Monday, January 25, 2010

Plant analogies for nebulae and star clusters

In communicating astronomy we often use terms such as "birth" and "death" of stars. Other than that, we have a mechanistic way of looking at the universe. But I like the William Herschel thought of the universe: as a garden, with nebulae and star clusters, in effect, as 'species of plants at various stages of growth and decay. I ran into this while reading the fascinating Richard Holmes book, The Age of Wonder: How the Romantic Generation Discovered the Beauty and Terror of Science (please read it if you have time. It is fantastically written and quite deservedly was on almost all the lists of best non-fiction books of 2010). Here is the relevant paragraph from the Holmes book (the Herschel quotes are from his 1789 paper, Catalogue of Second Thousand Nebulae with Remarks on the Construction of the Heavens):
This method of viewing the galaxies...presented the entire universe in a new kind of light, with the most radical implications. 'The heavens are now seen to resemble a luxuriant garden which contains the greatest variety of productions, in different flourishing beds...and we can extend the range of our experience [of them] to an immense duration.' In a garden we may live 'successively to witness the germination, blooming, foliage, fecundity, withering, and corruption of a plant'. Just so, the universe presented 'a vast number of specimens, selected from every stage through which the plant passes in the course of its existence,' but brought 'at once to our eyes', and viewed at one particular moment from the earth.
Very nice analogy. But Holmes points to a larger implication: that "astronomy changed decisively from a mathematical science concerned primarily (for practical purposes) with navigation, to a cosmological science concerned with the evolution of the stars and origins of the universe." A few years later (in 1796) Laplace would solidify the latter view with the publication of his nebular hypothesis of solar system formation. Fascinating time!

While we are at it, here is a portion of Joseph Haydn's oratorio, The Creation. Hayden claimed that a visit to Herschel's home and observatory helped him compose the oratorio. Here is The Creation with the London Symphony Orchestra:

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