A "CANYON OF FIRE" ON THE SUN: During the late hours of July 8th, a magnetic filament on the sun became unstable and snapped. The eruption cut a "canyon of fire" in the sun's atmosphere and hurled a faint coronal mass ejection (CME) into space. NOAA analysts are modeling the CME now to see if it might hit Earth's magnetic field in the days ahead. Stay tuned for updates. Aurora alerts: SMS Text.
COMET NEOWISE HAS A SUPER-SIZED NUCLEUS: Now we know why Comet NEOWISE (C/2020 F3) is so bright. Its nucleus is huge. Researchers working with NASA's NEOWISE spacecraft have analyzed infrared emissions from the comet's core, shown here in discovery images from March 2020:
The glow is proportional to the size of the nucleus--the nugget of dust and frozen gas at the heart of the comet. "From its infrared signature, we can tell that [the nucleus] is about 5 kilometers across," says Joseph Masiero, NEOWISE deputy principal investigator at NASA's Jet Propulsion Laboratory.
"5 km is extremely large for a comet approaching this close to the sun (think Comet McNaught-sized), which explains its high activity," says Qicheng Zhang, a PhD student in planetary sciences at Caltech.
On July 3rd, Comet NEOWISE passed by the sun near the orbit of Mercury. The oversized nucleus helped it survive the encounter, which some comets would have found too hot to handle. Now NEOWISE's sun-heated core is spewing massive amounts of dust and gas, creating a worldwide sensation.
"Here is my daughter Izar ('Star' in the Basque language) pointing out the comet in the sunrise sky over Girona, Catalonia, Spain," says photographer Juan Carlos Casado. "It was easy to see with the naked eye."
"Foreground lighting in the photo is natural, provided by the Moon," he adds.
For Comet NEOWISE, the future looks bright. Its large nucleus is a reservoir of dust and gas that should continue to fill the comet's double tail with visible material for weeks to come. Observing tips: Wake up about 90 minutes before sunrise, find a place with a clear horizon, and look northeast. The comet is visible to the naked eye as a fuzzy patch with a tail. Binoculars are recommended for full effect. Sky maps: July 9, 10, 11, 12, 13, 14, 15.
Realtime Comet NEOWISE Photo Gallery
Free: Spaceweather.com Newsletter
THE MESOSPHERE IS STILL COLD: Noctilucent clouds (NLCs) have been extra-abundant this summer. Nearly half of all photos of Comet NEOWISE taken from Europe in the past few mornings have caught the comet surfing waves of electric blue. The reason: It's cold in the mesosphere. Very cold. These data from NASA's Microwave Limb Sounder (MLS) show how the temperature has cratered 83 km above Earth where NLCs form:
Lynn Harvey of the University of Colorado's Laboratory for Atmospheric and Space Physics made the plot, which spans 14 years. 2020 is traced in red. "Conditions continue to be extremely cold with temperatures setting cold records on some days," she says.
For noctilucent clouds, cold is good. NLCs form when summertime wisps of water vapor rise up to the mesosphere, allowing water to crystallize around specks of meteor smoke. Low temperatures help the ice crystals form.
In addition to a major outbreak in Europe, the clouds have spread across the USA to southern California. This means everyone should be watching for them. The best time to look for NLCs is during the hours after sunset (or before sunrise) when the sun is more than 6 degrees below the horizon: diagram. If you see electric-blue tendrils spreading across the sky, take a picture and submit it here.
Realtime Noctilucent Cloud Photo Gallery
Free: Spaceweather.com Newsletter
NEED BABY YODA, YOU DO: Baby Yoda has been to the stratosphere. The future Jedi left Earth on May 21st aboard an Earth to Sky Calculus cosmic ray balloon. Here he is floating Force-free 107,611 feet above Earth's surface:
You can have Baby Yoda for $119.95. The students are selling these adorable bobbleheads to support their cosmic ray ballooning program. They make great birthday, Christmas, and graduation gifts. Each one comes with a greeting card showing Yoda in flight and telling the story of its journey to the edge of space and back again.
Far Out Gifts: Earth to Sky Store
All sales support hands-on STEM education
Realtime Space Weather Photo Gallery
Free: Spaceweather.com Newsletter