GEOMAGNETIC UNREST IS HAPPENING: Earth's polar magnetic field is quivering on July 24th as our planet enters an unsettled stream of solar wind. The stream *might* contain the remains of a slow-moving CME that left the sun on July 19th--or the CME might arrive later. Either way, high-latitude sky watchers should be alert for auroras and STEVE. Aurora alerts: SMS Text.
SOLAR CYCLE 25 SUNSPOT: Sunspot AR2767 is turning to face Earth. Earlier today, Martin Wise of Trenton, Florida, photographed the active region in high resolution:
"I captured AR2767 with a resolution of 0.2 arcseconds per pixel," says Wise. His image shows the sunspot's primary dark core (itself about the size of Earth), surrounded by a sea of boiling granules.
Sunspot AR2797 is a member of new Solar Cycle 25. We know because its magnetic polarity is reversed compared to sunspots from old Solar Cycle 24. See Hale's Law for more information. So far AR2767 is quiet and seems to pose little threat for strong flares. Solar flare alerts: SMS Text.
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CLOSE ENCOUNTER WITH COMET NEOWISE: Yesterday, July 23rd, Comet NEOWISE (C/2020 F3) made its closest approach to Earth--only 0.63 AU (103 million km) away. Harlan Thomas of Alberta, Canada, photographed the encounter through a sea of green airglow:
"I drove 240 miles from my home in Calgary to find clear skies for this special night," says Thomas. "The comet was visible to the naked eye, barely, so I started taking pictures. That's when the airglow appeared. It was so thick, it started to overwhelm the comet!"
Airglow looks like the aurora borealis, but it is not. The luminous haze is created by a complex assortment of chemical reactions in the upper atmosphere. These reactions get started during daylight hours when the atmosphere is bathed in strong UV radiation from the sun. At night we see the afterglow, colored green by oxygen atoms 90-100 km high and red by hydroxyl ions 86-87 km high. Thomas's photo captured both.
After today, Comet NEOWISE will recede from Earth, starting its long journey back to the outer reaches of the Solar System. The comet won't vanish right away. It'll remain a borderline naked-eye object for another week or so and an easy target for digital cameras well into August. Sky maps: July 22, 23, 24.
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A GIFT FOR STAR WARS FANS: A good bounty hunter will go just about anywhere. On Jun 13, 2020, the Mandalorian hitched a ride to the stratosphere onboard an Earth to Sky Calculus cosmic ray balloon. Here he is, floating 113,189 feet above the Sierra Nevada mountains of central California:
You can have him for $114.95. The students of Earth to Sky are selling Mandalorian bobbleheads to raise money for their cosmic ray ballooning program. Each figurine comes with a greeting card showing the bounty hunter in flight and telling the story of his journey to the edge of space and back again. They make great gifts for Star Wars fans.
Far Out Gifts: Earth to Sky Store
All sales support hands-on STEM education
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