[The mythological excursions resume on Monday.]
THE SOUTHWORTH PLANETARIUM
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Altitude:  10 feet below sea level
Founded January 1970
Julian Date:  24592545.18
2020-2021:  LXXXVII


THE DAILY ASTRONOMER
Wednesday,  February 10, 2021
Exploratorium XX:  Only Human

Dispense with that "human, only human," balderdash, Friedrich.    The human
race is utterly fantastic.  The most intensely alive, gorgeously imperfect,
and wildishly energetic beings that ever adorned themselves in ill-fitting
clothes whilst pretending to be cheerful conformists.   I know it is
fashionable for us to be gloaming glum and mired in self-recrimination
while regarding ourselves as miserable amalgams of dents, dings and
deficiencies. However, for just a few minutes, we're going to try to peer
through the gray pallor and perceive ourselves as we are:    the product of
thirteen billion years of conspiring physical forces followed by arduous
evolution with, perhaps, outside help.  (We don't know either way, of
course, but we're not about to disparage those who consider this
intervention either a certainty or high probability.)

We start with a chilling paleontological premise:  that if Earth's ticking
clock were rewound back to the preface, we, well, wouldn't be "we" anymore.
  The complex interplay of evolving life forms with changing climates, not
to mention the ever so dynamic predator-prey models, might not have favored
our antecedents and, well, we would now be unrealized probabilities in some
ghost universe.  (And, by heavens, then we would have cause for glumness.)
____________________________________________
*Yes, we have noticed that nothing happens particularly quickly:  though
inexorable, the evolutionary process lumbers instead of sprints.*
________________________________________________

[image: Screen Shot 2015-03-20 at 11.19.56 PM.png]
Now, you could say we started when the Eukaryotic Domain took form about
2.1 billion years ago today.   The cells developed powerful little nuclei,
thereby differentiating themselves from the less ambitious prokaryotic
cells.   More than a billion years of splashing around in the seas were
needed before the first animals arrived about 590 million years ago.
These had no backbones, of course, and logically, by having no backbone,
they maintained an unchallenged political dominance until the phylum
Vertebrata showed up about 60 million years later.      Fast forward 310
million years later and the Mammalia class took root...well, not literally.
  At that time the mammals were still only laying eggs.   One hundred and
sixty million years ago, the subclass Theria developed the capacity for
live birth.  This "skill" came very handy, because those thug dinosaurs
were still milling about and, according to all the restaurant reviews still
extant in the geological record, they considered mammals eggs a covetous
delicacy.      We have to wait until about 100 million years ago for the
first primates to emerge from the underbrush.    The actual order primates
showed up about 25 million years later.    Around 63 million years ago, the
suborder Haplorrhini developed.  This suborder included the monkeys and
apes.   Fortunately, around the same time, the primates performed that
"destructive asteroid" summoning dance ritual, much to the amusement of the
T-Rexs and Triceratops.  Their laughter subsided when they heard the sonic
booms and looked up.

[image: human-evolution-promo-gettyimages-122223741.jpg]
Well, now, any Darwin reader will know where we go from here.   Through the
intervening millions of years, the apes and monkeys underwent  gradual
transformations.    The Hominid family formed around 15 million years ago.
   Two and a half million years ago the Genus Homo arrived.   To our modern
eyes, they would have looked somewhat human, albeit with pronounced simian
features.   The anatomically modern humans developed about 200,000 years
ago.      Provided the clothes were apt, hygiene thorough, and light level
low, they would have gone largely unnoticed in Times Square or Piccadilly
Circus.      Perhaps 70,000 years ago the truly modern human raised its
head from the mist and stepped proudly over the Discovery Channel logo at
the lower corner of the screen.     From these indefatigable
hunter-gatherers eventually arose the Africans, Sumerians, Babylonians,
Asians, Indigenous Australian, Indigenous American, Greco-Roman, and the
sundry other cultures I didn't include with the most profuse apologies.

Today, we are here: the latest generation in that powerful play of the homo
sapien sapien.


But you know, that is only part of the story.
That rapid fire and wholly inadequate synopsis of our history from cell to
cell phone misses the cosmic aspect of the tale.         We are forged out
of star fire.     When the Universe took form about 13.8 billion years ago,
a fiercely hot radiant energy filled the much smaller space then defined as
the Universe.   This radiant energy cooled sufficiently to allow the
simplest elements to form:   primarily hydrogen and helium.    The first
stars (Population III) congealed from this primordial matter and through
the thermonuclear fusion process transformed the lightest elements to
heavier elements.   Such fusion reactions power the Sun and the other
stars.       The highly massive Population III stars exploded as supernovae
and, in so doing, forged all the elements heavier than iron:, including
silver and gold.       These explosions not only created the heaviest
matter: they also dispersed it through space, chemically enriching the
medium.
[image: 2007-0528pulsar.jpg]
About five billion years ago, some of the debris cast off by a supernova
became incorporated into a gas dust cloud that collapsed to form a galactic
star cluster.  The Sun was one of the cluster members.  The peripheral
material around it coalesced into planets, moons, asteroids, comets, and
other bodies that now comprise the solar system.  One planet developed
conditions suitable for life.  Carbon, oxygen, phosphorus and the other
elements percolated and combined to make the first proteins, amino acids
and other building blocks from which life arose.     Had the only available
matter been hydrogen and helium, such constituents could never have risen
from the soup.  Stellar nucleosynthesis-the creation of heavier elements in
the stars- preceded the advent of life on this planet and any other life
bearing world....wherever they might be.

We became aware (sentient), grew curious, asked questions, pondered the
mysterious cosmos in which we found ourselves.  These contemplations gave
rise to profound natural philosophies that eventually became differentiated
into the sciences.  One of these, astronomy, started simply by the practice
of looking up.   How unaware the first astronomers were that by merely
looking up we would eventually be seeing within:  to the lattice work of
star dust comprising our bodies.

Could anything be more fantastic?


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