THE SOUTHWORTH PLANETARIUM
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43.6667° N    70.2667° W  Altitude:  10 feet below sea level Founded
January 1970
2021-2022: XVI "When G-d sneezed, I didn't know what to say."
-Henny Youngman

THE DAILY ASTRONOMER
Thursday, September 23, 2021
Something Hit Jupiter

on September 13, 2021.    The many astronomers who observed this spectacle
aren't quite sure what struck this king of the gas giants.  Hence, the
vaguely-worded announcement,  "Something hit Jupiter."      That the impact
was even recorded in the first place was a sweet serendipity.   Many
astronomers,* including Brazilian astronomer* Jose Luis Pereira, were
recording a Ionian transit, the passage of Jupiter's moon Io directly in
front of the planet.  During the recording, Pereira noticed a bright,
two-second long flash.      Astronomers in Germany also recorded the event
and concluded that the outburst occurred on the giant planet as opposed to
having happened merely along its sight line.

[image: impact2021-09-13_22-43-09_irgb_HPa.jpg]

The videos were analyzed by astronomers and astrophysicists around the
world, including Marc Delcroix at the NTT Communication Science
Laboratories in Kyoto, Japan.     Based on the initial studies conducted
within the brief time immediately following the impact, astronomers
estimate that the impacting body was approximately 20 meters in diameter.
    They speculate that this object might have been a fragment of a comet
or asteroid that ventured too close to Jupiter and was split into pieces by
the planet's gravity.

This latest impact event reminds us of the most famous astronomical
cometary collision in modern history:   the impact of Comet Shoemaker-Levy
9 onto Jupiter in 1994.

[image: illustration-of-shoemaker-levy-9-and-jupiter.jpg]

During that spectacular event, Jupiter's tidal forces tore the comet into
pieces, all of which rained down onto the Jovian cloud tops with the power
of thousands of tons of TNT.     In the above image, we can see the doomed
cometary particles prepared to meet their fate.    The destruction of
Shoemaker Levy 9 was observed and followed by thousands of astronomers
around the world.   This latest impact was seen only by a few astronomers,
none of whom expected to see it.

Over the next few weeks. astronomers will closely examine the impact's
light curve: the way the light intensity varied over the brief interval
during which it remained visible.   Such light curve analysis should yield
information about the impact speed, as well as the composition, size and
other characteristics of the impacting body.

Although the solar system has become much more quiescent since the
ultra-violent heavy bombardment days , millions of asteroids, comets and
other projectiles continue to tumble through inter-planetary space.
 They will occasionally strike larger bodies, including our home world.
 That is perhaps why we love to observe collisions on other planets.  Such
impacts events are all spectacle and no catastrophe.  Then again, they also
serve as  reminders that menaces still lurk deep within the  hollows of
that perpetual night.



*Unlike most media sources, the DA will never use the term "amateur
astronomer." We  won't include that term in these articles for the same
reason that we'll never include the words (censored), (censored) or
(censored).   "Amateur astronomer" is an appalling insult. [If you doubt
this assertion, try the following experiment: Next time a plumber or
electrician visits your home, present him/her with a plate of cookies and
say, "These are for my favorite amateur."  See what sort of reaction you
elicit.]     The proper term is "astronomer."    PhD level research
astronomers are all astrophysicists.  Astronomers, such as those affiliated
with the Southern Maine Astronomers [ www.southernmaineastronomers.org ]
 have performed sterling work in both research and educational outreach.
 Most of their members have forgotten more about astronomy than I'll ever
know.  They are no amateurs.


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