[image: Waterhouse-sleep_and_his_half-brother_death-1874.jpg]
*Hypnos:*  *God of Sleep*
During the early ages, the mythological Universe was born out of chaos, an
indefinable nothing.     From this unbounded chasm arose all that was to
exist in the rarefied realm through which we daily travel.    Soon after
this inception event, the cosmos underwent a rapid differentiation:  light
separated from dark; Earth descended below sky; and the unattainable
heavens rose above the underworld realms that plummeted into unsounded
depths.  So, too, were the primordial deities born: the personifications of
every aspect of physical reality.    Among these were Aether ("Air"),
Hemera ("Day"), Nyx ("night") and Erebus ("darkness.").      Nyx wedded
Erebus and together they sired many children, including the Oneiroi, a
assembly of one thousand dream gods; the Keres, the thousand female
goddesses of violent and cruel deaths; the Moirai, or Fates -we met them
early in our voyages-, the three beautiful Hesperides, goddesses of sunset
and evening; and the twins Thanatos and Hypnos, the gods of death and
sleep, respectively.    Hypnos resided in a cave within the underworld, a
cave so remote that neither sunlight nor moonlight ever illuminated it.
Poppies and other soporific plants grew around this secret cave and the
river  Lethe (the waterway of forgetfulness) flowed through it.  Like his
twin brother, who presided over non-violent deaths, Hypnos was a calm god
who often sought to comfort instead of torment mortals.    Quite often
Hypnos would watch the shades of recently deceased people conveyed across
the River Styx and into the underworld.     At times Hypnos would assume
the form of a mortal who had died unexpectedly.  In this guise he visited
the dreams of the unfortunate person's relations, informed them of the
death and spoke lovingly to them before departing.  (Some writers claim
that his son, Morpheus, the god of dreams infiltrated the dreams,
instead.)   On only two occasions did Hypnos become involved in situations
he would have preferred to avoid.   Both involved Hera and Zeus, her all
powerful husband.     In the first instance, Hera was infuriated that
Heracles sacked Troy for reasons that we will discuss at a later date.
(Note:  Heracles sacked the city well before theTrojan War, which started
after his death.)      She so desperately wanted to punish Heracles for
this action that she summoned Hypnos from the underworld to help her.
Knowing that Heracles was under Zeus' constant protection, Hera persuaded
Hypnos to lull Zeus into a deep sleep. (Gods rarely, if ever, slept.)  As
soon as Zeus fell asleep, Hera then begged Poseidon to push Heracles' ship
with waves and powerful winds during his voyage away from Troy.    The
winds pushed Heracles off course so far he was adrift at sea for many
weeks.   When Zeus awakened and learned what had transpired during his
slumber, he realized that Hypnos must have coaxed him into a sleep while
Hera avenged Troy's destruction on Heracles.  Furious beyond measure, Zeus
searched frantically for Hypnos who wisely scampered down to the Underworld
and hid himself within the dark realm of his mother Nyx.    Years later,
Hera, who was then on the side of the Greeks during the Trojan War,
realized that the Greeks and Trojans were at an impasse.   She also knew
that Poseidon had wanted to help the Greeks and would have done so had Zeus
not prevented him from intervening.    Hera summoned Hypnos again to her
side and asked him once again to put Zeus into a deep sleep.  Hypnos was
understandably reluctant to accede to Hera's wishes a second time, for he
remembered -and would never forget- how he had incurred Zeus' murderous
rage the first time.      Even though Hera persisted, Hypnos remained firm
in his refusal.  She then offered to employ her influence as the goddess of
marriage to wed him to Pasithea, a beautiful young grace whom he had
coveted for a long time.    He then agreed to help Hera, but first made her
swear by the River Styx to fulfill her promise, which she promptly did.
  Hera told him to wait nearby.    She then adorned herself in her finest
clothing and with a charm given to her by Aphrodite, made herself more
alluring than she had ever been.     Hera then approached Zeus.   He was
astonished by her appearance and asked her to explain the reasons behind
it.  She told him that she was required to arbitrate a dispute between two
other gods, hence the need to drape herself in the finest regalia.   She
asked Zeus' permission to attend to the matter at once for he was the
ultimate authority in such matters.  Zeus granted the request at once.
Before she left, however, he was so enraptured by her beauty he embraced
her.   Hera then motioned for Hypnos to come forward and cast the sleep
spell on Zeus.    Zeus then dozed while Poseidon joined the Greek campaign,
which turned the tide of the war.   It was said that the Greeks had already
left the Trojan Horse on shore and departed to a nearby island.    That
night, after the Trojans drew the horse inside the gates, Poseidon cast off
the winds that hastened the Greek vessels back to Troy.   Thus all the
Greeks were present when the soldiers within the horse withdrew from it and
opened the gates.  They then destroyed Troy, thereby ending the war.
That time when Zeus awoke he did not realize he had fallen asleep under an
enchantment for Hypnos had anointed his eyes with droplets from Lethe and
so forgot all that had occurred just before he lapsed into an enchanted
sleep again.       After this exploit, Hypnos confined himself to the dark
realm of mortal sleep, a far safer place, indeed, than Olympus.


