International Latitude Service facts for kids
The International Latitude Service (ILS) was a special group created in 1899. It was started by the International Geodetic Association. Its main job was to study how the Earth's axis moves and changes. These changes can affect our latitude (how far north or south you are on Earth).
Scientists wanted to understand things like polar motion (the Earth's poles wobbling a bit), precession (a slow change in the Earth's axis direction), and the Chandler wobble (a small, natural wobble of the Earth).
Contents
How the Service Started
In 1891, a scientist named Wilhelm Julius Foerster talked about a discovery by Seth Carlo Chandler. Chandler had found evidence of polar motion, which another scientist, Leonhard Euler, had predicted way back in 1765. This discovery was important because it affected how we measure latitudes.
Foerster suggested that the International Geodetic Association should study this movement in a planned way. So, in 1895, they decided to create the International Latitude Service. Its main office was in Potsdam, Germany, and Friedrich Robert Helmert was in charge. Regular observations began in 1899. After 1916, the service continued its work, led by Raoul Gautier from the Geneva Observatory.
The Original Observatories
The first International Latitude Observatories were a group of six special stations. They were all built very close to the 39° 08' north latitude line. This alignment helped them collect and compare data in a consistent way.
The first six observatories were in these locations:
- Gaithersburg, Maryland, United States
- Cincinnati, Ohio, United States
- Ukiah, California, United States
- Mizusawa, Iwate, Japan
- Charjui, Turkmenistan
- Carloforte, Italy
How They Studied the Stars
The observatories had a special program to study stars. They looked at 12 groups of stars, and each group had six pairs of stars. Every night, each station would observe two of these star groups following a set schedule. Later, they would compare their measurements with the data collected by the other stations. This helped them track the tiny movements of the Earth's axis.
Changes Over Time
Over the years, some of the original stations had to close because of money problems or wars. However, a new station was opened in Uzbekistan after World War I.
The information collected by these observatories is still very useful to scientists today. This data helps them study:
- Polar motion (the Earth's wobble)
- The physical properties of our planet
- Climatology (the study of climate)
- Satellite tracking and navigation
The Final Observatories
The last six observatories that were part of the service were located in these places, listed from East to West:
- Mizusawa, Japan: National Astronomical Observatory of Japan, Mizusawa VERA Observatory 39°08′6″N 141°07′54″E / 39.13500°N 141.13167°E
- Kitab, in Uzbekistan: 39°08′0″N 66°52′54″E / 39.13333°N 66.88167°E
- Carloforte, Italy: 39°08′13.76″N 8°18′41.90″E / 39.1371556°N 8.3116389°E
- Gaithersburg, Maryland, USA: Gaithersburg Latitude Observatory 39°08′12.51″N 77°11′55.85″W / 39.1368083°N 77.1988472°W
- Cincinnati, Ohio, USA: 39°08′20.45″N 84°25′24″W / 39.1390139°N 84.42333°W
- Ukiah, California, USA: 39°08′14.26″N 123°12′42.54″W / 39.1372944°N 123.2118167°W
What Happened Next
In 1962, the International Latitude Service was renamed the International Polar Motion Service (IPMS). Then, in 1987, a new organization called the International Earth Rotation Service (IERS) was created, and it took over the work of the IPMS.
See also
In Spanish: Servicio internacional de latitud para niños
- List of astronomical observatories
