Spotlight: Geomagnetic Storm Creates Bright Northern Lights While Also Affecting NIST’s Cesium Clocks

Did you see the northern lights recently? NIST’s cesium fountain clocks did.

Coronal mass ejections on the Sun sent waves of highly energized particles crashing into the Earth’s atmosphere over the weekend of May 10. This geomagnetic storm created the bright aurora borealis that was seen across all 50 United States, including Hawai‘i, according to NOAA’s Space Weather Prediction Center. NOAA rated this storm a G5, the strongest on its scale. 

Storms of this magnitude interfere with the Earth’s magnetic field. The storm was so intense that NIST’s cesium fountain clocks, NIST-F3 and F4, directly sensed the variation of 0.1% in Earth’s magnetic field due to the storm. That was surprising — both clocks have layers of magnetic shielding to block out environmental effects like geomagnetic storms. 

But don’t worry, NIST is well prepared for these events and applied a correction to the clocks to compensate, so we could keep civilian time ticking without interruption.