Radiation from the X1.9 blast caused a shortwave radio blackout over the Pacific Ocean, leading to a loss of signal at frequencies below 25 Megahertz (MHz). Amateur radio operators, especially in Hawaii, may have noticed the signal loss.<\/p>\n
Solar flares are intense bursts of radiation from the sun. The most powerful explosions in the solar system, they can can contain as much energy as a billion hydrogen bombs, according to NASA.<\/p>\n
Solar flares are classified according to their intensity, with X being the highest on the scale. X-class solar flares can cause planet-wide radio blackouts and long-lasting radiation storms.<\/p>\n
![\"Solar](\"https:\/\/www.europesays.com\/us\/wp-content\/uploads\/2025\/06\/solar-flare-causes-blackout-us.jpg\")
\nA map showing the areas affected by the solar flare, including large parts of the United States. Inset, an image of the solar flare.
\nA map showing the areas affected by the solar flare, including large parts of the United States. Inset, an image of the solar flare.
\nNOAA\/SWPC\/NASA<\/p>\n
The latest solar flare follows an M-class one, the second-highest on the scale, that occurred days earlier on June 15<\/a>. It caused a shortwave radio blackout across North America, with a loss of signal seen at frequencies below 20 Megahertz (MHz).<\/p>\n Unlike the M8.3 solar flare on Sunday, the solar flare on Thursday did not launch a Coronal Mass Ejection (CME)\u2014a massive burst of plasma and magnetic field lines\u2014into space.<\/p>\n However, the explosion has apparently destabilized a magnetic filament in the sun’s southern hemisphere.<\/p>\n This massive filament, which is erupting now, may produce a CME, which could lead to geomagnetic storms.<\/p>\n “When a CME arrives at Earth, it can produce some of the biggest geomagnetic storms and thus, some of the brightest and most active auroras that extend furthest toward the equator,” explained NOAA. Geomagnetic storms caused by CMEs can lead to aurora borealis, also known as the northern lights.<\/p>\n The northern lights are formed from electrons colliding with the upper reaches of Earth’s atmosphere.<\/p>\n During these collisions, “the electrons transfer their energy to the atmosphere thus exciting the atoms and molecules to higher energy states” and “when they relax back down to lower energy states, they release their energy in the form of light,” explains the Space Weather Prediction Center.<\/p>\n Stronger solar cycles produce more solar storms with greater intensity, which drives geomagnetic activity.<\/p>\n “If the geomagnetic field is active, then the aurora will be brighter and further from the poles,” where the northern lights are typically most visible, says the Space Weather Prediction Center. This means that the aurora borealis may be viewed from lower latitudes than usual.<\/p>\n Last year, strong solar activity allowed northern lights enthusiasts<\/a> to catch a rare viewing of the natural display<\/a> in parts of the world where they’re normally not seen, such as in Japan.<\/p>\n![\"A](\"https:\/\/www.europesays.com\/us\/wp-content\/uploads\/2025\/06\/solar-flare-erupting-june-19.jpg\")
\nA solar flare erupting on June 19, causing the radio blackout.
\nA solar flare erupting on June 19, causing the radio blackout.
\nNASA \/ Solar Dynamics Observatory<\/p>\n