THE SOUTHWORTH PLANETARIUM
70 Falmouth Street      Portland, Maine 04103
(207) 780-4249      usm.maine.edu/planet
43.6667° N    70.2667° W
Founded January 1970
2022-2023: XXVII
Sunrise: 6:54 a.m.
Sunset: 5:59 p.m.
Civil twilight ends: 6:28 p.m.
Sun's host constellation: Virgo the Maiden
Moon phase: Last Quarter Moon
Moonrise: 11:18 p.m.
Moonset: 3:14 p.m.
Julian date: 2459870.21
"Memories are like mulligatawny soup in a cheap restaurant. It is best not
to stir them." -P.G. Wodehouse


THE DAILY ASTRONOMER Monday, October 17, 2022
Dart Invader

HAPPY 28TH BIRTHDAY, NICK!
To the real scientist in the family.
________________________________________________
THANK YOU!
Thank you for not only for your kind e-mails and good wishes, but also for
your indulgence.    You signed up for the DA to receive information
pertaining to astronomy, not my personal life, even though the latter is
infinitely more enthralling.  Posting the note about my wife's labor to the
DA list was the most efficient way of notifying all my close relations and
friends of the impending birth.     Mother and daughter are well.  Juliet
Elanor was born at 9:58 p.m. on Saturday, October 8th.
Thank you all yet again.
________________________________________________


Frightful scenario.  Earth's citizens awaken.  Sirens blare. News dire.
Asteroid impact impending.  Global annihilation imminent.  Stocks rise.
 Run on toilet paper.   Shadow grows.   Upturned eyes widen. Flaming
interloper plummets.  Humans scurry frantically and pointlessly.  Brace
yourself!  Bang! Boom! Bam!   Primary impact!  Landform vaporized.   Debris
cast skyward. Secondary impacts numerous. Globe catches fire. Tertiary
impacts innumerable.  Continents tremble.    Sun blocked.  Photosynthesis
halts.  Decade-long winter begins.   Earth life decimated.    Planet
recovers.  Sun returns.   Surviving species subsist and evolve.
 Skyscrapers excavated.    Hyper-intelligent meerkat archaeologists
perplexed.

Or, so the story goes.
You  know the one:  the tale of the lethal asteroid careening inexorably
toward Earth sounding doom and destruction for all but the heartiest.
This scenario, which last occurred about  66 million years ago, dropped the
sledgehammer on the dinosaurs and ushered in the rise of the mammals,
including us self-important primates.

Could it happen AGAIN?

Well, yes, in fact, it could happen again.  In fact, over the course of the
next hundreds of millions of years, the probability of such an impact
becomes increasingly higher.  The consequences of such an asteroid strike
could prove catastrophic for any life forms extant at the time.      The
prospect of such an assault begs the question:     Can we do anything to
avert the disaster?

Planetary scientists who track and study potentially hazardous asteroids
(PHA) once claimed that we could, in theory, divert such an asteroid.
Now, following the success of the DART mission, they're claiming that, in
practice, we likely will do so.

Let's review:
On September 26th,  the golf cart sized DART (Double Asteroid Redirection
Test) probe crashed into Dimorphos, a 170-meter wide asteroid locked in
orbit around its larger companion Didymos.    Many watched the asteroid
growing ever larger in DART's camera.    Eventually, just as the asteroid's
rubble-lined surface came into clear view, the transmission stopped. The
probe smashed into its target, to the exultation of mission scientists!
(One of the few spacecraft crashes that ever elicited such a celebration.)

After the probe hit its target, we all waited to see what would happen.
 Mission scientists hoped that the impact would alter the asteroid's
motion.  It certainly did.  Prior to the DART strike, Dimorphos required 11
hours, 55 minutes to complete one orbit around Didymos.   Now, its orbital
period has shortened to 11 hours, 23 minutes!    That 32 minute reduction,
greater than most estimates predicted, constitutes a resounding success.

Yes, NASA can divert asteroids merely by striking them.

Of course,  Dimorphos is much smaller than any asteroid capable of
inflicting great harm onto the planet.  The asteroid that ended the
Cretaceous  Period measured about six miles in diameter.      However, if
such a large asteroid could be struck by a probe early enough, the
resultant trajectory alteration could be significant enough to divert its
path away from Earth.      The Center for Near Earth Object Studies,
managed at the Jet Propulsion Laboratory, has compiled an extensive list of
PHAs and is tracking them.    AsCNEOS scientists can predict the
probabilities of future impacts far in advance, they should be able to
identify any that could potentially strike Earth.      If they were to
knock that asteroid early enough, its path could be shifted away from our
planet.

So far, we know of no large asteroids destined to pummel our world.
However, if any such body were discovered, we'd at least possess the means
by which to defend ourselves.    Whether or not that defense would prove
sufficient remains to be seen.


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_______________________________________
To Juliet:

Let me first say, "You're welcome," for one day you will learn that we
almost named you Juliet Ophelia and you will likely thank us for changing
our minds.  Juliet Ophelia.  Two poignantly tragic, yet achingly beautiful
names.     Initially the combination seemed sublime, like the complementary
tones of  resonant woodwinds and bird song.   Then, on further reflection,
we realized that, though lovely in isolation, they were just too much when
conjoined, more like the overapplication of perfume.    So just "Juliet"
remains.  We enbowered "Ophelia" in asphodel and let her dissolve into a
quiet moon-silvered pond.

