GEOMAGNETIC STORM PREDICTED (G2): NOAA analysts say that a G2-class (Moderate) geomagnetic storm is possible on July 3rd when yesterday's X-class CME reaches Earth. In the northern hemisphere, aurora visibility will be challenged by several factors: (1) a bright moon, (2) short nights, (3) the Russell-McPherron Effect, which suspresses solstice auroras. The best time to look is during the dark hours around midnight. Aurora alerts: SMS Text.
EARTH-DIRECTED X-FLARE AND CME (UPDATED): As predicted, sunspot 4479 erupted on June 30th, producing an X1.1-class solar flare. NASA's Solar Dynamics Observatory (SDO) recorded the extreme ultraviolet flash: movie.
Above: SDO image of the X-flare with a photo of sunspot 4479 inset. Credit: Sylvain Weiller
During the flare, radiation ionized Earth's upper atmosphere, creating a shortwave radio blackout over North America and the Pacific Ocean: map. Mariners and ham radio operators may have noticed loss of signal at frequencies below 25 MHz around 20:50 UTC.
Of greater interest is the CME. Coronagraph images show a full halo CME heading almost-directly toward Earth. NASA and NOAA models differ slightly on its time of arrival. NASA favors late on July 2nd, NOAA favors early on July 2nd. Either way, a geomagnetic storm is possible before the end of the week, probably category G2. Solar flare alerts: SMS Text.
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A COMET JUST PLUNGED INTO THE SUN: Hours before yesterday's X-flare, a comet plunged into the sun and disintegrated. NOAA's CCOR-1 coronagraph on GOES-19 recorded the death dive:
The comet was likely a member of the Kreutz family. Named after a 19th century German astronomer who studied them in detail, Kreutz sungrazers are fragments from the breakup of a giant comet at least 2000 years ago. Several of these fragments are thought to pass by the sun every day. Most are too small to see but occasionally a bigger fragment like this one attracts attention.
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