Annie Russell Maunder

Northern Irish Solar Physicist Annie Russell Maunder
Credit: Courtesy of Dorrie Giles / RAS

Annie Russell Maunder was born in 1868 in Strabane, County Tyrone, Northern Ireland. Russell won a three year scholarship to study at Girton College, Cambridge University and in 1889, passed her examinations with honors. She was also the top mathematician of her year but didn't receive a degree because university restrictions at the time prevented women from earning degrees. Russell joined the solar department at the Royal Greenwich Observatory in 1891, studying the sun, sunspots, and magnetic storms. [Note: sunspots are those dark spots one can sometimes see when looking at the sun using a solar filter or at a projected image. These spots appear dark because they are cooler than the surrounding material]. The department was led by astronomer Walter Maunder whom Russell married in 1895. After their marriage, Annie was required to leave her position at the Observatory due to restrictions that prevented married women from working in public service. However, Annie continued collaborating with her husband for the next 33 years, traveling with him on solar eclipse expeditions all around the world.

Annie Russell Maunder on an eclipse expedition in Labrador, Newfoundland.
Credit: Alfred Johnson / Annie Maunder's family

Annie developed her own camera to take incredible images of the sun, including the first photographs of streamers from the solar corona (the sun's outermost layer). The corona can only be glimpsed from the Earth during a solar eclipse, so Annie was in a prime position to obtain these photographs. However, most of her photographs were published under her husband's name, as was common for married female scientists at the time.

In 1904, Annie and Walter mapped the positions of sunspots from data that had been collected over numerous solar cycles. [Note: the sun goes through an 11-year cycle, transitioning from a solar minimum with the least amount of sunspots and solar activity to a solar maximum with the most sunspots and greatest solar activity and then back to a solar minimum]. What they found was a pattern that looked like butterfly wings, and this pattern is now known as Maunder's Butterfly Diagram. The butterfly pattern demonstrates that sunspots are usually found at higher (northern hemisphere) or lower (southern hemisphere) latitudes on the sun's surface early in the solar cycle (at solar minimum) but then migrate towards the equator later in the cycle.

Maunder's Butterfly Diagram (top panel).
Credit: NASA MSFC

Annie and Walter also confirmed the work of German astronomer Gustav Spörer, who had realized that throughout the 70 years of the Little Ice Age (1645-1715), there had been little to no solar activity. This period of low solar activity is now known as the Maunder Minimum. From this work came the recognition of a connection between sunspot numbers and Earth's climate.

In 1915, the Royal Astronomical Society finally began admitting female members, and Annie Russell Maunder was among the first. An even greater honor is that a crater on the far-side of the Moon is named after Annie and her husband.