Earth Hit by Solar Eruption That Could Have Disrupted Satellites

Earth was in the path of an eruption of solar energy on Monday morning which may have caused auroras to be visible in northern U.S. states.

On Sunday, the U.S. National Oceanic and Atmospheric Administration's Space Weather Prediction Center (SWPC) warned of incoming space weather effects that would last until 7 a.m. ET on Monday.

The SWPC said in a warning that was valid until about 2 a.m. on Monday that it was anticipating a geomagnetic K-index level of 5 and that a lower K-index of 4 was expected until 7 a.m. The K-index is a scale used to measure the magnitude of geomagnetic storms. The SWPC releases alerts if it anticipates a K-index measurement of 4 or above.

A K-index of 9 would signify the most extreme geomagnetic storm, which could cause power grid systems to collapse, radio and satellite navigation services to be disrupted for days and auroras to be visible in locations in low latitudes such as Florida and southern Texas.

While Monday's space weather effects were therefore mild, SWPC still warned of some potential impacts, including weak power grid fluctuations in areas north of around 60 to 65 degrees latitude and the potential for auroras to be visible in northern Michigan and Maine. It also said that there could have been a "minor impact on satellite operations."

The K-index is used as a reference for the G-scale, which is another measure of the strength of geomagnetic storms. The G-scale goes from G1 to G5 and starts at K-indexes of 5 or above; a K-index of 5 is equal to G1, for example.

The geomagnetic effects are reported to have been caused by a burst of plasma from the sun called a coronal mass ejection (CME) according to SpaceWeather.com.

Miho Janvier, a space physicist at the Institut d'Astrophysique Spatiale in France, told Newsweek that CMEs are "very common" occurrences—though they don't always target Earth.

"What we know is that the number of CMEs being released by the sun approximately follows the solar cycle, [which lasts] 11 to 13 years on average," she said.

"Their number can be down to zero during the solar cycle minimum for days and weeks, while we can witness a few of them in the same day, and regularly so, at the peak and decaying phase of the cycle.

"As we are now in the ascending phase of a new cycle, we are expecting more solar activity, and therefore more CMEs to be launched from our parent star. I'd certainly say it's an exciting time ahead for some researchers like me who are interested in probing these 'solar storms.'"

The sun
An eruption of solar material can be seen on the right of this image of the sun from NASA's Solar Dynamics Observatory in June, 2011. Solar eruptions called coronal mass ejections are quite common and can cause disruption if they hit earth. NASA/Goddard Space Flight Center/Science Visualization Studio/SDO