Starlink satellites are becoming a barometer for Earth’s atmosphere

Starlink satellites are usually discussed in terms of what they’re doing to the sky. Astronomer Tony Phillips has found a way to use them to learn something about it.Phillips, who runs SpaceWeather.com, has turned the orbital data of hundreds of Starlink satellites into a daily measure of changes in Earth’s upper atmosphere. He calls it a "planetary barometer," though it tracks air density rather than pressure. His planetary barometer relies on an ingenious observation, which Phillips explained in a blog…