WILL ARCTIC SKIES TURN GREEN FOR CHRISTMAS? A minor stream of solar wind is approaching Earth. Estimated time of arrival: Dec. 24-25. No geomagnetic storms are expected, but the gaseous material could spark auroras around the Arctic Circle. Aurora Alerts: SMS Text.
THE FAINTING OF BETELGEUSE: One day, perhaps in our lifetimes, perhaps 100,000 years from now, the red giant Betelgeuse will dim a little--and then explode. The supernova will rival the full Moon in the night skies of Earth and cast shadows after dark. This month, Betelgeuse has dimmed a little. So far it has not exploded. Alan Dyer photographed the star rising as usual with the rest of Orion on Dec. 21st:
"This is Orion rising over my home in Alberta, Canada, on a partly cloudy and foggy night," says Dyer. "Yellow-red Betelgeuse is shining at upper left, reportedly dimmer than usual."
Betelgeuse caused a sensation among professional astronomers earlier this month when Edward Guinan of Villanova University and colleagues reported a significant "fainting" of the star. "[Betelgeuse] has been declining in brightness since October 2019, now reaching a modern all-time low of V = +1.12 mag on 07 December 2019 UT," they wrote. "Currently this is the faintest the star has been during our 25+ years of continuous monitoring."
Astronomers have long known that Betelgeuse is on the precipice of an energy crisis. It's about to run out of fuel in its core. When that happens, the star will collapse and rebound explosively, producing the first known supernova in the Milky Way since 1604. Experts in stellar evolution believe Betelgeuse could die at any time during the next 100,000 years--a blink of an eye on time scales of astronomy.
The current dimming did not herald that final blast. Betelgeuse is also a slow variable star, and this seems to be no more than an episode of slightly deeper-than-usual dimming. Orion remains in tact ... for now.
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CHRISTMAS GIFTS FROM THE EDGE OF SPACE: So far in 2019, the students of Earth to Sky Calculus have launched 41 space weather balloons to the stratosphere, measuring cosmic rays over 2 continents and 6 different US states. You can help them pay their helium bill by purchasing a Christmas gift from the edge of space:
Every item in the Earth to Sky Store has flown to the stratosphere alongside an array of cosmic ray sensors. Carried aloft by giant helium balloons, these unique gifts travel above 99.7% of Earth's atmosphere, experiencing space-like blasts of cosmic rays, extreme cold, and a wild ride parachuting back to Earth after the balloon explodes. Even Amazon doesn't carry items this far out.
Don't forget to enter coupon code "XMASRAYS" at checkout for a 10% holiday discount.
Far Out Gifts: Earth to Sky Store
All sales support hands-on STEM education
ROCK COMET FIREBALL: So you thought the Geminid meteor shower was finished? Think again. On Dec. 21st, Frankie Lucena recorded an apparent Geminid fireball over Cabo Rojo, Puerto Rico:
"I traced this meteor back to the constellation Gemini near Castor, so I'm thinking it is quite possibly a late Geminid," says Lucena. "Also, the green afterglow is typical of bright Geminid meteors."
Geminids are bits of dust and gravel from 3200 Phaethon. The strange "rock comet" peppers Earth with debris every year in December. Of all the debris streams Earth passes through every year, 3200 Phaethon's is by far the most massive. Summed up, dust in the Geminid stream outweighs other streams by factors of 5 to 500.
No wonder, then, that Geminid stragglers are still hitting Earth's atmosphere more than a week after the shower's peak (Dec. 13-14). The debris zone of 3200 Phaethon is that big. In fact, it's so big that NASA's Parker Solar Probe has seen it without even trying. Stay tuned for more on that story in the days ahead.
Bonus: Also shown in Lucena's video is a tethered aerostat radar system. US Customs and Border Protection uses the moored helium balloon for low-level air and ground surveillance.
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