THE SOUTHWORTH PLANETARIUM
207-780-4249       www.usm.maine.edu/planet
70 Falmouth Street  Portland, Maine 04103
43.6667° N                   70.2667° W
Founded January 1970
           "Happiness: a freshly fallen shroud of snow, a brisk polar gale.
the scintillations of pristine ice crystallizing on a cooling lake, all the
majesty of winter...coming soon to the Southern Hemisphere. ha ha!"



*THE DAILY ASTRONOMER*

*Tuesday, June 14, 2016*
*Ricochet*


Hello!
I hope you don't mind, but I am too tired to write anything today, so I
wanted instead just to talk to you.  I assure you that I will not wax
philosophical, disclose any personal problems, or attempt to persuade you
to alter a political opinion.   Simply, this is a good day to put away the
computer and just speak.

Yesterday, we posted yet another Pandora article.   One subscriber recently
suggested that we rename this silly service the "Daily Pandora."  (Will
consider that idea.)  We've gone to Pandora's Jar so often because we have
been inundated with questions and are all the happier for the deluge.     I
have found that the answer to one question often elicits many other
questions, which, in turn, generate others, so that what began as a single
inquiry blossoms dendritically into a series of questions.       Every so
often, however, one question ruptures the levee and we are submerged in the
unabated outflow.

Case in point:   Yesterday's bullet question.  The question read:


*"Is it true that if you fire a bullet at the same moment that you drop a
bullet from the same height, they will hit the ground at the same time?" *
I hastily wrote the answer (or a cursory version of an answer) as I saw
that noon had already passed and so in a flurry completed and posted the
DA.  About half an hour later (after lunching with the ambassador) I opened
the e-mail account and noticed that the DA has generated fifteen
responses!     This is generally about fifteen more than usual.
My first reaction was abject horror and profound shame.    Remember those
moments as a child when, let's say, you were playing left field in a
baseball game and while you wondered if the dryads in the nearby forest
ever assumed their natural form without moonlight, the ball landed an inch
in front of you and as you stood oblivious to it, the opposing team drove
in three runs and won the game that you're team would have won had the ball
well, been moved from its landing site.    And, then, when the banshee
shouts of about three billions of Earth's inhabitants awakened you from
your reverie, you found yourself in the focal point of wrath powerful
enough to flip over Madagascar?

Well, I experienced a similar feeling yesterday as I assumed the fifteen
responses were reproaches for posting a bullet question so soon after that
despicable event in Orlando*  But, no.  Instead, some subscribers were
disputing the answer and offering their own.

The problem with the question pertains to something that was left out.
If a bullet is dropped from the same height as a bullet that is fired
HORIZONTALLY from a gun, they will land at the same time.    I neglected to
include that small, but immensely important, qualification.   If a bullet
is fired up an at angle, it will land after the dropped bullet.
Conversely, if a bullet is fired down at an angle, it will land before the
dropped bullet.

Also, someone told me that they would have answered the question
differently, because the question also assumes that the bullet is fired on
a flat Earth.  The times would not be equal on an planet where the
acceleration is radial.    This statement is quite true and insightful.

Someone else did remark that I did likely intend to say the gun was fired
horizontally, but added that holding anything horizontal is almost
impossible.   In this messy, non linear world, it would invariably be held
at a slight angle.

However, if we can pretend that we live in a physics text book where
everything can be situated for our convenience, a bullet fired horizontally
would strike the ground at the same time as a bullet dropped from the same
height at the same moment because the downward pull of gravity is acting
equally on both bullets.    The fired bullet would travel farther
horizontally, of course, but the two objects fall from the same height and
descend at the same rate.

I hope this talk has help clarify matters.  I apologize for my tendency to
omit important details.     And, I also apologize for not writing an
article today.  The weather is becoming increasingly more gorgeous and I
decided to be a lazy cad.  I promise to be more responsible tomorrow.



*If anybody was offended, I do apologize.    You see, I used to rely on the
late Shadow Professor to advise me whenever I would wonder if an article
should or shouldn't be posted.  Now that he has moved on, I am left to my
own devices, which are often faulty.

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FROM THE CATACOMBS OF INFINITE KNOWLEDGE
The north star, Polaris, is not exactly aligned with the north celestial
pole, nor will it ever be.    Precessional motion, the 'wobbling' that
causes Earth's poles to describe wide circles through space over a 26,000
year period, is currently moving the North Celestial Pole closer to
Polaris.  In 2102, Polaris will attain its minimum distance from the North
Celestial Pole of 27 arc-minutes.    Then, the North Celestial Pole will
slowly shift away from it.
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