Earth will not keep its oxygen-rich atmosphere forever, NASA says. 🌍🫁 A NASA study in Nature Geoscience projects atmospheric oxygen will fall below 10% of today’s level in a little more than a billion years. As the Sun brightens, Earth’s carbon cycle will leave plants with less carbon dioxide for photosynthesis, reducing the process that replenishes oxygen. The finding also means oxygen may signal life on distant planets for only part of their habitable history. #NASA #Earth #Oxygen #Astrobiology #SpaceScience