Washington  - The sun has emitted a huge solar flare that caused a radio blackout on Earth. The solar flare erupted from an active sunspot region known as Region 2035 located on the far western side (or limb) of the sun as seen from Earth.

The flare sparked a high-frequency radio blackout for about an hour on the daytime side of Earth, most likely over the Pacific Ocean and Eastern Pacific Rim, according to space weather experts.

‘Region 2035 is rotating out of view and won’t pose any danger for much longer, but could in the immediate future,’ SWPC officials wrote in the update. When aimed directly at Earth, X-class solar flares can endanger astronauts in space, as well as interfere with communications and navigation satellites in orbit.

The most powerful X-class flares can also affect power grids and other infrastructure on the Earth. Thursday’s solar flare was the fourth X-class solar flare of 2014. Peaking at 8:27 p.m. EDT on April 24, it is classified as an X1.4 flare. X-class denotes the most intense flares, while the number provides more information about its strength. An X2 is twice as intense as an X1, an X3 is three times as intense.

It followed an X1.2 solar flare on Jan. 7, a monster X4.9 solar flare on Feb. 24, as well as an X1 solar flare on March 29. While X-class flares are the most powerful eruptions on the sun, the star also experiences more moderate M-class solar flares (which can supercharge Earth’s aurora displays) and weaker C-class storms.

The sun is currently in an active phase of its 11-year weather cycle, and was expected to reach its peak activity in 2013. Images of the flare were captured by NASA’s Solar Dynamics Observatory. A solar flare occurs when magnetic energy that has built up in the solar atmosphere is suddenly released.

Radiation is emitted across virtually the entire electromagnetic spectrum, from radio waves at the long wavelength end, through optical emission to X-rays and gamma rays at the short wavelength end. The amount of energy released is the equivalent of millions of 100-megaton hydrogen bombs exploding at the same time. A flare occurs when magnetic energy that has built up in the solar atmosphere is suddenly released - mostly in the active regions around sunspots.

Their frequency varies from several a day, when the sun is particularly active, to less than one a week during quiet periods. Earlier this year on On March 29, the sun unleashed a massive X-class solar flare causing a brief radio disturbance while generating a series of coronal mass ejections (CMEs).

CMEs are powerful plasma eruptions near the surface of the sun driven by kinks in the solar magnetic field.

Earlier this month, scientists came a step closer to understanding this powerful phenomenon behind solar flares by witnessing, for the first time, the mechanism behind it. Footage put together by an international team led by University of Cambridge researchers showed entangled magnetic field lines looping from the sun’s surface.

These magnetic lines slip around each other and lead to an eruption 35 times the size of the Earth and an explosive release of magnetic energy into space.

The discoveries of a gigantic energy build-up have brought scientists a step closer to predicting when and where large flares will occur. ‘We care about this as during flares we can have CMEs and sometimes they are sent in our direction,’ said lead author, Dr Jaroslav Dudik from Cambridge University.

‘Human civilisation is nowadays maintained by technology and that technology is vulnerable to space weather.’ ‘Indeed, coronal mass ejections can damage satellites and therefore have an enormous financial cost.’ ‘They can also threaten airlines by disturbing the Earth’s magnetic field. ‘Very large flares can even create currents within electricity grids and knock out energy supplies.’