Friday, April 20, 2012

William Herschel

William Herschel was born in Germany in 1738 but spent most of his eighty-three years in England. He is best remembered for discovering the planet Uranus, and the symbol for the planet contains a letter “H” in his honor. This discovery was only one of his many accomplishments.

Herschel also discovered two moons orbiting Uranus and two moons orbiting Saturn. He discovered more than 800 binary stars, which are pairs of stars that are very close together and orbit each other. He was the first to guess that such stars are bound to each other by gravity. In addition, he found over 2400 groups of stars, some of which later turned out to be galaxies.

Herschel was the first to see that the ice caps on Mars expand and shrink, proving that Mars has seasons. He also measured the tilt of the axis of Mars. He realized that our sun and its planets are moving together and figured out the direction we are traveling. He studied our galaxy and correctly concluded that it is shaped like a disk that is much wider than it is thick.

Herschel sometimes surprised himself with his discoveries. One day in 1800, while he was studying sun spots, he separated sunlight into its colors with a prism and, using a thermometer, found that beyond the red band of light there was a great deal of heat but no visible light. He had discovered infrared light, a kind of light that is invisible to humans.

Some of Herschel’s ideas were not fully developed. For example, he guessed that by studying changes in the price of wheat over time, he could make conclusions about changes in the weather and the sun’s activity. Years later, other scientists found out that his theory works, but Herschel did not have enough information, during his lifetime, to carry out accurate research. He also coined the word asteroid, but did not use it exactly the way that scientists do today. Some of his ideas were wrong and even silly, although many people who lived at the same time did not think they were silly. For example, he thought that every planet and star, including our sun, is inhabited. He even guessed that the people who live on the sun would have giant heads.

In his scientific work, Herschel did not limit himself to astronomy. He was as fascinated by microscopes as telescope, and he built both. By looking at corals under one of his microscopes, he discovered that they are animals rather than plants, as most people thought at the time. In this way, he made a contribution to biology. His talents were not even limited to science. Herschel could play the violin, cello, harpsichord, oboe and organ, and he composed twenty-four symphonies as well as other musical compositions.

The rest of Herschel’s family was also gifted in music and science. His father and brother were musicians, and his sister, Caroline, and son, John, were scientists. Caroline discovered several comets and updated a book on stars for which she was honored by the Royal Astronomical Society. John discovered more than one thousand objects in the night sky and gave names to the moons of Saturn and Uranus, some of which were discovered by his father. John also contributed to our knowledge about mathematics, chemistry, photography, ultraviolet light and color blindness.