[image: The-Hunting-of-the-Great-Bear.jpg]
*Nyah-Gwaheh:   The Monster Bear*
More than a thousand years ago, in a village near a grand northern lake
within a vast continent called Turtle Island, there lived four hunters of
great renown.  They were known throughout the land for tracking and killing
any quarry they choose to pursue.   Moreover, these hunters were as
generous as they were successful so that no villager ever went hungry.
It is little wonder that they were widely celebrated and universally
adored.     On one winter day, when the world grew so cold that the lake
became as solid as the ground, a young boy ran into the village screaming
that he saw Nyah-Gwaheh, the monster bear, approaching.  "He is walking on
the lake and coming toward us!"     His desperate declaration inspired
little fear in the villagers for they all knew that Nyah-Gwaheh was merely
a legend.  Their elders and their elders' elders often wove fantastic tales
of the monster bear who was bigger than three bison and could touch the
tips of the tallest trees.  It was also said to be magical for it was as
old as the mountains and had been endowed with ancient magic.   Very few
people truly believed that it existed, for nobody had ever seen it and that
kind of bear would be difficult to miss.   Despite the boy's ardent pleas,
most of the villagers paid no heed to his warning.   However, one elder,
the oldest one in the village, took the boy's hand and whispered, "Show me
from where Nyah-Gwaheh comes."    Terrified, the boy didn't move, but only
pointed.    The elder slowly walked in the direction the boy indicated and,
though his eyes were quite aged, he soon saw an immense dark figure on the
lake.  It was moving quickly and inexorably toward him.  The elder hastened
back to the village and announced that a monster bear was indeed
approaching. Though the elders were known for their far-fetched tales, this
elder looked so serious that the villagers immediately believed him. Their
initial incredulity quickly turned into terror.   While everyone else ran
to their respective homes, the elder then walked to the home of the four
hunters which was located at the village's outer edge.  So much time
elapsed before he arrived that he worried that the bear might have already
come ashore.   The oldest hunter emerged to greet the elder, who then told
him about Nyah-Gwaheh.    The hunter quickly summoned the other three, all
of whom gathered their weapons. The hunters then ran quickly toward the
lake.  Well, three ran quickly.  One hunter, the youngest, had lately
engorged on their prey so much that he grew heavy and was slower than the
others.  (He alone brought a pouch of food with him before they all left.)
   When the hunters arrived in the village center, they found it deserted.
 They ran to the lake and to their surprise -and secret relief- saw no
bear.   However, they did detect traces of foot falls on the ice.      The
footprint was so enormous that they knew a monster bear had been there.
 "If the bear returns at night, it will devour all of our people," the
eldest hunter told the others. "We must follow the bear and slay it."   The
other hunters agreed to pursue the bear, though without much enthusiasm.

The hunters followed the bear tracks across the ice.   They were frightened
to see the substantial distance separating the successive footprints as it
was indicative of a great stride.   The hunters knew that this quarry was
far stronger and more fierce than any they had hitherto pursued.   After
many hours of walking, they followed the tracks onto a nearby shore and
into a thick forest.   "The tracks might be harder to follow here," the
youngest hunter lamented.   "Yes," the second youngest agreed, "but we go
on, anyway."     While they walked in the forest, all the hunters suddenly
experienced a deep fear, something that enveloped them like air.   "The
bear is here somewhere," the youngest hunter whispered. "I can feel him."
   "So do we," the eldest hunter replied tensely. "Be quiet."
The youngest hunter felt so nervous that he reached into his pouch to
nibble on food and found that it contained only worms.     "Look!" he said
to the other hunters, showing them the pouch.   "Nyah-Gwaheh is magical and
has turned my food into worms."  At the sight of the pouch, even the eldest
hunter's countenance darkened.     "We shall continue," he said with
determined calm.

They continued the pursuit even after the Sun was prepared to set.  They
had moved into the deepest part of the forest and lost sight of the track.
Not knowing what to do, and still sensing the bear, they decided to sit
together for a few minutes to rest and lit some torches. Yet, as soon as
the hunter lit the first torch,  they heard a fierce growl so thunderous it
shook the ground.   The second oldest hunter held the torch aloft and they
all saw two furry legs as thick and tall as tree trunks.   The bear growled
again, this time so loudly the hunters involuntarily screamed in response.
  They then clamored up and prepared their weapons: one had a bow and
arrows, the other an axe,  and two wielded clubs.       In spite of their
abject terror, they all exhibited great courage and rushed at the bear who,
curiously, fled from them.      Encouraged by Nyah-Gwaheh's retreat, they
quickened their pace as did the bear, himself.   Sooner than they expected,
the hunters emerged from the forest with the bear just beyond reach.  They
were all surrounded by stars which were so bright and numerous as to fully
illuminate the bear for the first time.      Nyah-Gwaheh's legend did not
do it justice. It was far more massive and larger than the hunters could
have ever imagined.  It towered over them almost like a mountain summit and
its hands were so vast only one of them could have wrapped around all four
hunters at once.    All the same, none of them tried to flee, but instead,
they attacked the bear with all their strength.  Even the youngest hunter
exerted himself well beyond his own capabilities.    The bear roared at the
assaults, but curiously did not fight back.  It continued running from the
hunters until its many injuries caused it to collapse.   The hunters seized
their advantage and killed the bear.     They then started the daunting
task of dismembering the creature.    "Here shall we have enough meat to
feed our people for many moons," the youngest hunter said  eagerly.
 After many exhausting hours, they finally collected vast mounds of bear
meat.

