Friedrich Bessel facts for kids
Quick facts for kids
Friedrich Bessel
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C. A. Jensen, Friedrich Wilhelm Bessel, 1839 (Ny Carlsberg Glyptotek)
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| Born | 22 July 1784 Minden, Kingdom of Prussia
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| Died | 17 March 1846 (aged 61) Königsberg, Prussia
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| Nationality | German |
| Known for | Bessel functions Bessel ellipsoid Besselian elements Bessel's correction Bessel's inequality Repsold–Bessel pendulum |
| Awards | PhD (Hon) University of Göttingen (1811) Honorary member of the Saint Petersburg Academy of Sciences(1814) Lalande Prize (1811), (1816) Gold Medal of the Royal Astronomical Society (1829 and 1841) |
| Scientific career | |
| Fields | Astronomy, mathematics, geodesy |
| Institutions | University of Königsberg |
| Doctoral students | Friedrich Wilhelm Argelander Heinrich Scherk |
Friedrich Wilhelm Bessel (German: [ˈbɛsl̩]; 22 July 1784 – 17 March 1846) was a brilliant German scientist. He was an astronomer, mathematician, physicist, and expert in measuring the Earth's shape (a geodesist). Bessel was the first astronomer to accurately measure the distance from the Sun to another star. He did this using a clever method called stellar parallax. Some important mathematical tools, called Bessel functions, are named after him. These functions are used in many areas of science today.
Contents
Early Life and Education
Friedrich Bessel was born in Minden, a city in what was then Westphalia, Germany. He was the second son in a large family. At just 14 years old, he left school because he didn't enjoy learning Latin. Instead, he started an apprenticeship at a company in Bremen that imported and exported goods.
This job involved a lot of shipping, which made him interested in mathematics. He used his math skills to solve problems related to navigation. This interest soon led him to astronomy, as knowing the positions of stars was key to figuring out a ship's longitude (its east-west position).
Becoming an Astronomer
Bessel's talent for astronomy was noticed by Heinrich Wilhelm Olbers. Olbers was a doctor in Bremen and a well-known astronomer. In 1804, Bessel improved the calculations for the orbit of Halley's Comet. He used old observations from the year 1607. This work was so good that it was published in a famous astronomy journal.
In 1806, after finishing his business training, Bessel left his job. He became an assistant at Johann Hieronymus Schröter's private observatory in Lilienthal. There, he carefully studied old star observations made by James Bradley. Bessel used this data to figure out the exact positions of more than 3,200 stars.
Director of Königsberg Observatory
Even though Bessel had not gone to university, he was appointed director of the new Königsberg Observatory in January 1810. He was only 25 years old! He stayed in this important role until he passed away.
Some university professors questioned his right to teach math because he didn't have a university degree. So, Bessel asked his friend, the famous mathematician Carl Friedrich Gauss, for help. Gauss arranged for Bessel to receive an honorary doctor's degree from the University of Göttingen in 1811. Bessel and Gauss wrote letters to each other for many years, sharing their scientific ideas.
In 1842, Bessel traveled to Manchester, England. He attended a meeting of the British Association for the Advancement of Science. There, he gave a presentation about astronomical clocks.
Family Life
Bessel married Johanna Hagen. Her father was a chemist. Bessel had two sons and three daughters. Sadly, both of his sons died young. His eldest daughter, Marie, married a physicist named Georg Adolf Erman. Their son, Adolf Erman, became a famous expert in ancient Egypt.
Bessel passed away in March 1846 at his observatory after being ill for several months.
Major Scientific Work
Bessel made many important discoveries and contributions to science.
Mapping the Stars
While the Königsberg Observatory was still being built, Bessel worked on a major book called Fundamenta Astronomiae. This book was based on James Bradley's observations. As part of this work, Bessel created tables that helped correct for how Earth's atmosphere bends starlight. This work earned him the Lalande Prize in 1811. The Königsberg Observatory officially opened in 1813.
Starting in 1819, Bessel used a special telescope called a meridian circle to measure the positions of over 50,000 stars. He was helped by his skilled students, including Friedrich Wilhelm Argelander.
Measuring Star Distances
Bessel is most famous for being the first to accurately measure the distance to a star. Astronomers had long believed that a method called stellar parallax could do this. Parallax is the apparent shift in a star's position when viewed from different points in Earth's orbit around the Sun.
In 1838, Bessel announced that the star 61 Cygni had a parallax of 0.314 arcseconds. This measurement showed that the star was about 10.3 light-years away from Earth. Today, we know the distance is closer to 11.4 light-years, so Bessel's measurement was very close! This was a huge step forward. It proved that the Earth moves around the Sun and greatly expanded our understanding of the universe. Soon after, other astronomers also measured the distances to stars like Vega and Alpha Centauri.
Discovering Hidden Companions
Bessel's very precise measurements also helped him notice tiny wobbles in the movements of the bright stars Sirius and Procyon. He figured out that these wobbles must be caused by the gravity of unseen companion stars pulling on them.
In 1844, he announced the existence of Sirius's "dark companion." This was the first time someone correctly predicted an unseen star based only on its gravitational effect. This prediction later led to the discovery of Sirius B, a type of star called a white dwarf.
Understanding Measurement Errors
Bessel was the first scientist to understand something called the personal equation. He realized that when several people observe the same event at the same time, like a star crossing a line in a telescope, they might record slightly different times. This showed that human observation can have small, personal differences.
Predicting Eclipses
In 1824, Bessel created a new way to calculate the details of eclipses. His method used what are now called Besselian elements. This method made eclipse calculations much simpler and more accurate. It is still used by astronomers today!
Star Charts and Neptune
In 1825, Bessel suggested that the Prussian Academy of Sciences should start creating new star charts. This became an international project. One of these new charts helped astronomer Johann Gottfried Galle find the planet Neptune in 1846. Galle found Neptune very close to the position that another scientist, Urbain Le Verrier, had calculated.
Bessel Functions
In the early 1800s, while studying how gravity affects multiple objects, Bessel developed special mathematical tools. These are now known as Bessel functions. They are very important for solving certain types of equations and are used in many areas of classical physics and quantum physics.
Contributions to Geodesy
Like many astronomers of his time, Bessel also worked in geodesy, the science of measuring and mapping the Earth. He developed a method for solving a key problem in geodesy.
In 1830, he was asked by the king to survey East Prussia. The goal was to connect the existing Prussian and Russian measurement networks. He worked with Johann Jacob Baeyer on this project. Bessel also made a more accurate estimate of the Earth's shape, which is now called the Bessel ellipsoid.
Honors and Awards
Friedrich Bessel received many awards and honors for his important work:
- He received an honorary doctor's degree from the University of Göttingen in 1811.
- He won the Lalande Prize from the French Academy of Sciences twice, in 1811 and 1816.
- He became a member of the Prussian Academy of Sciences in 1812.
- He was elected a Fellow of the Royal Society in 1825.
- He won the Gold Medal of the Royal Astronomical Society twice, in 1829 and 1841.
Bessel was also one of the first members of the Order Pour le Merite (Civil class) when it was created in 1842.
Legacy
Several things in space and on Earth are named after Friedrich Bessel:
- The largest crater in the Moon's Mare Serenitatis is named after him.
- The asteroid 1552 Bessel was named in 1938, 100 years after he measured the first stellar parallax.
- Two fjords (long, narrow inlets of the sea) in Greenland are named Bessel Fjord.
See also
In Spanish: Friedrich Bessel para niños
- List of things named after Friedrich Bessel
Images for kids
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Königsberg Observatory in 1830. It was destroyed in the Second World War.
