A new world geodetic network
To know the exact size and shape of the earth has long been a goal of scientists. Man's attempts to locate himself and to determine the configuration of his planet date from at least the time of Eratosthenes, about 200 BC. He observed that on a particular day in mid summer the sun shone directl...
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Cambridge University Press (CUP)
1971
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Online Access: | http://dx.doi.org/10.1017/s0032247400062082 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0032247400062082 |
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crcambridgeupr:10.1017/s0032247400062082 2024-03-03T08:48:20+00:00 A new world geodetic network Swanson, L. W. Yeager, J. Austin 1971 http://dx.doi.org/10.1017/s0032247400062082 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0032247400062082 en eng Cambridge University Press (CUP) https://www.cambridge.org/core/terms Polar Record volume 15, issue 99, page 863-870 ISSN 0032-2474 1475-3057 General Earth and Planetary Sciences Ecology Geography, Planning and Development journal-article 1971 crcambridgeupr https://doi.org/10.1017/s0032247400062082 2024-02-08T08:32:27Z To know the exact size and shape of the earth has long been a goal of scientists. Man's attempts to locate himself and to determine the configuration of his planet date from at least the time of Eratosthenes, about 200 BC. He observed that on a particular day in mid summer the sun shone directly down a well in Syene, Egypt (thus the zenith angle=0°). Supposing the earth to be a sphere, he measured the zenith angle on the same day to be 7.2° at Alexandria. His calculation of the distance between the points, based on the travel time of a camel caravan between them and on the assumption that both were on the same meridian, gave him enough information to compute the earth's circumference: 7.2°/360° = l/50. Therefore, the distance between Syene and Alexandria was 1/50th of the earth's circumference. His calculations were about 16 per cent too large. Considering, however, the primitiveness of his measurements and assumptions, his value was remarkably close. Two later determinations were made using this “astrogeodetic” principle, but with little increase in accuracy. Article in Journal/Newspaper Polar Record Cambridge University Press Polar Record 15 99 863 870 |
institution |
Open Polar |
collection |
Cambridge University Press |
op_collection_id |
crcambridgeupr |
language |
English |
topic |
General Earth and Planetary Sciences Ecology Geography, Planning and Development |
spellingShingle |
General Earth and Planetary Sciences Ecology Geography, Planning and Development Swanson, L. W. Yeager, J. Austin A new world geodetic network |
topic_facet |
General Earth and Planetary Sciences Ecology Geography, Planning and Development |
description |
To know the exact size and shape of the earth has long been a goal of scientists. Man's attempts to locate himself and to determine the configuration of his planet date from at least the time of Eratosthenes, about 200 BC. He observed that on a particular day in mid summer the sun shone directly down a well in Syene, Egypt (thus the zenith angle=0°). Supposing the earth to be a sphere, he measured the zenith angle on the same day to be 7.2° at Alexandria. His calculation of the distance between the points, based on the travel time of a camel caravan between them and on the assumption that both were on the same meridian, gave him enough information to compute the earth's circumference: 7.2°/360° = l/50. Therefore, the distance between Syene and Alexandria was 1/50th of the earth's circumference. His calculations were about 16 per cent too large. Considering, however, the primitiveness of his measurements and assumptions, his value was remarkably close. Two later determinations were made using this “astrogeodetic” principle, but with little increase in accuracy. |
format |
Article in Journal/Newspaper |
author |
Swanson, L. W. Yeager, J. Austin |
author_facet |
Swanson, L. W. Yeager, J. Austin |
author_sort |
Swanson, L. W. |
title |
A new world geodetic network |
title_short |
A new world geodetic network |
title_full |
A new world geodetic network |
title_fullStr |
A new world geodetic network |
title_full_unstemmed |
A new world geodetic network |
title_sort |
new world geodetic network |
publisher |
Cambridge University Press (CUP) |
publishDate |
1971 |
url |
http://dx.doi.org/10.1017/s0032247400062082 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0032247400062082 |
genre |
Polar Record |
genre_facet |
Polar Record |
op_source |
Polar Record volume 15, issue 99, page 863-870 ISSN 0032-2474 1475-3057 |
op_rights |
https://www.cambridge.org/core/terms |
op_doi |
https://doi.org/10.1017/s0032247400062082 |
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Polar Record |
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15 |
container_issue |
99 |
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863 |
op_container_end_page |
870 |
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1792505107078709248 |