Astronomer watches Starlink satellites sinking to build a 'planetary barometer'

The atmosphere expands and contracts; watching objects in orbit reveals the extent

Simon Sharwood Simon Sharwood APAC Editor Published fri 25 Sep 2026 // 05:46 UTC

Phillips runs spaceweather.com, which tracks solar flares, the solar wind, shifts in Earth’s geomagnetic field, and other phenomena.

On Tuesday, he published an article that opens “Starlink has many downsides.”

“The megaconstellation interferes with astronomy, pollutes the atmosphere with metallic re-entry debris, and has pushed Low Earth Orbit to the brink of the Kessler Syndrome.”

“On the other hand, it makes a terrific barometer.”

That’s because Earth’s atmosphere expand when it heats, often in response to increased radiation increases. Most satellites lose a few meters of altitude every day and when the atmosphere expands the rate at which their orbits decay can accelerate.

Phillips points out that the US Space Force tracks all artificial satellites and publishes data called “TLEs” about their orbits.