Past just detecting a World, transits allow us to carry out spectroscopy on starlight passing from the World’s ambiance. This suggests we will review its composition—detecting gases like water vapor, methane, carbon dioxide, and most likely even oxygen. Oxygen also can make up a lot of Earth’s oceans by mass. https://oxygenchambers84051.theisblog.com/36268642/5-easy-facts-about-oxygen-chamber-cost-described