Ticker for July 20, 2005

                
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A Ticker Homework Assignment

Tonight, on the 36th anniversary of our first lunar visit, we'll
see a full moon. But we may not see it truthfully. In fact, the
full moon may mess with our minds tonight.

Throughout the course of humanity, we have pinned many natural and
supernatural events on the moon. It circles the earth unassumedly,
yet assuming an enigmatic spectrum of human roles. The moon is so
precisely reliable that it underpins many cultures' calendars, yet
so mysterious that we connect it to werewolves and vampires lurking
in our collective psyche.

We just aren't quite able to exactly define our celestial attendant.

Its existence is tangible enough to tug at oceans, so we've blamed it
for pulling the tides of our minds (we didn't invent the word "lunatic"
by coincidence). The orb has inspired poems, prose and prayer from a
race wondering why in the heck it exists. Naturally, it is the first
otherworld we troubled to visit, using our very best mathematics and
engineering ... yet we retained enough of our natural lunar intrigue
to quarantine the returning astronauts for possible "moon germs".

The moon is one of humanity's ongoing mysteries. How can something
so predictiable be so perplexing? How can the moon seem so serene,
despite its violently battered surface? How can a silent rock,
throughout the history of mankind, rise to rhymes and rites, then
set to songs and sermons?

Here's another enigma. Have you ever noticed that the moon looks so
much bigger on the horizon than it does in the sky? How many times
have you said to yourself "Wow! What a big moon!" as it inches
above the trees?

Well, even that phenomenon is mysterious.  Most of us (Ticker Staff
included) just assume this is some artifact of optics, a distortion
by the atmosphere that magnifies its image. But it is no such thing:
in fact, the moon near the horizon is the same angular size (it takes
up the same amount of sky) as when it rides high!

You can see this for yourself tonight.  Shortly before sunset, the
full moon will appear on the horizon of the eastern sky.  Hold your
thumb at arm's length toward the rising moon. Notice how big the
moon is compared to your thumb. Then try it again several hours
later. The moon will be the same size relative to your thumb! But
most of us, when not using our thumb, will "see" the moon as much
larger upon moonrise.

It's uncanny!  And we can't repoduce the effect with cameras, video,
artwork, print, other media. Our brains aren't fooled by these
devices. The illusion happens hen we are standing on the earth
looking at the moon.

Why is this? Well, as one would expect with the moon, the answer:

1. isn't completely understood.
2. involves psychology.

There are several competing theories, but the illusion is certainly
produced somewhere in our minds. It may have something to do with
the way our brains assign distance to an object, or it may have
something to do with how our minds are overwhelmed by the moon's
largeness.

But this much is clear: the moon still enjoys its special and
mysterious relationship with our psyche. It still perplexes today's
psychologists, puzzling the minds that solve the mind's puzzles.

So, as you complete your Ticker homework assignment tonight, keep
in mind you're the latest of a cast of billions. Regardless of the
topic at hand - tides, ails, ills, luck, or optical trickery -
billions before you who have looked skyward and wondered "Moon, how
did you do that?".