Alexander Wilson (astronomer)

Alexander Wilson (1714 – 1786) was a Scottish astronomer, mathematician, and typefounder who made significant contributions to the field of astronomy. He is best known for his observations of sunspots and the atmosphere of the Sun, as well as for being the founder of Wilson's theorem in mathematics.

Early Life

Alexander Wilson was born in 1714 in St Andrews, Scotland. He was initially apprenticed as a typefounder, following in the footsteps of his father, who was also involved in the trade. However, Wilson's interests soon shifted towards mathematics and astronomy, fields in which he was largely self-taught.

Career

Wilson's career in astronomy began in earnest when he was appointed the first Regius Professor of Astronomy at the University of Glasgow in 1760. This position allowed him to focus on his research interests, particularly in observing and understanding the Sun.

Contributions to Astronomy

Wilson's most notable contribution to astronomy was his study of sunspots. In 1769, he published observations that led to the understanding that sunspots were depressions in the Sun's surface, rather than simply small planets or moons passing in front of it, as was previously thought. This was based on his observation of the changing shape of sunspots as they moved across the Sun's disk, which he correctly interpreted as the result of the sunspots being cavities with sloping sides.

He also proposed the Wilson effect, which describes the appearance of sunspots when observed near the edge of the Sun's disk. According to this effect, sunspots appear to be depressions on the solar surface because the penumbra (the lighter area surrounding the darker core of the sunspot) appears wider on the side closest to the center of the Sun and narrower on the side away from the center.

In addition to his work on sunspots, Wilson made contributions to the study of the atmosphere of the Sun. He was among the first to suggest that the Sun had an atmosphere, an idea that was revolutionary at the time.

Legacy

Alexander Wilson's work laid the foundation for future studies of the Sun and solar phenomena. His observations and theories significantly advanced the understanding of sunspots and the solar atmosphere, contributing to the development of solar physics as a scientific discipline.

Wilson's contributions to mathematics, particularly Wilson's theorem, which states that a natural number n > 1 is a prime number if and only if (n-1)! + 1 is divisible by n, also remain a significant part of his legacy.

Death

Alexander Wilson passed away in 1786 in Glasgow, Scotland. His work continued to influence the fields of astronomy and mathematics long after his death.