A strong X-class solar flare early Friday triggered some radio blackouts on the side of the Earth facing the sun, astronomers say.

The X1.4-class event, which lasted nearly two hours, arrived at Earth after erupting from active region of the sun dubbed Region 2035, where a sunspot reached its peak intensity late Thursday EDT, they say.

"Region 2035 is rotating out of view and won't pose any danger for much longer, but could in the immediate future," the U.S. Space Weather Prediction Center said in a post.

X-class flares are considered the most intense of such events, and the accompanying numbers provides a relative strength measurement, with an X2 being twice as strong as an IX, an X3 three times as strong and so on.

Solar flares are created when highly-stressed magnetic field lines rising above the sun's photosphere layer are pushed together and accelerate hot ionized gas, ejecting it into space.

The strongest flare of this year so far was an X4.9 in February, while the most intense flare of the current 11-year solar cycle was an X6.9 in August 2011.

The cycle was thought to have peaked during 2013, but as Friday's flare showed, the sun is not finished with its rumblings just yet.

Some solar flares can result in coronal mass ejections, or CMEs, intense bursts of solar wind and magnetic fields.

A CME did result from Friday's flare but was not aimed directly at Earth, so it did not result in a geomagnetic storm or its often-accompanying aurora borealis, the Northern Lights.

Earth's atmosphere protects humans from a flare's powerful pulses or radiation, but when strong enough flares can disrupt communication and GPS satellites in low Earth orbit.

Friday's X1.3 flare resulted in a temporary blackout of high-frequency radio waves on the side of the Earth facing the sun, mostly over the Pacific Ocean and Eastern Pacific Rim, the SWPC reported.

Flares classified as X-class are not the only types of solar outbursts that can affect the Earth. Our star will erupt with slightly less energetic M-class flares, also capable of generating aurora displays, plus relatively weak storms dubbed C-class.

NASA keeps tabs on solar activity in a number of ways, including orbiting spacecraft like the twin STEREO satellites and the Solar Dynamics Observatory, which captures a video of the X1.3 flare.