International Latitude Service facts for kids
The International Latitude Service (ILS) was a special group created in 1899. Its main job was to study how the Earth's axis moves and wobbles. This movement causes small changes in our planet's latitude, which is how far north or south a place is from the Equator.
The ILS helped scientists understand these tiny shifts, which are caused by things like polar motion (the Earth's poles moving slightly) and the Chandler wobble (a small, natural wobble of the Earth).
How the ILS Started
The idea for the International Latitude Service came from a scientist named Wilhelm Julius Foerster in 1891. He talked about how Seth Carlo Chandler had discovered that the Earth's poles actually move a little bit. This movement affects how we measure latitude.
Because this was so important, the International Geodetic Association decided in 1895 to create the ILS. Its main office was in Potsdam, Germany, and Friedrich Robert Helmert was in charge. Regular observations began in 1899. Even during difficult times, like after 1916, the work continued under a different group led by Raoul Gautier.
The Original Observatories
The International Latitude Service used a network of six special observatories. These observatories were all built very close to the same line of latitude: 39 degrees 08 minutes north. This was important because it helped them compare their measurements easily.
The first six observatories were located in:
- Gaithersburg, Maryland, United States
- Cincinnati, Ohio, United States
- Ukiah, California, United States
- Mizusawa, Iwate, Japan
- Charjui, Turkmenistan
- Carloforte, Italy
How They Studied the Earth's Wobble
To study the Earth's wobble, the observatories looked at specific groups of stars. Each group had six pairs of stars. Every night, each observatory would observe two of these star groups following a set schedule. Then, they would compare their measurements with the data collected by the other observatories. This way, they could see how the Earth's position changed over time.
Changes and Legacy
Over the years, some of the original observatories had to close because of money problems or wars. However, a new station was opened in Uzbekistan after World War I.
The data collected by these observatories over many years is still very useful to scientists today. It has helped them learn more about:
- How the Earth's poles move.
- The physical properties of our planet.
- Changes in climate.
- How GPS and navigation systems work.
The final six observatories that were part of the ILS were:
- Gaithersburg, Maryland, USA, Gaithersburg Latitude Observatory
- Cincinnati, Ohio, USA
- Ukiah, California, USA
- Mizusawa, Japan, National Institutes of Natural Sciences National Astronomical Observatory of Japan, Mizusawa VERA Observatory
- Kitab, in Uzbekistan
- Carloforte, Italy
In 1962, the International Latitude Service was renamed the International Polar Motion Service (IPMS). Later, in 1987, a new organization called the International Earth Rotation Service (IERS) was created and took over the important work of studying the Earth's rotation and wobble.
See also
In Spanish: Servicio internacional de latitud para niños
- List of astronomical observatories
