Friedrich Bessel
Friedrich Bessel was born in 1784 in Germany. He stayed in Germany his whole life and did not move around much. When he was young, he did not seem to advance in any subjects in school. He was not very good at Latin, but he taught it to himself when he was older. For this reason, people believe that he was simply not inspired or interested in the language. He was obviously gifted, because he earned a doctorate without attending a university.
Bessel started working at an import-export firm at the age of 14, where he first became interested in navigation, leading to his interest in astronomy and mathematics. After publishing his first paper on Halley’s Comet in 1804, most of his work seemed to focus on astronomy. A few years later, he got a job at an observatory in Konigsberg, where he spent much of his life. There, he used astronomer James Bradley’s observations as a data base, but in order to do so he had to fix any errors in Bradley’s measurements. Although he earned less at the observatory, he preferred working there so that he could gain a better understanding of the sky. For a brief period of his life, Bessel worked at another observatory assisting Johann Schroter.
His study of celestial mechanics eventually allowed him to use the effect of parallax to calculate the distance to the star 61 Cygni. In 1838, the Royal Astronomical Society rewarded him with a gold medal for his results. Compared to today’s accepted value, he was only off by about two one-hundredths of a degree. Of course, Bessel’s accomplishments earned him other awards and titles, such as the Lalande Prize from the Institut de France, another from the Berlin Academy, and a position as a Fellow of the Royal Society. He was highly respected and popular around the world, since he spent his whole adult life helping the world understand astronomy and mathematics.
Most likely Bessel’s most memorable accomplishment is what is now known as the Bessel functions. This is a series of functions derived by Bessel that are all related to the perturbation of the planets in our solar system. These equations are still used in mathematics, physics, and engineering. Another helpful publication of his was Fundamenta Astronomiae in 1818. The book was a catalogue of over 3,000 stars. He continued working on this until he had about 63,000 stars catalogued in 1833.
Many other astronomers and mathematicians used his discoveries to make intriguing discoveries of their own. One astronomer, named Walter Adams, calculated the size and mass of a distant star, and, thanks to Bessel’s work, found that this star was so much denser than our sun that a thimbleful of the star’s mass would weigh about ten tons here on Earth.
A major issue during his lifetime was the possibility of life on other planets in our solar system. He did not believe it was possible, other than perhaps on Mars. He also observed the lack of an atmosphere on the moon. This is something he wrote on the subject: “The moon is decisively different from the earth in the primary point of an atmosphere; the sun is of an entirely different nature; for Mercury and Venus we have found no basis for assuming a similarity; Mars appears to possess an atmosphere and summer and winter, even snow and ice; ... Jupiter and Saturn are very dissimilar to the earth...”
A few other contributions Bessel made include a correction to the seconds pendulum (a pendulum that had a period of exactly one second) and his calculation of the eccentricity of the Earth. He came up with an eccentricity of about 1/299. Today’s accepted value is approximately 1/298.3. Another interesting fact about Friedrich Bessel is that even without having been to college himself, he was a very well known university professor. He died in 1846, after a life of respect and praise.
