Video: The Impossible Element Hiding in the Sun
By: SciShow Space
The first periodic table didn’t include space for the noble gases – since they don’t react with anything they’re very hard to detect through chemistry.
Helium was discovered in space due to a solar eclipse in the 1860s before it was discovered on Earth in 1895 through radioactive decay of Uranium.
By looking at light through a prism, scientists discovered that you can distinguish different types of light by looking at its spectrum.
Light generated by burning different element has a unique collection of dark lines. This is due to each element absorbing light at specific wavelengths. This is governed by quantum mechanics. Atoms absorb photons at different wavelengths, and this behavior is unique to each element.
The solar eclipse allowed scientists to get a spectrum that included Helium from the Sun’s corona by blocking out the main spectrum.
We use spectroscopy to learn about composition of all kinds of things that emit or reflect light. We can even study the atmospheres of planets orbiting other stars.