Why Some of the Rainbow Is Missing
If you look closely at a rainbow made from sunlight (e.g. through a prism or an actual rainbow), you’ll notice that some of the colors are missing. It turns out that these absent colors (called Fraunhofer lines) have something to do with the types of elements that are present in the Sun (and the Earth’s atmosphere). Dr. Joe Hanson explains in the video above.
Over 200 years ago, scientists were looking at sunlight through a prism when they noticed that part of the rainbow was missing. There were dark lines where there should have been colors. Since then, scientists have unlocked the secrets encoded in these lines, using it to uncover mind-boggling facts about the fundamental nature of our universe and about worlds light-years away.
Science is fascinating…Fraunhofer lines can tell us something about objects and processes all along the Powers of Ten scale, from the inner workings of the atom to the composition of the Earth’s atmosphere to how quickly the universe is expanding or contracting.
If you’d like to check out the missing parts of the rainbow for yourself, you can make this DIY spectroscope using a CD or DVD and a few other items. (via the kid should see this)
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