Sun Hurls Coronal Mass Ejection Toward Earth and Spacecraft

The sun may be approaching the peak of its 11-year solar cycle, but so far its activity has been relatively disappointing. Now, though, the sun has made its move; our nearest star hurled an Earth-directed coronal mass ejection (CME) toward our planet early on Tuesday morning.

CMEs are solar phenomena that can send billions of tons of particles speeding into space. When directed toward the Earth, they can reach our planet one to three days later. While these particles can't travel through the atmosphere to harm humans on Earth, though, they can affect electronic systems in satellites and on the ground.

In this case, the CME left the sun at speeds of about 560 miles per second; that's fairly typical for most CMEs. Whether this particular incident will affect Earth to any great extent, though, remains to be seen. Yet it could possibly cause something called a geomagnetic storm.

Geomagnetic storms occur when Earth-directed CMEs funnel energy into Earth's magnetic envelop, called the magnetosphere, for an extended period of time. The CME's magnetic fields peel back the outermost layers of Earth's fields and change their very shape. These magnetic storms can degrade communication signals and caused unexpected electrical surges in power grids. In addition, they can spur the aurora, causing it to light up brilliantly in the sky in a spectacular display.

These storms aren't all that frequent during a solar minimum. Yet in this case, our sun is ramping up to hit its solar peak later in 2013. This means that it's very possible that a large storm could occur. That said, this particular solar maximum has been weak so far--a fact that's not entirely surprising. In 2009, researchers at NASA predicted that the solar cycle this year would be relatively mild. In fact, they believed that the number of sunspots would be the lowest since 1928.  

Since this CME will possibly pass by the Messenger and Juno spacecraft, mission operators are ready to put the spacecraft into safe mode to prevent their instruments from being harmed by the solar material.

Want to learn more about space weather? Check out NOAA's Space Weather Prediction Center here.