NEW DELHI: The Sun emitted a powerful solar flare on Thursday, which affected the top of the Earth's atmosphere, causing a shortwave radio blackout around the Indian Ocean. The blackout might have affected radio communications of aviators and mariners for some time. In the coming days, minor geomagnetic storms are expected to hit the Earth due to storm clouds.
A solar flare is an intense burst of radiation coming from the release of magnetic energy associated with sunspots in the form of an explosion. The explosion emits radiation, containing radio waves, X-rays and gamma rays, across the length and breadth of the universe, hurtling them towards planets, including the Earth. During a solar flare, the highly energetic charged particles are expelled from the Sun at speeds close to that of the speed of light. These rays can disturb the ionosphere region of the Earth, which plays an important role in radio communications, explains Nasa.
According to spaceweather.com, "Sunspot AR2929 erupted on Jan 20th, producing a powerful M5.5-class solar flare. Nasa's Solar Dynamics Observatory recorded the extreme ultraviolet flash. During the flare, a pulse of X-rays ionized the top of Earth's atmosphere, causing a shortwave radio blackout around the Indian Ocean. Aviators, mariners, and ham radio operators in the area may have noticed unusual propagation effects at frequencies below 30 MHz."
The space weather website said, "Newly arriving images from the Solar and Heliospheric Observatory (an European spacecraft) confirm that the explosion also produced a coronal mass ejection (CME). The emerging cloud is just outside the Earth `strike zone'. It is expected to miss our planet, although a glancing blow on January 23-24 has not yet been ruled out."
The solar flare, however, accelerated a blizzard of energetic particles towards Earth. The radiation storm was relatively minor. No satellites were harmed. However, many of the particles were funnelled into Earth's polar regions by the planet's magnetic field, causing a sustained shortwave radio blackout around the Arctic and (especially) Antarctic circles, it said.
Geomagnetic unrest is now possible from January 22 to 24 as a series of coronal mass ejections (CMEs) delivers glancing blows to Earth's magnetic field. Two of the CMEs were hurled into space by M-class flares from departing sunspot AR2929; a third CME just left sunspot AR2933, the space weather website said.
None of the storm clouds will land a direct hit, but their combined effect could spark minor G1-class geomagnetic storms, the website stated.
Last year, the US National Oceanic and Atmospheric Administration's Space Weather Prediction Center had said a strong radio blackout occurred in certain regions around the Atlantic Ocean on July 3. (timesofindia)
