DEEP SOLAR MINIMUM: Solar Minimum is underway, and it's a deep one--perhaps the deepest of the Space Age. So far this year the sun has been without sunspots 73% of the time, matching the record previously set in the year 2008. If the sun remains blank for the rest of this week, 2019 will edge past the Space Age record for sustained spotlessness. Keep an eye on the spotless days counter for updates.
THE TAIL OF INTERSTELLAR COMET BORISOV: When interstellar visitor 'Oumuamua flew through our solar system in 2017, researchers could not figure out what the cigar-shaped object was. Ideas ranged from an alien light sail to a fossilized comet. Now another interstellar visitor has arrived: 2I/Borisov. And it's definitely a comet. This Oct. 11th video recorded by amateur astronomer Michael Jäger of Weißenkirchen, Austria, clearly shows Borisov's tadpole-like tail:
Capturing an interstellar comet tail with a backyard telescope is an impressive accomplishment. "2I/Borisov is very faint--about 17th magnitude," notes Jäger. "The seemingly-bright stars in the animation are actually quite dim, ~8th to 9th magnitude. They don't even have proper names."
What's the tail made of? To answer that question, in September an international team of astronomers led by Alan Fitzsimmons took a closer look using the 4.2 m William Herschel Telescope on La Palma. They've just reported the results.
Above: The near-UV spectrum of 2I/Borisov obtained at the William Herschel Telescope. [more]
Borisov's tail is rich in CN, a.k.a. cyanide. The comet's nucleus is pumping out approximately 4x1024 CN molecules every second. That may sound extraordinary, but it is not. Here in the Solar System, cyanide is commonly found in comet tails, and the production rate in Borisov is similar to that of local comets. Combining the production rate of CN with other factors, such as the comet's brightness and apparent dustiness, the researchers calculate that 2I/Borisov's core is between 0.7 km to 3.3 km wide--again, typical of ordinary comets.
"Overall," the authors note, "we find the gas, dust and nuclear properties for this first active Interstellar Object are similar to normal Solar System comets." In other words, wherever Comet Borisov came from, it must be a lot like here.
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MEMORIAL SPACE PENDANT: Consider it a space capsule for a loved one. On Oct. 6, 2019, the students of Earth to Sky Calculus launched this unique memorial urn pendant to the stratosphere onboard one of their cosmic ray balloons. The sparkling blue heart flew 108,893 feet above Earth's surface:
You can have it for $129.95. The students are selling memorial urn pendants to support their cosmic ray ballooning program. Buy one and we'll fly it again for free with ashes you provide inside the pendant's screw-topped chamber. It's an affordable way to send remains to the edge of space. The pendant and its contents will be returned to you at the end of the flight.
Each pendant comes with a greeting card showing the item in flight and telling the story of its journey to the edge of space and back again.
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