A scientist working at the Carnegie Institution's Mount Wilson Solar Observatory near Pasadena, California, produced the first empirical proof of a magnetic field beyond Earth by studying light from a sunspot. He found that the spectral lines in the sunspot's spectrum were splitting apart, a signature of the Zeeman effect, in which a magnetic field separates the energy levels of charged particles that would otherwise sit in the same degenerate electromagnetic state, some aligned with the field and some not, causing their emitted spectral lines to split.
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The hosts mention having seen the original spectrograph plate from this discovery in person at Mount Wilson.
240 words · auto-generated from the episode video
34:29working at Mount Wilson Solar Observatory, which was established by the Carnegie Institution near Pasadena, California. And he discovered the first empirical proof of extraterrestrial magnetic fields. What he did was look at the spectra that was coming out of a sunspot on the sun and there you can see that the spectral lines were splitting. This is due to the zemen effect which happens when you have um charged particles that are emitting spectral lines that have degenerate electromagnetic states in a magnetic field like some are aligned some are not aligned. So you have a separation of energy levels. That's the famous um spectrograph that actually we saw in
35:10person when we were there and I remember seeing it. I remember seeing that exact you know plate going holy >> you know what this is a familyfriendly podcast. We are moving on to 1909 precise measurement of the elementary the excuse me the precise measurement of the elementary electrical charge. That's right. So JJ Thompson back in England had discovered the electron but he had only discovered the charge to mass ratio of the electron and he had shown that it's massive. This is a single particle that holds a lot of charge but we don't know what the actual charge is. We only know the ratio. Robert Milikin along
35:50with his graduate student Harvey Fletcher precisely measured that at the University of Chicago using the oil drop