Even as they wondered how they would be able to deliver the meat back to
their village, the eldest hunter looked down and said, "We are now where we
think we are.  Behold!"    The hunters looked down and instead of ground
saw only stars.   The youngest hunter gasped, "We are in the sky!"    Even
more astonishing was that the bear and the hunters were all glowing
brightly.       The second youngest proclaimed, "The Bear used its magic to
lure us out of the village and into the night world.  We are now stars."
 Suddenly, Nyah-Gwaheh's flesh and bones fell together into a pile and from
it the bear arose, fully alive.   The astonished hunters watched it laugh
joyfully at them and then bound away.    They, too,  began to laugh and
resumed the chase which lasted all night.

[image: 8248c487e22af2751978373f6e2b1dc3.jpg]

Each night, we watch the hunters pursue the bear through the northern sky
  The four hunters are each stars within the pattern we call the Big
Dipper.  The bear, itself, is so large that it is formed by the four stars
within the dipper's bowl.        Though we often see only three stars in
the Big Dipper's handle, four are actually present.   One small star is
next to the handle's center star: this small star is the youngest hunter
who, being slower than the others, is farther away from us and so appears
tinier.

The hunters chase the bear in perpetuity.   It is said that every autumn
they capture and kill it. At this time, the blood rains down from heaven to
coat the trees in red.  In the winter, the famished hunters cook the bear
in its own boiled fat that gushes down onto the world and coats it in
white.   In the spring the bear is resurrected and with it the land,
itself, is rejuvenated.   During the summer, when the days are longest, the
hunters chase the bear all day and night, only to kill it again when autumn
arrives.

THE SOUTHWORTH PLANETARIUM
207-780-4249   www.usm.maine.edu/planet
<http://www.google.com/url?q=http%3A%2F%2Fwww.usm.maine.edu%2Fplanet&sa=D&sntz=1&usg=AFQjCNHulkHuLP13bOG2PkNrPazsGWFs2A>
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Altitude:  10 feet below sea level
Founded January 1970
Julian Date:  2459226.18
2020-2021:  LXX

THE DAILY ASTRONOMER
Tuesday, January 12, 2021
Exploratorium V:  Before and After Tycho  Part II


*Part II:   After*

*Time: *
        108 million years ago

*Location:*
         Earth   Mid-Cretaceous period


While we watch the blinding flash on the moon caused by the asteroid
impact, we should now explain how much we can know and what we can't know
as we embark on these imaginary excursions to remote space-time
destinations.     We are confident that 108 million years before our home
time period, an asteroid crashed onto the moon to create the structure we
now call "Crater Tycho."      We are also quite certain that Earth looks
quite different in the mid-Cretaceous than it does in modern day due to
tectonic shifting.

We don't know the correct lunar phase:  was the moon full or new or at
waning crescent or at some other phase?   I decided to make the moon full
for dramatic effect.    The actual phase is, like so much of the past,
unknowable.    We can go on these voyages because the scientific method
humans developed have given us powerful tools to determine much of what
transpired in the past and many events that will occur in the future.
    But, not everything.

As we jump through different time periods, we will begin to know much more
about Crater Tycho and why it is so named.     For now, we recline in the
miasmic mid-Cretaceous world and admire the incandescent flash of the
asteroid impact.      We don't know also if the dinosaurs and other
creatures are noticing the light.   It would be rather ironic if they did,
as a similar impact will end the Cretaceous period (and the era of the
non-avian dinosaurs) in about 43 million years from now.     Although we
can't see it, the plummeting asteroid vaporized on impact and left a crater
more than 80 miles wide and four miles deep.   Rays extending in all
directions attest to the impact's power as material will scatter along the
lunar terrain and even into outer space.     The moon's gravity is 1/6th as
powerful as Earth's so many fragments displaced by the impact will escape
the moon's gravity.    Some of these lunar meteorites will likely land on
Earth.


