GEOMAGNETIC STORM WATCH (G1): Minor G1-class geomagnetic storms are possible on Sept. 23-24 when a fast-moving stream of solar wind is expected to reach Earth. This stream is coming from a canyon-shaped hole in the sun's atmosphere. The Russell-McPherron effect could turn it into a nice display of equinox auroras. Aurora alerts: SMS Text
WE'VE TURNED STARLINK INTO A PLANETARY BAROMETER: 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.
Earth is surrounded by more than 11,000 Starlink satellites. Without exception, they all skim the outermost layers of our atmosphere where air pressure and aerodynamic friction rob them of orbital energy. If they didn't occasionally boost themselves with thrusters, every single Starlink would fall back to Earth.
This means we can use the Starlink megaconstellation as a giant sensor for air pressure and drag. Here's how it works: Every day, the US Space Force publishes fresh orbital elements (also known as "TLEs") for every object in Earth orbit. Buried in each TLE is a drag term. We download those drag terms for 1000 Starlinks and convert them into one easy-to-understand number.
It's right here. From now on, we're going to publish the daily value for Starlink satellite drag. This number is a sensitive indicator of space weather. The envelope of air around our planet expands and contracts in response to solar activity. Big geomagnetic storms puff up the atmosphere, causing sharp spikes in drag.
In this plot of drag for 2026, you can see the correlation with geomagnetic storms:
You can also think of this as a plot of air pressure at 480 km where most Starlinks orbit.
Starlinks aren't the only ones we're tracking. We monitor 3 other independent constellations: Planet Labs' SuperDoves (107), Amazon's Kuiper satellites (391), and Eutelsat's OneWeb satellites (651). These provide a check on the Starlink numbers. The SuperDoves are particularly valuable because they have no thrusters to combat drag, making them exquisitely sensitive.
Thank you, Starlink? Come back tomorrow for the latest drag.
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THE CRYSTAL MOON CUBE: On Aug. 22nd, the students of Earth to Sky Calculus launched a cosmic ray balloon to the stratosphere. This laser-etched Crystal Moon Cube went along for the ride:
You can have it for $119.95. The students are selling this premium K9-crystal cube as a fund-raiser for their cosmic ray ballooning program. It's an authentic representation of the Moon, with all of the craters, mountains and lava plains accurately portrayed.
With your order, you will also receive a unique gift card showing the cube floating at the top of Earth's atmosphere. The interior of the card tells the story of the flight and confirms that this gift has been to the edge of space and back again.
Far Out Gifts: Earth to Sky Store
All sales support hands-on STEM education
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