		The ancients noticed that, in the city of Syene (modern day Aswan), at noon on June 21, the sun is directly overhead.
		The conclusion that Eratosthenes drew is that the surface of the Earth had to be curved.
	www.stormloader.com /ajy/eratosthenes.html (605 words)

	Measuring the Moon's Diameter (Site not responding. Last check: 2007-10-22)
		Eratosthenes noticed that travelers reported that at noon on the first day of summer, columns in the city of Syene, Egypt cast no shadows, and that sunlight would reach the bottom of deep wells.
		So the Earth's circumference must be about 50 times the distance between Alexandria and Syene.
		It was determined that Alexandria was exactly 5000 stadia from Syene, (the stadium being the Greek standard unit of distance).
	resources.yesican-science.ca /eratosthenes/history.html (319 words)

	Re: Who discovered the world was round and what year was it?
		What he did was use the information that, at noon on the Summer Solstice, the sun shone to the bottom of a well in Syene (now called Aswan), Egypt.
		He used that angle to calculate what fraction of the Earth's circumference (which is 360°) was between Alexandria and Syene.
		Since he knew the distance to Syene, and that it was exactly south of Alexandria, he was able to calculate the Earth's circumference.
	www.madsci.org /posts/archives/jan2002/1012504968.Sh.r.html (263 words)

Try your search on: Qwika (all wikis)