History and Science: Sunspots

by Cliopatria

It's easy to forget how long people have been doing science. For example, we have decent sunspot data going back at least four hundred years:

Of course, people didn't really know what sunspots were until quite recently, and I don't think we're quite sure of their function/role in stellar development quite yet, but we do have a much better sense of what they are and what they do. And it matters: as the article points out, sunspots and other solar activity sends radiation and ionization through the whole solar system, affecting communications and, for those select few, travel.

The article isn't about history of science, except insofar as it's about the refinement of the 11-year sun cycle theory. But the chart caught my eye (particularly that late 17c lull).

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Jason T. Kuznicki - 10/28/2004

As I recall, there were those who doubted Galileo's observations during the late seventeenth century: They just didn't see the spots that Galileo reported, even when they looked for them. Whether this is a question of poor equipment, or observational error, or a genuine absence of sunspots at that time--I'm really not sure. Someone more expert in the history of science could probably give a better answer.

Richard Henry Morgan - 10/27/2004

There are some gaps in the solar observations, and researchers have used proxies to reconstruct the history, based on measures highly correlated with solar activity (like Carbon 14 ratios in tree rings). There's a good brief article on this available through the Harvard Magazine website.

Oscar Chamberlain - 10/27/2004

One of the problems in the research over global warming has concerned the constancy of energy from the sun. Another is the comparatively short time frame in which sunspots have been observed.

Even within the period from Galileo to the present, there are questions. For example, how many observations were made in the late 1600s. I would assume the observations are frequent enough to support conjecture over the mini-Ice Age but I do not know.

Jonathan Dresner - 10/27/2004

I did think of the little ice age, but I didn't know that anyone had actually made that connection. Thanks.

Richard Henry Morgan - 10/27/2004

There is some interesting work by Sallie Baliunas, of the Harvard-Smithsonian Center for Astrophysics, on the relation between sunspots and global warming. She's not exactly a slouch -- she won the Bok Prize in Astronomy, and is deputy director of the Mt. Wilson Observatory. You will note that the low activity of the 1600's coincides with the Little Ice Age. Maybe as much as 40% of global warming may be atributed to the sun, it has been proposed. Interesting stuff.