Astronomers are mapping the Milky Way using the 22 meter Mopra Telescope in Australia along with telescopes in Antarctica and Chile. They are particularly mapping the location of our galaxy’s galactic clouds, which can be up to 100 light years across. Galactic clouds are relatively easy to see and made up of carbon monoxide, the second most abundant molecule in space. But “dark” galactic gas clouds are not so easy to see. Astronomers believe they are made up of molecular hydrogen, which is too cold to detect. They say the surveys from the three telescopes will provide a picture of the distribution and movement of gas clouds in the galaxy.