Some unusual astronomical events in 2019

A couple of thought-provoking astronomical events – or perhaps more accurately, observations this year. Most recently, Tomboktu pointed me towards this story about Betelgeuse, the star, which is 600 light years away and is dimming. As National Geographic notes;

Normally, Betelgeuse is among the 10 brightest stars in the sky. However, the red giant began dimming in October, and by mid-December, the star had faded so much it wasn’t even in the top 20, Villanova University’s Edward Guinan reported in an Astronomer’s Telegram.

And this may be a precursor…

To be clear, dimming alone isn’t all that odd for a star like Betelgeuse. It’s what’s known as a variable star, and its shifts in brightness have been closely studied for decades. However, it is unusual for one of the sky’s most prominent points of light to fade so noticeably, prompting scientists to consider the possibility that something more exciting could be about to happen: Betelgeuse might explode and die, briefly blazing brighter than the full moon before vanishing from our night sky forever.

By the way, this is visible, with the constellation of Orion now ‘noticeably different’ due to the dimness of the star which is part it.

Interestingly this year came to the conclusion that the interstellar object Oumuamua which passed through the solar system two years back was of ‘purely natural origin’. Some had theorised that it might even be an artificial object.

Another object that was the cause of much interest a few years back, Tabby’s Star, or KIC 8462852, when it exhibited unusual light fluctuations, saw some reasonably definitive conclusions as to its likely provenance. As wiki notes:

In September 2019, astronomers reported that the observed dimmings of Tabby’s Star may have been produced by fragments resulting from the disruption of an orphaned exomoon.[22][23][24] An overall study of other similar stars has been presented.[25][26]

Another visitor to the Solar System is Comet2I/Borisov, the first identified comet from another star.

Crimean amateur astronomer Gennady Borisov discovered the comet on Aug. 30, 2019, and reported the position measurements to the International Astronomical Union’s Minor Planet Center in Cambridge, Massachusetts. The Center for Near-Earth Object Studies at NASA’s Jet Propulsion Laboratory in Pasadena, California, working with the Minor Planet Center, computed an orbit for the comet, which shows that it came from elsewhere in our Milky Way galaxy, point of origin unknown.

Nevertheless, observations by numerous telescopes show that the comet’s chemical composition is similar to the comets found inside our solar system, providing evidence that comets also form around other stars. By the middle of 2020 the comet will have already zoomed past Jupiter’s distance of 500 million miles on its way back into the frozen abyss of interstellar space.

Then there’s this fascinating opinion column in Scientific American which suggests that we may have found life in the 1970s when Viking landed on Mars…

And from the same magazine one of the neatest solutions to the Fermi paradox, that being the question as to why if alien life is likely in the universe (quite an assumption in itself) we haven’t found any yet – it’s not online, but it’s entitled The Galactic Archipelago and it is written by Caleb Scharf, and this piece on wiki offers at least a part of the possible answer (as well as being intriguing in itself).

But as always with astronomy there are the big issues. The really big issues. As the Guardian noted last month:

Astronomers have reached a fundamental impasse in their understanding of the universe: they cannot agree how fast it is flying apart. And unless a reasonable explanation can be found for their differing estimates, they may be forced to completely rethink their ideas about time and space. Only new physics can now account for the cosmic conundrum they have uncovered, many believe.