The Solar Wind Has Arrived
Photo credit: Doug Zubenel of DeSoto, Kansas. August 3, 2019.
As predicted, today Earth is entering a stream of solar wind flowing from a large hole in the sun’s atmosphere. NOAA forecasters say there is a 55{154653b9ea5f83bbbf00f55de12e21cba2da5b4b158a426ee0e27ae0c1b44117} chance of G1-class geomagnetic storms on Aug. 5th and 6th.
High-latitude sky watchers should be alert for auroras, especially in the southern hemisphere where winter darkness favors visibility. Aurora alerts: SMS Text
RAIKOKE SUNSETS
This weekend in DeSoto, Kansas, something strange happened to the sunset: It turned purple. “On Saturday night, I photographed a large dome of pinkish-purple light,” reports Doug Zubenel. “Strong crepuscular rays were also visible.”
Purple sunsets are a sign of volcanic activity. Fine volcanic aerosols in the stratosphere scatter blue light which, when mixed with ordinary sunset red, produces a violet hue.
But which volcano? The answer is probably Raikoke, a volcano in the Kuril islands which erupted with such force on June 22, 2019, that it was seen from the International Space Station. NASA satellites confirm that aerosols from Raikoke reached the stratosphere and they have been circulating around the Northern Hemisphere ever since.
A similar eruption occurred 11 years ago, in Aug. 2008, when Alaska’s Kasatochivolcano spewed sulfurous gases into the stratosphere. For months sky watchers witnessed strange sunsets whenever a plume of Kasatochi’s emissions drifted overhead. The same thing, apparently, is happening now thanks to Raikoke.
Photo credit: Heiko Ulbricht in the Zittau Mountains of southeastern Germany. July 26, 2019.
Volcanic sunsets have also been seen in Halifax, Nova Scotia; in the Zittau Mountains of Germany; in Joshua Tree, California; in Orange, California.
Purple isn’t the only thing to look for, says atmospheric optics expert Les Cowley. In addition, he advises, sky watchers should “be alert for a very bright yellow twilight arch, fine cloud structure in the arch seen through binoculars, and long diffuse rays and shadows.”
THE EERIE CALMING OF EARTH’S MAGNETIC FIELD
Solar Minimum is having a calming effect on Earth’s magnetic field. The deepening quiet is shown in these geomagnetic data, taken by Stuart Green of Preston, Lancashire, UK, during each of the past 3 summers:
Watch video:
https://youtu.be/zT63_T9nY8Q
“I’ve plotted the changing levels of geomagnetic activity for the months of May, June and July (between the equinoxes) for the years 2017, 2018 and 2019,” explains Green, who operates a research-grade magnetometer buried in his backyard. “The trend is clearly downward, with less frequent and intense storms in 2019, as the sun continues deeper into Solar Minimum.”
His data show why minor G1-class geomagnetic storms, which would rarely be mentioned during Solar Maximum, are suddenly noteworthy. Any magnetic storm is news at this point in the solar cycle.
The quiet won’t last forever, though. A panel led by experts from NOAA and NASA predict that the solar cycle will bottom out in late 2019 with a bounce back to higher levels of activity beginning sometime in 2020. Meanwhile, G1 is a significant magnetic storm. Stay tuned.
Read more at www.spaceweather.com
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