A multinational team of scientists, led by Patricia Schady, will measure the abundance of heavy elements in galaxies over 10 billion light years away. Here’s more from Astronomy Now:
All elements heavier than hydrogen and helium are known, in astronomer-speak, as ‘metals’. These ‘metals’ are formed by stars, and as each generation of stars comes and goes, the abundance of metals in the Universe increases. Galaxies that existed 10 billion years ago therefore should have much lower metallicities than modern galaxies, but how much lower? Measuring the metallicity of distant galaxies will teach us the rate of star-formation in the early Universe, and when important molecules necessary for rocky planets or life became commonplace. It will also help us understand how our Milky Way has evolved into the galaxy that it is today.
However, measuring the metallicity of galaxies at great distances from us, which we see as they were just three or four billion years into cosmic history, is not easy. There are two ways to do this. One is to search for light emitted at specific wavelengths by various molecules in these galaxies, which is difficult because these emission lines are often very faint. The other way is to look for molecules absorbing light from a bright background object. The wavelength of light that is absorbed depends on the type of molecule doing the absorbing, making these molecules readily identifiable.