THE SOUTHWORTH PLANETARIUM
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2019-2020:  CLXXXIII


THE DAILY ASTRONOMER
Thursday, July 23, 2020
Remote Planetarium 70:  Exo-Planets Q/A

Today we conclude our series about exo-planets with a brief Q/A.   If you
have any questions not addressed in this article, please send them to me!

*Where is the nearest exo-planet?*
The nearest exo-planet is as close as the closest star, Proxima Centauri.
 Astronomers have found two planets in orbit around Proxima, the red dwarf
star that is part of the Alpha Centauri system.    Proxima Centauri is 4.2
light years away from Earth.      These planets are known as Proxima
Centauri b and Proxima Centauri c.   The second of these planets is seven
times more massive than Earth and revolves well outside the habitable
zone.  The first planet's mass is only slightly greater than that of our
home planet and is well within that zone.   Because Proxima Centauri is a
red dwarf star, its habitable zone is very close to it.  Proxima Centauri
b's mean distance from its parent star is only 3.7 million miles and it
completes one orbit every 11.2 days.     While this planet could harbor
life as it is both terrestrial and within the habitable zone, it is also
subjected to strong stellar winds: 2000 times more powerful than the solar
winds we experience on Earth.     Such a high bombardment of radiation
might preclude life's development on Proxima Centauri b.

*Is it true that astronomers have found an exo-planet in the Andromeda
Galaxy?*
Possibly.   PA-99-N2 is a microlensing event observed in the Andromeda
Galaxy, 2.2 million light years from the Milky Way.   It is possible that a
star within the galaxy micro lensed either a smaller star or a planet.
Micro lensing occurs when a massive body in front of a luminous one causes
the light to bend gravitationally around it, by which it produces two
images.  The identity of the microlensing body remains a matter of
contention.  If confirmed, that object would be the most distant exo-planet
yet discovered.

*Have any exoplanets  been directly imaged?*
Yes, quite a few of them, actually.   If the planet revolves at a
sufficient distance away from its parent star, it can be resolved, provided
that the star is also relatively close to us.    As of now, about two dozen
exo-planets have been discovered through direct imaging.*  With one
exception (CVSO 30 c), these directly imaged exo planets are located less
than 1000 light years from Earth.

[image:
lossy-page1-1280px-Stunning_Exoplanet_Time-lapse_Beta_Pictoris_b.tif.jpg]
*Time lapse images of Beta Pictoris b, a planet around Beta Pictoris.*

*Are there many planets around double, triple and even quadruple star
systems? *
So many people want a Tatooine sky:  two or more suns in view!
Fortunately, there might be quite a few.   According to a 2019 survey,
within 1600 light years of the Sun there could be 176 binary stars, 27
triples and at least one quadruple star that contains planets.       The
types of orbits will vary however.   For instance, astronomers recognize "P
type," "S type" and "T type" orbits within a binary system.     A planet
moving along a S-type orbit revolves around only one star within the
system.  A planet in a P-type orbit revolves around both.
In a T-type orbit, the planet would be around one of the two main L points
along the secondary star's orbit.      Any system consisting of two
gravitationally bound bodies will also contain five L points (Lagrangian
equilibrium stability points.)  Three of these points are located along a
straight line connecting the bodies.   Two others are along the secondary
body's orbit, one sixty degrees ahead, the other sixty degrees behind.
 These are the two most stable L points and one could find planets within
their vicinity.    See graphic below.


[image: exoplanetorbits.png]


*Some of these directly imaged planets might instead be brown dwarfs,
gaseous bodies that never became massive enough to ignite the core
thermonuclear fusion reactions that power stars.


______________________________________
SKYWATCHING TIP OF THE DAY:   Mercury in the morning
Mercury reached greatest elongation on July 22nd. At that time, the first
world appeared 20 degrees from the Sun in the pre-dawn eastern sky.    Try
to find Mercury throughout the remainder of this week.   Venture out around
4:30 a.m. and find an unobstructed eastern horizon.
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