Good morning, Juliet.
Welcome to Earth.
I write to you on the very first full day of your life outside the
sumptuously furnished and comfortably warm womb where you gradually took
form over the last nine months.    If you're sensible -and how could you
not be- you are somewhat chagrined at having been ushered out so early, far
sooner than you should have been.   Forgive us your premature expulsion,
for it is an evolutionary convention: necessitated by our forebears'
ill-advised decision to walk upright.  Had our ancestors not been so vain
as to abandon the primate posture, you could have remained far longer in
your protective hovel.     As it is,  you went "full term" and are now out
here with us.    Despite the shock, we hope you'll find solace and comfort
in the company of your adoring parents.    We're the two who will be
fawning pathetically over you, caressing your head, kissing your face and
intensifying your longing for a return to the womb.

The pretty one is your mother.     As it is said that the baby spirit
selects the parent,  I congratulate you on your sound judgement.   You have
chosen well, indeed, for your mother is not merely a good person, but is a
cause of goodness in others.  When she smiles at you, she'll be smiling at
the best part of who you are.    This is how she smiles at everyone.  In so
doing, she naturally draws out everyone's finest aspects and they all feel
a sense of gentle elevation in her presence.       Though you'll know
nothing of this now, the time of your first acquaintance, you'll come
slowly to learn the unsounded depth of your mother's character and the
infectious efferesence of her spirit.   She is like the world, itself.  The
more you get to know her, the more beautiful she will become to you.

I am reluctant to write much about your father because, as your father,
I've been a rather poor judge of him.   So, in order to explain him, let me
explain his parents.   A relationship therapist would have looked at his
parents as an aerodynamicist regards a bumblebee:  looking with deep
puzzlement and not a little consternation at the material existence of a
theoretical impossibility. A sweet-natured Southern woman so sensitive and
refined she believed that every uttered curse  caused an Earthquake wed to
a sputtering barrel-chested Boston-bred Irish bonfire.     By all rights,
they should have annihilated each other in a spasm of gamma-rays on first
contact.    In fact, they were married for more than half a century and
would have persisted in their union for centuries more had the reaper not
intervened.    Your father, however, inherited their  incongruities:  an
elf-friend trapped in a linebacker's body.   Thus you'll often directly
observe only his profound sense of existential discomfort.  You'll see him
most clearly in darkness, hence his  chosen profession.

Let me next say "I'm sorry," for the many times when we'll offer
unsolicited advice, which, of course, is the age-old parental
prerogative.   We understand already that it will likely be half heard and
unheeded.    We also know that unlike knowledge, which can be cheerfully
acquired and gently imparted, wisdom is almost always dearly bought.
We'd love to save you the pain and trouble by giving it to you instead of
letting you earn it.   It doesn't work that way. Your Earth odyssey has
begun and so you will learn best when your unaccompanied treks become the
most arduous.

I'd also explain Earth, if I even knew how to begin.    As it is an ancient
world endowed with powers beyond our fathoming, it can well afford to
sit quietly for a while as its most bold and audacious species -to which
you belong- offers it flames and blasphemies. Yet, its quiescence won't
last forever.   In time, dearest Juliet, may you live to know all its
beauties and none of its reckonings.     Do know, however,  that the two
warm, lovely souls who midwifed you into the world are more the rule on
Earth than the exception.   Of course, in a situation as felicitous as
childbirth, they were at liberty to exhibit their benevolence openly.   On
a predator-laden planet, most find it prudent to conceal their better
selves. (What a world it would become if  only your mother could smile at
it.)

Today is the first of your life's two bookends.   The other, presumably and
hopefully, won't arrive until well into the 22nd century.   By that time
your parents will have long since become incorporated into the ages, along
with a good many others that you knew and for whom you harbored an abiding
affection.    As you approach the second bookmark, you will be soberingly
aware of life's ephemerality  and the inevitability of loss.      To be
born into a Universe that will persist for trillions of years while each of
us is apportioned a wafer-thin segment seems all too cruel a jest: enough
to taste, but not savor.  All the same, may this melancholy reflection
instill in you an irrepressible vigor that will not permit  you to simply
sigh away your senescence.

But, for now, a helpless infant rests her head on a shoulder, a firm
structure in a realm frightfully bereft of securities.      We ask for your
trust, which we know is asking too much, as we encapsulate you in a
makeshift carapace, shielded from the assailing gusts and ceaseless tumults
of our unquiet Earth.    Tomorrow you'll awaken into the same
mystifying world and you'll look at me as if to say,  "Aren't you a bit old
for this, Dad?"
                   "Most certainly," I'll answer as I cradle your body  and
carry you to look out the window to see the anachronism of cars and coffee
shops embedded in the heart of a quintessential New England village.   "Not
much sense in me, I'm afraid."   Of course, as Professor Von Helsing once
said, and as you will come to learn yourself,  We're all G-d's madmen.