SOLAR WIND, INCOMING: A stream of solar wind could graze Earth's magnetic field on May 10th, causing geomagnetic unrest at high latitudes. The gaseous material is flowing from a far-southern hole in the sun's atmosphere. It might miss--but if not, sub-Arctic and Antarctic sky watchers could see a display of auroras this Sunday. Aurora alerts: SMS Text.
WHAT JUST HAPPENED TO COMET SWAN? This week, an unexpected outburst from Comet SWAN (C/2020 F8) amazed observers in the southern hemisphere, who could actually see the comet brighten with their unaided eyes.
What happened? It might have fragmented, exposing bright clouds of dusty gas to the sun. Certainly the comet's tail looks like debris from an explosion:
Above: Comet SWAN photographed by Gerald Rhemann of Farm Tivoli, Namibia on May 1st. [more]
But Karl Battams of the Naval Research Lab in Washington, DC, doesn’t think so. "Outbursts do not necessarily imply fragmentation, and ground-based images are not yet showing evidence of a breakup," he says. "This could just be a particularly feisty and volatile comet."
Comet SWAN was discovered on April 11th when Australian amateur astronomer Michael Mattiazzo noticed a curious "bloom" in images from SOHO's SWAN camera. SWAN surveys the solar system for hydrogen gas, and it caught the comet making a sudden hydrogen dump. That might have been Comet SWAN’s first outburst.
A second outburst starting in late April turned SWAN into a naked eye object:
Fresh comets often behave this way–cracking, fracturing, and exposing veins of volatile material as they approach the sun for the first time. Comet SWAN is just such an object. It has a hyperbolic orbit, which suggests it has never been here before. Sunlight is touching its surface for the first time with unpredictable results.
More outbursts could be in the offing. Dates of special interest include May 12th when the comet passes by Earth (0.56 AU) and May 27th when the comet slingshots past the sun not far from the orbit of Mercury (0.43 AU). Observers in the southern hemisphere will have a front row seat for whatever happens.
"It would not surprise me at all to see another outburst – maybe several – in the coming weeks as it closes in on the sun later this month," says Battams.
Stay tuned!
A sharable version of this story with observing tips is available here.
Realtime Comet SWAN Photo Gallery
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CRYSTAL MOON BALL IN THE STRATOSPHERE: On Star Wars Day ("May the 4th be with you"), the students of Earth to Sky Calculus launched an array of cosmic ray sensors to the stratosphere. They do this every week or so to monitor increasing levels of atmospheric radiation. This crystal Moon ball went along for the ride:
You can have it for $129.95. The students are selling these far-out balls to support their cosmic ray ballooning program.
Each one comes with an LED base that turns the laser-etched crystaline Moon a beautiful shade of purple, blue, green or yellow. It makes a great night light. Also included is a greeting card showing the crystal ball 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 Aurora Photo Gallery
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Realtime Space Weather Photo Gallery
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