April 1, 2014
This past weekend, the Sun produced the X1-class solar flare that caused short radio blackout on Earth. Tomorrow, we could also notice amplified northern and southern lights.
X1 solar flare captured by NASA's Solar Dynamics Observatory. Credit: NASA/SDO
Our Sun has a habit of releasing solar flares that are basically energy in form of electrons, ions and atoms. Sometimes they hit Earth, which protects us from solar flares with its atmosphere and magnetic field. These flares are classified by their strength - A, B, C, M, X and Z, with type A being the least powerful and type Z being the most powerful kind. They occur in regions around sunspots.
One such X1-class sunspot, called AR2017, is dissipating, but is still producing solar flares like one that hit Earth last weekend. This caused radio blackout for a couple of minutes on Earth, but it also created radio signals, manifested by static on radio receivers.
"Solar flares are powerful bursts of radiation," says Karen Fox of NASA's Goddard Space Flight Center. "Harmful radiation from a flare cannot pass through Earth's atmosphere to physically affect humans on the ground, however — when intense enough — they can disturb the atmosphere in the layer where GPS and communications signals travel."
When solar flares hit Earth's atmosphere, their particles are directed by our planet's magnetic field to northern and southern regions where they create northern and southern lights, respectively. Tomorrow, April 2, northern and southern lights might get amplified by a minor geomagnetic storm caused by this X1-class flare and coronal mass ejections that recently occurred.
"The explosion above sunspot AR2017 sent shock waves racing through the sun's atmosphere at speeds as high as 4800 km/s (11 million mph)," said astronomer Dr. Tony Phillips of spaceweather.com. "Radio emissions stimulated by those shocks crossed the 93 million mile [149 million kilometres] divide to Earth, causing shortwave radio receivers to roar with static."
The recent X1-class flare was observed by The National Oceanic and Atmospheric Administration (NOAA) Space Weather Prediction Center. Space weather is increasingly important field of study, since it not only affects communication on Earth, but its negative effects can be hazardous to astronauts in Earth's orbit. As opposed to putting astronauts in glorified space cans that was the practice of early space travel in 1960s, space agencies are now more aware and concerned about safety of humans that spend months in orbit on the International Space Station.