Nov. 25, 2022: The British Astronomical Association (BAA) is reporting a new outburst of cryovolcanic comet 29P/Schwassmann-Wachmann. On Nov. 22nd, the comet’s nucleus suddenly brightened by more than 4 magnitudes–a sign that a major eruption was underway. Cryomagmatic debris is now expanding in a shell shaped like Pac-Man:

Cai Stoddard-Jones took the picture on Nov. 23rd using the Faulkes Telescope North in Hawaii. At the time, the shell was already more than 100,000 km in diameter.

The Pac-Man shape of the ejecta shows that this is not a uniform global eruption. Instead, it is coming from one or more discrete sources on the comet’s surface.

This fits a leading model of the comet developed by Dr. Richard Miles of the British Astronomical Association. Miles believes that 29P is festooned with ice volcanoes. There is no lava. The “magma” is a cold mixture of liquid hydrocarbons (e.g., CH4, C2H4, C2H6 and C3H8) akin to those found in lakes and streams on Saturn’s moon Titan. The comet’s cryomagma is suffused with dissolved gases N2 and CO, a bit like carbonation in a soda bottle. These bottled-up volatiles love to explode when a fissure is opened by the warming action of sunlight.

A new image taken on Nov. 25th by astronomers André Debackère and M. Malaric adds weight to the idea that a single volcano is driving the outburst. Processing the data with a rotational gradient filter, Debackère found a bright plume of debris at position angle 330 degrees (the 1 o’clock position):

This narrow plume probably leads back to the primary source the eruption. Currently streaming away from the nucleus at 75 m/s (270 km/hr), the plume stretches more than 11,000 km into space. If an eruption like this were happening on Earth, it would be plastering thousands of satellites with frosty hydrocarbons.

The integrated brightness of the comet (magnitude +11), puts it within easy reach of many backyard telescopes. Pac-Man already subtends an angle wider than Mars and, if past eruptions are any guide, it should grow much larger in the nights ahead. Observers can find 29P after sunset in the constellation Gemini.

For more information visit the British Astronomical Association’s MISSION 29P website.

more images: from Tom Gwilym of Sturgeon Bay, Wisconsin;

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Nov. 13, 2022: Evidence is mounting that AST SpaceMobile’s BlueWalker 3 satellite has unfurled its its huge antenna. Multiple observers have seen the satellite shining like a 1st magnitude star–a 50-fold increase in brightness compared to just a few days ago. Paul Maley of Arizona saw it in bright morning twilight on Nov. 11th, and Gary Dowdle of Texas caught it just before sunrise on Nov. 12th:

“The satellite was very low in the northeastern sky, about 16.5 degrees above the horizon,” says Dowdle. “Nevertheless, it was easily visible to the naked eye at magnitude +2 just below the handle of the Big Dipper.”

Paul Maley saw it again on Sunday morning, Nov. 13th. “It came out of Earth’s shadow at magnitude +3 then steadily brightened to magnitude +1,” he says. “Its visual profile remains unchanged over the last 3 days. The spacecraft appears completely stable with no signs of tumbling.”

BlueWalker 3 is a revolutionary communications satellite designed to provide cell phone service from space. To detect weak cell phone signals from Earth’s surface it needs a very large antenna. BlueWalker 3’s is about the size of a squash court:

Astronomers have worried that BlueWalker 3 could become one of the brightest objects in the night sky, reflecting bright beams of sunlight into telescopes on the ground below. Those fears have not been fully realized. If the satellite is really only as bright as a 1st magnitude star, then it would be no worse than, say, China’s Tiangong space station or the ISS.

It may be too soon to relax, though. While this is only a single satellite for now, Bluewalker’s maker AST SpaceMobile plans to launch more than 100 larger satellites called BlueBirds. These satellites could be more than twice the size of BlueWalker 3 and much brighter. Flocks of Bluebirds could ruin a lot of astronomical observations.

Set against this detriment to astronomy is the good these satellites could do by providing emergency services and cell phone connectivity to remote areas. AST SpaceMobile explains.

You can help monitor BlueWalker 3. Morning and evening flybys are currently happening over the USA. Check Heavens Above for local flyby times and let us know what you see.

UPDATE: The CEO of AST SpaceMobile confirmed in a Tweet this morning that BlueWalker 3 has indeed unfurled its antenna, accounting for the observations described below. He also shared images of the antenna taken from orbit with different sun angles.

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Nov. 6, 2022: It could happen again–and soon. Twenty-one years ago, a full-halo CME struck Earth’s magnetic field, sparking a severe G4-class geomagnetic storm. “Skies over Central Europe glowed bright red and violet,” recalls Heiko Ulbricht, who photographed the display from Saxony, Germany, on Nov. 6, 2001:

“The shock front hit the Earth’s magnetic field around 2 a.m. CET–good timing for sky watchers in Europe,” says Ulbricht. From there, auroras spread around the world, descending as far south as Florida, Texas, and California in the United States. The storm persisted for more than 24 hours.

The CME left the sun two days earlier, propelled by an X1-class solar flare from sunspot AR9684. SOHO coronagraph images of the CME were quickly overwhelmed by a “snowstorm” of energetic particles accelerated by shock waves in the approaching storm cloud:

The kind of explosion that produced this storm is, interestingly, not rare. Young Solar Cycle 25 has already produced 8 similar X-flares since 2021. None of the related CMEs delivered a direct hit, however.

“If you look at the sun today, it could definitely produce a spectacle of this kind again,” says Ulbricht. Browse the aurora gallery from 21 years ago to see what might be coming.

Nov. 6, 2001, Aurora Photo Gallery
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Oct. 31, 2022: Have you ever heard of the “Halloween Fireballs?” Astronomers call them Taurid meteors. They appear every year from late October through early November when Earth passes through a stream of debris associated with Comet 2P/Encke. Dan Bush photographed this Taurid exploding over Albany, Missouri:

“Fireball season has arrived,” says Bush. “I have caught many with my meteor camera system including this Taurid fireball above the clouds on Oct. 27th and another good one on Oct. 28th”

We’re about to see a lot more of these. Forecasters believe that a swarm of Taurid meteoroids is approaching Earth, and it could double the usual rate of fireballs–not only on Halloween, but also through the early weeks of November.

Taurid meteors are thought to be debris from a giant comet that broke apart in the inner Solar System 10 to 20 thousand years ago. The breakup produced a mixture of dust and larger bodies that are still present today. Comet 2P/Encke itself may be just one of the fragments.

Over the years, Jupiter’s gravity has shepherded some of these meteoroids into a well-defined cloud–the “Taurid Swarm.” It visits Earth every 3 or 7 years. Previous encounters with the Swarm in 2005 and 2015 produced showers of fireballs observed around the world. The last outburst was 7 years ago, which means 2022 should be a Swarm year, too.

In 1975 the Swarm contacted the Moon, making Apollo seismic sensors ring with evidence of objects hitting the lunar surface. If there’s a repeat strike this year, Nov. 8th might be a good time to look for it. The Moon’s surface will be darkened by Earth’s shadow during a total lunar eclipse, improving the visibility of any exploding lunar meteors.

Although the Taurid shower typically peaks on Nov. 5th, it is a broad maximum, weeks long. Any of the nights ahead could produce a Taurid display. Look up during the hours around midnight; you can expect to see a few fireballs per hour streaking from the horns of Taurus–and many more if the Swarm arrives.

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