## Partially Attended

an irregularly updated blog by Ian Mulvany

# Robert Bunsen's Birthday

#### Thu Mar 31, 2011

##### 367 Words

Google’s homepage cartoon today tells me that it’s Robert Bunsen’s birthday. He is famous for the invention of the burner named after him, but his contribution to our understanding of the universe around us runs much much deeper than that. He co-created the science of spectroscopy with Gustav Kirchhoff. This is something I learned about when I was living for a while in Heidelberg, one of the university building’s along the Hauptstrasse is named after Bunsen.

The invention of spectroscopy was a huge step in unlocking the structure of the universe at the largest and smallest scales. It led to the experiments that laid the foundation of atomic theory. It enabled us to see what the stars are made from. Before spectroscopy we could see the stars, but in a way, after it we were able to taste them, to understand their properties and compositions.

The philosopher Aguste Compte wrote in 1835 that:

On the subject of stars, all investigations which are not ultimately reducible to simple visual observations are…necessarily denied to us… We shall never be able by any means to study their chemical composition.

It was spectroscopy that blew away that limit. Spectroscopy is the science that is used to determine the red-shift of galaxies, and so it is also used to measure the extent of the wider universe. It turned light from a pure substance to a code of substances.

I often wonder now about the limits of knowledge, about whether we can ever understand experience in an analytic way, whether the Hubble horizon of the visible universe shields from us strangeness that we can never know about, whether as we look at the universe on smaller and smaller scales information truly becomes the only thing of matter, whether the complexity expressed in every simple act in the changing of the seasons is a complexity too much for us to bear.

I’m often tempted to side with the view of there being ultimate unknowables. And then I think a little about spectroscopy, and how such a simple change in our point of view changed so much of what we could view and understand, and I hold back a little more.

Happy birthday Robert Bunsen!