_______________________________________________

[image: Allan_Hills_81005,_lunar_meteorite.jpg]
*Allan Hills A81005*
The first lunar meteorite discovered on Earth was found by John Schutt and
Ian Whillans in 1982.  This specimen was named for the Allan Hills, which
are part of the Transantarctic Mountain range in Antarctica where many
meteorites are found.   Chemical analysis shows it to have been a lunar
fragment.  Since its discovery, more than 370 lunar meteorites have been
found on Earth.
______________________________________________

[image: download.jpg]

So, the questions remain:  why does it still remain on the lunar terrain
after all these years, why do we call it Crater Tycho (or Tycho Crater, if
you prefer),and how can we possibly know its age?

Well, the first question is rather simple. Remember when we stood on the
moon's surface and observed the crystalline sky?   The night sky was so
clear because the moon lacks an atmosphere.    It also lacks any flowing
water or weather systems of any kind.  There is no erosion on the moon as
one would find on Earth.  The craters remain for millions or billions of
years.

Now, as to the name....


*Time*
           1575 (AD/CE)

*Location*
           Island of Hveen

A small, beautiful Swedish island.    That incomplete structure one can
observe in the distance is the beginning of Uraniborg, an observatory run
by Danish astronomer Tycho Brahe.   He will be using that observatory to
make meticulous observations of Mars.   I decided to land here so as to not
encounter him or any one else.  From all accounts, he is rather an
eccentric fellow with many disagreeable traits : a person best admired from
a distance.  Eventually,his more congenial mathematical assistant Johannes
Kepler will analyze these records to devise his three famous planetary
laws.    We repeat them here:


   - Every planet's orbit is an ellipse with the Sun at one focus.
   - The closer the planet is to the Sun the faster it moves (Or, a radius
   vector connecting planets to the Sun sweep out equal areas in equal time
   intervals.
   - The square of a planet's period is proportional to the cube of its
   semi-major axis. (mean distance.)


Kepler would not have been able to discover these laws were it not for
Tycho's highly detailed observations.      For this reason, Tycho Brahe is
considered the grand patriarch of observational astronomy.   His
accomplishments are all the more impressive considering that he died almost
a decade before Hans Lippershey invented the telescope.


Next destination:

*Time*
     June 1598

*Location*
           Ferrara, a province in northern Italy.

Sigh.
Yes, we're looking down at a napping baby.   His name is Giovanni Battista
Riccioli. He is two months old and sleeping soundly despite our presence.
 Even if he awakens to see us, the ramifications to the time stream will
likely be minimal.       Though he will mature to become one of Italy's
foremost astronomers, Riccioli won't become nearly as famous as the revered
native son Galileo.    However, he will be quite noteworthy for his
published works, including the 1651  Almagestum Novum ("New Almagest") in
which he included lunar charts with named craters.  He started the practice
of assigning proper names to craters, including Tycho, who, in 1598, is
still alive and will soon begin work with Kepler.   Tycho died about half a
century before the New Almagest's publication.  By that time, of course, he
experienced something of an astronomical apotheosis: a person worthy of
being the namesake of the moon's most prominent crater.

And, finally...

*Time*
        December 7, 1792

*Location*
         Kennedy Space Center Launch Complex 39

Cover your ears!
A Saturn V rocket just issued that thunderous sound.   The skyscraper-tall
rocket has just left Earth's surface.   There it is: like a dart propelled
by contrails against the boundless blue sky.      Three astronauts,
Harrison "Jack" Schmidt, Eugene Cernan, and Ronald Evans, are aboard the
vessel en route to the moon.     Schmidt and Cernan will be the last two
Apollo astronauts to walk on the moon.  (Evans will remain in the
capsule.)    Although they will land well away from the Tycho Crater, the
Apollo 17 astronauts will collect material believed to have been expelled
by the impact that created it.     Through the process of radiometric
dating, geologists analyzed the rocks these astronauts collected to
ascertain an age of 108 million years.

Understanding radiometric dating requires a discussion about half life.
Every radioactive substance emits radiation and in the process becomes a
different element.     The amount of time required for one half of a given
radioactive sample to disintegrate into its daughter element is known as a
half life.     Let's say a given substance has a half life of 20 years,
just to make the math simple.     If one had 10 kilogram of that material
today, only 5 kilograms would remain after 20 years.  Only 2.5 kilograms
would remain after 40 years and 1.25 kilograms after 60 years.
 Fortunately, many elements are radioactive and have half lives measuring
in the thousands, millions or even billions of years.        Consequently,
the ages of extremely old objects such as Earth and Crater Tycho can be
ascertained by measuring the ratio of a parent radioactive product to a
daughter product.


Understanding the natural and cultural history of Crater Tycho required a
few leaps around the space-time continuum.   We know why it exists, how
long ago it was formed and why it is named Tycho.   We also knot that it
will likely last as long as the moon does.  The only erosive force on the
moon is through  micro-meteorite cratering.  Just think of little sand
particles that strike the ground every so often.   These micro meteorites
will need about half a million years to wick away the Apollo astronaut
footprints.    Not nearly enough time will elapse so as to erase a crater
the size of Tycho.

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