¡SkyCaramba! Weekly astronomy blog for the week ending August 22, 2015
Just as science learned to make bigger and better magnifying lenses for telescopes, science also learned to make bigger and better prisms and diffracting glasses for breaking light into its component colors. And just as better telescopes revealed more detail in the things above, better prisms and diffracting glasses revealed more too.
When you see a rainbow, you see all the colors present in sunlight. For convenience, we say all the colors that can exist are present: red, orange, yellow, green, blue, and purple. But in the 1850s, scientists using the best diffracting glasses and prisms of the time noticed some dark lines in it. The spectrum also had dark lines when they shined light through various gases. The gases were absorbing those wavelengths. Scientists found that they could identify gases by where the dark lines were.
Scientists also found that light from the atmosphere around the sun has an opposite appearance. The light from it appears in narrow wavelengths, and the rest of the spectrum is dark. Noting the placement of these emission lines also turned out to be a very useful way of identifying gases.
Soon, scientists ...